Patent Publication Number: US-2022212602-A1

Title: Harvester, System, Program, Recording Medium, and Method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the United States national phase of International Application No. PCT/JP2020/024937 filed Jun. 25, 2020, and claims priority to Japanese Patent Application Nos. 2019-121783 filed Jun. 28, 2019, 2019-121784 filed Jun. 28, 2019, 2019-121785 filed Jun. 28, 2019, and 2019-121786 filed Jun. 28, 2019, the disclosures of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a harvester, a system, a program, a recording medium, and a method. 
     Description of Related Art 
     Conventionally, a technique of displaying an overhead image in a display device is used to make a driver aware of a vehicle&#39;s surroundings. A vehicle driving assistance device described in JP 2007-183877A (Patent Document 1) uses four on-board cameras to shoot images of regions to the front, the rear, and the left and right sides of a vehicle, respectively, stitches the shot images together and converts the images into an image looking down on the host vehicle from a virtual viewpoint thereabove, and superimposes the stitched image over a virtual image of the host vehicle to display a single overhead image that makes the driver aware of the host vehicle&#39;s surroundings. 
     As indicated in the drawings, the vehicle driving assistance device described in Patent Document 1 is for passenger vehicles, and is intended to assist in parking. The four on-board cameras are installed on a front bumper, a rear bumper, and left and right side mirrors. 
     JP 2019-4868A (Patent Document 2) describes a display device provided in a combine. A screen unit of this display device is divided into a camera image region capable of displaying a shot image shot by a camera provided in a vehicle body, and two specific state information regions arranged on the left and right sides of the camera image region. The specific state information regions display information about the vehicle body, such as the rotation speed of the power source, a level of raw rice in the vehicle body, and the like. 
     Patent Document 1: JP 2007-183877A 
     Patent Document 2: JP 2019-4868A 
     SUMMARY OF THE INVENTION 
     Patent Document 1 only discloses a technique for displaying an overhead image in a passenger vehicle, and neither discloses nor suggests displaying images for recognizing the surroundings of a harvester such as a combine, locations of on-board cameras suited to harvesters, or the like. 
     An object of the present invention is to provide a means for making it easier to understand a work environment around a harvester. 
     Patent Document 1 only discloses a technique for displaying an overhead image in a passenger vehicle, and neither discloses nor suggests displaying images for recognizing the surroundings of a harvester such as a combine, locations of on-board cameras suited to harvesters, or the like. 
     An object of the present invention is to provide a means for making it easier to understand a work environment around a harvester, a state of the harvester, and the like. 
     Patent Document 1 only discloses a technique for displaying an overhead image in a passenger vehicle. Patent Document 1 neither discloses nor suggests displaying images for recognizing a vehicle body, the surroundings, and so on of a harvester such as a combine, selecting a shooting range suited to a harvester, or the like. 
     An object of the present invention is to provide a means for making it easier to understand a work environment around a harvester, a state of the harvester, and the like. 
     With the display device described in Patent Document 2, a region where a shot image shot by a camera and a region where information about the vehicle body is displayed are separated. Accordingly, it may be difficult to grasp, at a glance, what the information displayed is about, what part of the vehicle body the information is about, and so on. 
     An object of the present invention is to provide a means for displaying information related to harvesting operations in an easy-to-understand manner. 
     As a means to solve the above-described first problem, a harvester according to the present invention includes: a vehicle body; a front camera, a rear camera, a first side camera, and a second side camera that shoot a vicinity of the vehicle body and generate shot images; a storage unit for storing vehicle body data indicating an external shape of the vehicle body; an image compositing unit that generates a composite image showing the vehicle body and the vicinity of the vehicle body based on (i) the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and (ii) the vehicle body data stored in the storage unit; and a display unit that displays the composite image generated by the image compositing unit. The vehicle body includes a harvesting unit that harvests a crop in a field, a driving section provided behind the harvesting unit, a transport unit that is provided laterally to the driving section and that transports a harvested crop harvested by the harvesting unit, a threshing device that is provided behind the transport unit and that threshes the harvested crop transported by the transport unit, a grain tank that is provided behind the driving section and laterally to the threshing device and that stores grain obtained by the threshing device, a discharge device that is provided behind the grain tank and that discharges the grain stored in the grain tank to outside, and a rear cover part that covers the discharge device or the threshing device from behind. The front camera is provided on a front part of the driving section, the rear camera is provided on the rear cover part, the first side camera is provided on (i) a side part of the driving section on an outer side in a left-right direction of the vehicle body or (ii) a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided on a side part of the threshing device on an outer side in the left-right direction of the vehicle body. 
     According to this feature, a composite image based on the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and the vehicle body data is displayed in the display unit, and the vehicle body and the vicinity thereof are shown. In other words, the state in the vicinity of the harvester is displayed in the display unit, which makes it easy to grasp the work environment. Additionally, the front camera is provided on a front part of the driving section, the rear camera is provided on the rear cover part, the first side camera is provided on a side part of the driving section on an outer side in a left-right direction of the vehicle body or a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided on a side part of the threshing device on an outer side in the left-right direction of the vehicle body, and thus a wide range in four directions around the vehicle body can be shot in a harvester in which the harvesting unit, the driving section, the threshing device, the grain tank, and the rear cover part are arranged as described above. Accordingly, a wide range around the vehicle body can be shown in the composite image, which makes it easier to grasp the work environment in the vicinity of the harvester. 
     As a means to solve the above-described first problem, a harvester according to the present invention includes: a vehicle body; a front camera, a rear camera, a first side camera, and a second side camera that shoot a vicinity of the vehicle body and generate shot images; a storage unit for storing vehicle body data indicating an external shape of the vehicle body; an image compositing unit that generates a composite image showing the vehicle body and the vicinity of the vehicle body based on (i) the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and (ii) the vehicle body data stored in the storage unit; and a display unit that displays the composite image generated by the image compositing unit. The vehicle body includes a harvesting unit that harvests a crop in a field, a driving section provided behind the harvesting unit, a transport unit that is provided laterally to the driving section and that transports a harvested crop harvested by the harvesting unit, a threshing device that is provided behind the transport unit and that threshes the harvested crop transported by the transport unit, and a grain tank that is provided behind the driving section and laterally to the threshing device and that stores grain obtained by the threshing device. The front camera is provided on a front part of the driving section, the rear camera is provided on a rear part of the threshing device or the grain tank, the first side camera is provided on (i) a side part of the driving section on an outer side in a left-right direction of the vehicle body or (ii) a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided on a side part of the threshing device on an outer side in the left-right direction of the vehicle body. 
     According to this feature, a composite image based on the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and the vehicle body data is displayed in the display unit, and the vehicle body and the vicinity thereof are shown. In other words, the state in the vicinity of the harvester is displayed in the display unit, which makes it easy to grasp the work environment. Additionally, the front camera is provided on a front part of the driving section, the rear camera is provided on a rear part of the threshing device or the grain tank, the first side camera is provided on a side part of the driving section on an outer side in a left-right direction of the vehicle body or a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided on a side part of the threshing device on an outer side in the left-right direction of the vehicle body, and thus a wide range in four directions around the vehicle body can be shot in a harvester in which the harvesting unit, the driving section, the threshing device, and the grain tank are arranged as described above. Accordingly, a wide range around the vehicle body can be shown in the composite image, which makes it easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the front camera and the rear camera are located in a central part in the left-right direction of the vehicle body. 
     According to this feature, the front camera and the rear camera are located in a central part of the vehicle body in the left-right direction, and thus a wide range to the front and the rear of the vehicle body can be shot. Accordingly, a wide range to the front and the rear of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the front camera is provided on the front part of the driving section, and is adjacent to the transport unit. 
     According to this feature, the front camera is provided on the front part of the driving section, and is adjacent to the transport unit, and thus the front camera is located toward the center of the vehicle body in the left-right direction. Accordingly, a wide range to the front of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the first side camera is provided on a rear part of the driving section, and is adjacent on an outer side in the left-right direction of the vehicle body. 
     According to this feature, the first side camera is provided on a rear part of the driving section, and is adjacent on an outer side in the left-right direction of the vehicle body, and thus the first side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the first side camera is provided behind a driver&#39;s seat included in the driving section. 
     According to this feature, the first side camera is provided behind a driver&#39;s seat included in the driving section, and thus the first side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the harvester further includes an engine provided below the driver&#39;s seat, a radiator provided on an opposite side of the transport unit to the engine, and a dust-resistant unit that is provided on an opposite side of the transport unit to the radiator and that removes dust from outside air supplied to the radiator, and the first side camera is provided above the dust-resistant unit. 
     According to this feature, the first side camera is provided above the dust-resistant unit, and thus the first side camera is located toward the top and the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, a roof part included in the driving section includes a projecting part that projects farther outward in the left-right direction of the vehicle body than a side glass, and the first side camera is provided directly below the projecting part. 
     According to this feature, because the first side camera is provided directly below the projecting part, the projecting part suppresses direct sunlight from entering the first side camera, which makes it possible to improve the quality of the shot image generated by the first side camera. This makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the first side camera is provided on a front part of the grain tank, adjacent on an outer side in the left-right direction of the vehicle body. 
     According to this feature, the first side camera is provided on a front part of the grain tank, adjacent on an outer side in the left-right direction of the vehicle body, and thus the first side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the second side camera is provided on a front part of the threshing device, adjacent on an outer side in the left-right direction of the vehicle body. 
     According to this feature, the second side camera is provided on a front part of the threshing device, adjacent on an outer side in the left-right direction of the vehicle body, and thus the second side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the threshing device includes a main body part and a top panel that opens and closes an opening provided in an upper surface of the main body part, and the second side camera is provided on the front part of the threshing device, and on a part of the upper surface of the main body part located farther outward than the top panel. 
     According to this feature, second side camera is provided on the front part of the threshing device, and on a part of the upper surface of the main body part located farther outward than the top panel, and thus the second side camera is located toward the top and the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     As a means to solve the above-described second problem, a harvester according to the present invention includes: a vehicle body; a front camera, a rear camera, a first side camera, and a second side camera that shoot a vicinity of the vehicle body and generate shot images; a storage unit for storing vehicle body data indicating an external shape of the vehicle body; an image compositing unit that generates a composite image showing the vehicle body and the vicinity of the vehicle body based on (i) the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and (ii) the vehicle body data stored in the storage unit; and a display unit that displays the composite image generated by the image compositing unit. The vehicle body includes a harvesting unit that harvests a crop in a field, a driving section provided behind the harvesting unit, a transport unit that is provided laterally to the driving section and that transports a harvested crop harvested by the harvesting unit, a feed chain that transports the harvested crop transported by the transport unit toward a rear, a threshing device that is provided behind the transport unit and that threshes the harvested crop transported by the feed chain, and a grain tank that is provided behind the driving section and laterally to the threshing device and that stores grain obtained by the threshing device. The front camera is provided on a front part of the driving section, the rear camera is provided on a rear part of the threshing device or the grain tank, the first side camera is provided on (i) a side part of the driving section on an outer side in a left-right direction of the vehicle body or (ii) a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided above a receiving part where the harvested crop is received by the feed chain from the transport unit. 
     According to this feature, a composite image based on the shot images generated by the front camera, the rear camera, the first side camera, and the second side camera and the vehicle body data is displayed in the display unit, and the vehicle body and the vicinity thereof are shown. In other words, the state in the vicinity of the harvester is displayed in the display unit, which makes it easy to grasp the work environment. Additionally, the front camera is provided on a front part of the driving section, the rear camera is provided on a rear part of the threshing device or the grain tank, the first side camera is provided on a side part of the driving section on an outer side in a left-right direction of the vehicle body or a side part of the grain tank on an outer side in the left-right direction of the vehicle body, and the second side camera is provided above a receiving part where the harvested crop is received by the feed chain from the transport unit, and thus a wide range in four directions around the vehicle body can be shot in a harvester in which the harvesting unit, the driving section, the threshing device, and the grain tank are arranged as described above. Accordingly, a wide range around the vehicle body can be shown in the composite image, which makes it easier to grasp the work environment in the vicinity of the harvester. 
     Additionally, because the second side camera is provided above the receiving part where the harvested crop is received by the feed chain from the transport unit, the receiving part can be shown in the composite image, which makes it easier to grasp the state of receiving of the harvested crop. 
     In the present invention, preferably, the second side camera is provided so as to be capable of shooting the receiving part. 
     According to this feature, the second side camera is provided so as to be capable of shooting the receiving part. As such, when the second side camera shoots the receiving part, the receiving part can be shown in the composite image, which makes it easier to grasp the state of receiving of the harvested crop. 
     In the present invention, preferably, a rail stand located vertically opposite to the feed chain such that the rail stand and the feed chain sandwich the harvested crop, and the second side camera is provided farther forward than the rail stand. 
     According to this feature, the second side camera is provided farther forward than the rail stand, which makes it easy to show the state of the harvesting unit progressing between the rail stand and the feed chain in the composite image, and makes it easier to grasp the state of receiving of the harvested crop. 
     In the present invention, preferably, the second side camera is provided forward of an outer part of a front wall included in the threshing device. 
     According to this feature, the second side camera is provided foward of an outer part of a front wall included in the threshing device. As such, the second side camera is supported by the sturdy front wall, and the state of receiving of the harvested crop can be shot reliably. 
     In the present invention, preferably, the first side camera is provided farther forward than the grain tank. 
     According to this feature, the first side camera is provided farther forward than the grain tank, and thus the first side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the first side camera is provided behind a driver&#39;s seat included in the driving section. 
     According to this feature, the first side camera is provided behind a driver&#39;s seat included in the driving section, and thus the first side camera is located toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the harvester further includes an engine provided below the driver&#39;s seat, a radiator provided on an opposite side of the transport unit to the engine, and a dust-resistant unit that is provided on an opposite side of the transport unit to the radiator and that removes dust from outside air supplied to the radiator, and the first side camera is provided above the dust-resistant unit. 
     According to this feature, the first side camera is provided above the dust-resistant unit, and thus the first side camera is located toward the top and the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, the first side camera is provided at a position higher than the grain tank. 
     According to this feature, the first side camera is provided at a position higher than the grain tank, and thus the first side camera is located toward the top and toward the center of the vehicle body in the front-back direction. Accordingly, a wide range to the side of the vehicle body can be shown in the composite image, which makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, a roof part included in the driving section includes a projecting part that projects farther outward in the left-right direction of the vehicle body than a side glass, and the first side camera is provided directly below the projecting part. 
     According to this feature, because the first side camera is provided directly below the projecting part, the projecting part suppresses direct sunlight from entering the first side camera, which makes it possible to improve the quality of the shot image generated by the first side camera. This makes it even easier to grasp the work environment in the vicinity of the harvester. 
     In the present invention, preferably, a satellite positioning module that detects a self vehicle position is provided, and the front camera, the rear camera, the first side camera, and the second side camera are provided at a position lower than the satellite positioning module. 
     According to this feature, all of the four cameras are provided at a position lower than the satellite positioning module, and thus the occurrence of adverse effects on the detection of the self vehicle position by the satellite positioning module due to the presence of the cameras can be suppressed. 
     As a means that solves the above-described third problem, a harvester according to the present invention includes: a vehicle body; a plurality of cameras that generate shot images; an image compositing unit that generates a composite image by compositing the shot images generated by the plurality of cameras into an image from a single viewpoint; and a display unit that displays the composite image generated by the image compositing unit. A harvesting unit and a front camera serving as one of the cameras are provided on a front part of the vehicle body, the front camera is provided such that part or all of the harvesting unit is included in a shooting range, and the part or all of the harvesting unit shot by the front camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, shot images from a plurality of cameras including the front camera are composited and displayed in the display unit. As such, the field, the state of the vehicle body, and the like over a relatively wide range can be grasped at a glance, which makes it easy to grasp the work environment in the vicinity of the harvester, the state of the harvester, and the like. Additionally, the front camera is provided such that part or all of the harvesting unit is included in the shooting range and the shot harvesting unit is shown in the composite image, and thus the state of the harvesting unit and the crop processed by the harvesting unit can therefore be grasped easily. 
     In the present invention, preferably, the harvesting unit includes a frame and an auger, the front camera is provided such that part or all of the frame and part or all of the auger are included in the shooting range, and the part or all of the frame and the part or all of the auger shot by the front camera are shown in the composite image generated by the image compositing unit. 
     According to this feature, the front camera includes the frame and the auger in the shooting range, and the shot frame and auger are shown in the composite image. As such, the state of the frame and the auger of the harvesting unit, and the state of the crop processed by the auger, can be grasped easily. 
     In the present invention, preferably, the front camera is provided such that a rear part of the frame and a region farther rearward than the frame are included in the shooting range, and the rear part of the frame and the region farther rearward than the frame, shot by the front camera, are shown in the composite image generated by the image compositing unit. 
     According to this feature, the front camera includes the rear part of the frame and a region farther rearward than the frame in the shooting range, and the rear part of the frame and the region farther rearward than the frame, which have been shot, are shown in the composite image. As such, the state of the rear part of the frame of the harvesting unit, and the state of the mowed area rearward from the frame, can be grasped easily. 
     In the present invention, preferably, the harvesting unit includes a lifting device that lifts a crop in a field, the front camera is provided such that part or all of the lifting device is included in the shooting range, and the part or all of the lifting device shot by the front camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the front camera includes the lifting device in the shooting range, and the lifting device which has been shot is shown in the composite image. As such, the state of the lifting device and the state of the crop lifted by the lifting device can be grasped easily. 
     In the present invention, preferably, the front camera is provided such that a region farther rearward than the lifting device is included in the shooting range, and the region farther rearward than the lifting device shot by the front camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the front camera includes the region farther rearward than the lifting device in the shooting range, and the region farther rearward from the lifting device which has been shot is shown in the composite image. As such, the state of the crop sent rearward from the lifting device can be grasped easily. 
     In the present invention, preferably, the harvesting unit includes a left divider and a right divider, the front camera is provided such that part or all of at least the left divider is included in the shooting range, and the part or all of the left divider shot by the front camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the front camera includes the left divider in the shooting range, and the left divider which has been shot is shown in the composite image. As such, the state of division of the crop in the field by the dividers can be grasped easily. 
     In the present invention, preferably, a waste straw processing device and a rear camera serving as one of the cameras are provided on a rear part of the vehicle body, the rear camera is provided such that part or all of the waste straw processing device is included in the shooting range, and the part or all of the waste straw processing device shot by the rear camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the rear camera includes the waste straw processing device in the shooting range, and the waste straw processing device which has been shot is shown in the composite image. As such, the state of processing of waste straw can be grasped easily. 
     In the present invention, preferably, the rear camera is provided such that a region farther rearward than the waste straw processing device is included in the shooting range, and the region farther rearward than the waste straw processing device shot by the rear camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the rear camera includes the region farther rearward than the waste straw processing device in the shooting range, and the region which has been shot is shown in the composite image. As such, the state of waste straw discharged from the waste straw processing device can be grasped easily. 
     In the present invention, preferably, a lower camera serving as one of the cameras at a position of the vehicle body below the front camera, the lower camera is provided such that a lower part of the vehicle body is included in a shooting range, and the lower part of the vehicle body shot by the lower camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the lower camera includes the lower part of the vehicle body in the shooting range, and the lower part of the vehicle body which has been shot is shown in the composite image. As such, the state of the lower part of the vehicle body can be grasped easily. 
     In the present invention, preferably, a traveling device in a lower part of the vehicle body, the lower camera is provided such that a front part of the traveling device is included in the shooting range, and the front part of the traveling device shot by the lower camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the lower camera includes the front part of the traveling device in the shooting range, and the front part of the traveling device which has been shot is shown in the composite image. As such, the state of the front part of the traveling device can be grasped easily. 
     In the present invention, preferably, a waste straw processing device is provided in a rear part of the vehicle body, the lower camera is provided such that a region below the waste straw processing device is included in the shooting range, and the region below the waste straw processing device shot by the lower camera is shown in the composite image generated by the image compositing unit. 
     According to this feature, the lower camera includes the region below the waste straw processing device in the shooting range, and the region below which has been shot is shown in the composite image. As such, the state of the region below the waste straw processing device (e.g., the mowed area, the state of the waste straw, and the like) can be grasped easily. 
     In the present invention, preferably, a feed chain that grips and transports the crop harvested by the harvesting unit and causes the threshing device to thresh the crop is provided, the lower camera is provided at a position lower than the feed chain and is provided such that a region below the feed chain is included in the shooting range, and the region below the feed chain shot by the lower camera is shown in the composite image generated by the image compositing unit. 
     When a camera is provided at a position higher than the feed chain, it is difficult to shoot a region below the feed chain (the field and the like) due to the presence of crops transported by the feed chain. According to this feature, the lower camera is provided at a position lower than the feed chain, the lower camera includes the region below the feed chain in the shooting range, and the region below which is shot is shown in the composite image. As such, the state of the region below the feed chain can be grasped easily. 
     As a means to solve the above-described fourth problem, a harvester according to the present invention includes: a vehicle body that performs harvesting operations for a crop while traveling in a field; a camera that generates a shot image; a display unit that displays an image; a storage unit for storing vehicle body data indicating an external shape of the vehicle body; a first compositing unit that generates a first composite image based on the shot image generated by the camera and the vehicle body data stored in the storage unit, the first composite image being an image showing the vehicle body and the field around the vehicle body; a second compositing unit that generates a second composite image by compositing an information presentation image indicating information related to the harvesting operations with the first composite image generated by the first compositing unit at a related position, the related position being a position in the first composite image which position is related to the information presentation image; and a display control unit that causes the second composite image generated by the second compositing unit to be displayed in the display unit. 
     According to this feature, an image indicating information related to the harvesting operations is composited with an image showing the vehicle body and the field in the vicinity of the vehicle body at a position related to that information, and is displayed in the display unit. As such, it is easy to understand to which part or position of the vehicle body, the field, or the like the information related to the harvesting operations is related. This makes it possible to improve the efficiency, safety, and the like of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image for an alert of an obstruction being present in the field, and the related position is a position in the first composite image which position corresponds to a position of the obstruction or a position in a vicinity of the obstruction. 
     According to this feature, an image for an alert of an obstruction being present in the field is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position of the obstruction or a position in the vicinity thereof, and is displayed in the display unit. As such, the presence of the obstruction can be understood easily. This makes the driver aware of the obstruction, and makes it possible to improve the safety of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image making an alert regarding a state of the vehicle body, and the related position is a position in the first composite image which position corresponds to a position of the vehicle body or a position in a vicinity of the vehicle body. 
     According to this feature, an image making an alert regarding the state of the vehicle body is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position of the vehicle body or a position in the vicinity thereof, and is displayed in the display unit. As such, the state of the vehicle body can be understood easily. This makes the driver aware of the state of the vehicle body, e.g., the speed of the vehicle body, the presence or absence of malfunctions, the capacity of the grain tank, and the like, which makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image indicating a state of the harvested crop, and the related position is a position in the first composite image which position corresponds to a position where the crop is harvested or a position in a vicinity of the position where the crop is harvested. 
     According to this feature, an image making an alert regarding the state of the harvested crop is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position where the harvested crop was harvested or a position in the vicinity thereof, and is displayed in the display unit. As such, the state of the harvested crop can be understood easily. This makes the driver aware of the state of the harvested crop, e.g., the quality, yield, and the like of the harvested crop, which makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image showing a state of a subregion that is a partial region of the field, and the related position is a position in the first composite image which position corresponds to a position of the subregion or a position in a vicinity of the subregion. 
     According to this feature, an image making an alert regarding the state of the subregion is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position of the subregion or a position in the vicinity thereof, and is displayed in the display unit. As such, the state of the subregion can be understood easily. This makes the driver aware of the state of the subregion in the field, e.g., a distinction between already-mowed/unmowed areas, whether crops are fallen, the growth state, and the like, which makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image showing a state of an unharvested crop in the subregion. 
     According to this feature, an image making an alert regarding the state of the crop in the subregion is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position of the subregion or a position in the vicinity thereof, and is displayed in the display unit. As such, the state of the unharvested crop in the subregion. This makes the driver aware of the state of the crop in the subregion in the field, e.g., whether crops are fallen, the growth state, and the like, which makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image showing a target path of the vehicle body, and the related position is a position of the first composite image forward on the target path. 
     According to this feature, an image showing the target path is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at a position forward on the target path, and displayed in the display unit. As such, the target path can be shown in an easy-to-understand manner. This makes the driver aware of the target path, and makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the information presentation image is an image showing that an event has occurred during harvesting operations, and the related position is a position in the first composite image which position corresponds to a position where the event occurred or a position in a vicinity of the position where the event occurred. 
     According to this feature, an image indicating that an event has occurred is composited with the image showing the vehicle body and the field in the vicinity of the vehicle body at the position where the event occurred or a position in the vicinity thereof, and displayed in the display unit. As such, the occurrence of an event can be shown in an easy-to-understand manner. This makes the driver aware of an event, e.g., that the grain tank has become full, a malfunction has occurred in the vehicle body, or the like, which makes it possible to improve the efficiency of the harvesting operations. 
     In the present invention, preferably, the harvester further includes a third compositing unit that generates a third composite image by compositing a map image with the second composite image generated by the second compositing unit, the map image being an image expressing a map indicating a point in the field corresponding to the related position, and the display control unit causes the third composite image generated by the third compositing unit to be displayed in the display unit. 
     According to this feature, a map indicating a point where an event has occurred is composited with an image showing the vehicle body and the field in the vicinity of the vehicle body, and displayed in the display unit. As such, the point where the event occurred can be shown to the driver in an easy-to-understand manner. This makes it possible for the driver to grasp, for example, at what point in the field the grain tank has become full. In other words, according to this feature, the driver is made aware of the point in the field where an event has occurred, as well as the state of the harvesting operations, which makes it possible to improve the efficiency of the harvesting operations. 
     As a means to solve the above-described fourth problem, a system according to the present invention includes: a harvester including a vehicle body that performs harvesting operations of a crop while traveling in a field and a camera that generates a shot image; a display unit that displays an image; a storage unit for storing vehicle body data indicating an external shape of the vehicle body; a first compositing unit that generates a first composite image based on the shot image generated by the camera and the vehicle body data stored in the storage unit, the first composite image being an image showing the vehicle body and the field around the vehicle body; a second compositing unit that generates a second composite image by compositing an information presentation image indicating information related to the harvesting operations with the first composite image generated by the first compositing unit at a related position, the related position being a position in the first composite image which position is related to the information presentation image; and a display control unit that causes the second composite image generated by the second compositing unit to be displayed in the display unit. 
     As a means to solve the above-described fourth problem, a program according to the present invention is a program for a harvester. The harvester includes a vehicle body that performs harvesting operations for a crop while traveling in a field, a camera that generates a shot image, a display unit that displays an image, and a storage unit for storing vehicle body data indicating an external shape of the vehicle body. The program causing a computer to implement: a first compositing function of generating a first composite image based on the shot image generated by the camera and the vehicle body data stored in the storage unit, the first composite image being an image showing the vehicle body and the field around the vehicle body; a second compositing function of generating a second composite image by compositing an information presentation image indicating information related to the harvesting operations with the first composite image generated by the first compositing unit at a related position, the related position being a position in the first composite image which position is related to the information presentation image; and a display control function that causes the second composite image generated by the second compositing function to be displayed in the display unit. 
     As a means to solve the above-described fourth problem, a recording medium according to the present invention is a recording medium in which is recorded a program for a harvester. The harvester includes a vehicle body that performs harvesting operations for a crop while traveling in a field, a camera that generates a shot image, a display unit that displays an image, and a storage unit for storing vehicle body data indicating an external shape of the vehicle body. The program causes a computer to implement: a first compositing function of generating a first composite image based on the shot image generated by the camera and the vehicle body data stored in the storage unit, the first composite image being an image showing the vehicle body and the field around the vehicle body; a second compositing function of generating a second composite image by compositing an information presentation image indicating information related to the harvesting operations with the first composite image generated by the first compositing unit at a related position, the related position being a position in the first composite image which position is related to the information presentation image; and a display control function that causes the second composite image generated by the second compositing function to be displayed in the display unit. 
     As a means to solve the above-described fourth problem, a method according to the present invention is a method for a harvester. The harvester including a vehicle body that performs harvesting operations for a crop while traveling in a field, a camera that generates a shot image, a display unit that displays an image, and a storage unit for storing vehicle body data indicating an external shape of the vehicle body. The method includes: a first compositing step of generating a first composite image based on the shot image generated by the camera and the vehicle body data stored in the storage unit, the first composite image being an image showing the vehicle body and the field around the vehicle body; a second compositing step of generating a second composite image by compositing an information presentation image indicating information related to the harvesting operations with the first composite image generated in the first compositing step at a related position, the related position being a position in the first composite image which position is related to the information presentation image; and a display control step of causing the second composite image generated in the second compositing step to be displayed in the display unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right-side view of a vehicle body of a standard combine according to a first embodiment. 
         FIG. 2  is a plan view of the vehicle body of the standard combine according to the first embodiment. 
         FIG. 3  is a left-side view of the vehicle body of the standard combine according to the first embodiment. 
         FIG. 4  is a front view of the vehicle body of the standard combine according to the first embodiment. 
         FIG. 5  is a rear view of the vehicle body of the standard combine according to the first embodiment. 
         FIG. 6  is a block diagram illustrating a control configuration according to the first embodiment. 
         FIG. 7  is a diagram illustrating an example of a composite image according to the first embodiment. 
         FIG. 8  is a diagram illustrating an example of a composite image according to the first embodiment. 
         FIG. 9  is a plan view of the vehicle body of the standard combine according to a variation on the first embodiment. 
         FIG. 10  is a right-side view of a vehicle body of a head-feeding combine according to a second embodiment. 
         FIG. 11  is a plan view of the vehicle body of the head-feeding combine according to the second embodiment. 
         FIG. 12  is a left-side view of the vehicle body of the head-feeding combine according to the second embodiment. 
         FIG. 13  is a front view of the vehicle body of the head-feeding combine according to the second embodiment. 
         FIG. 14  is a rear view of the vehicle body of the head-feeding combine according to the second embodiment. 
         FIG. 15  is a plan view of the vehicle body of the head-feeding combine according to a variation on the second embodiment. 
         FIG. 16  is a right-side view of a vehicle body of a head-feeding combine according to a third embodiment. 
         FIG. 17  is a plan view of the vehicle body of the head-feeding combine according to the third embodiment. 
         FIG. 18  is a left-side view of the vehicle body of the head-feeding combine according to the third embodiment. 
         FIG. 19  is a front view of the vehicle body of the head-feeding combine according to the third embodiment. 
         FIG. 20  is a rear view of the vehicle body of the head-feeding combine according to the third embodiment. 
         FIG. 21  is a block diagram illustrating a control configuration according to the third embodiment. 
         FIG. 22  is a diagram illustrating an example of a composite image according to the third embodiment. 
         FIG. 23  is a diagram illustrating an example of a composite image according to the third embodiment. 
         FIG. 24  is a plan view of the vehicle body of the head-feeding combine according to a variation on the third embodiment. 
         FIG. 25  is a right-side view of a vehicle body of a standard combine according to a fourth embodiment. 
         FIG. 26  is a plan view of the vehicle body of the standard combine according to the fourth embodiment. 
         FIG. 27  is a left-side view of the vehicle body of the standard combine according to the fourth embodiment. 
         FIG. 28  is a front view of the vehicle body of the standard combine according to the fourth embodiment. 
         FIG. 29  is a rear view of the vehicle body of the standard combine according to the fourth embodiment. 
         FIG. 30  is a block diagram illustrating a control configuration according to the fourth embodiment. 
         FIG. 31  is a diagram illustrating an example of a composite image according to the fourth embodiment. 
         FIG. 32  is a diagram illustrating an example of a composite image according to the fourth embodiment. 
         FIG. 33  is a right-side view of a vehicle body of a head-feeding combine according to a fifth embodiment. 
         FIG. 34  is a plan view of the vehicle body of the head-feeding combine according to the fifth embodiment. 
         FIG. 35  is a left-side view of the vehicle body of the head-feeding combine according to the fifth embodiment. 
         FIG. 36  is a front view of the vehicle body of the head-feeding combine according to the fifth embodiment. 
         FIG. 37  is a rear view of the vehicle body of the head-feeding combine according to the fifth embodiment. 
         FIG. 38  is a block diagram illustrating a control configuration according to the fifth embodiment. 
         FIG. 39  is a diagram illustrating an example of a composite image according to the fifth embodiment. 
         FIG. 40  is a block diagram illustrating a control configuration according to a sixth embodiment. 
         FIG. 41  is a diagram illustrating an example of a composite image according to the sixth embodiment. 
         FIG. 42  is a diagram illustrating an example of a composite image according to the sixth embodiment. 
         FIG. 43  is a diagram illustrating an example of a composite image according to the sixth embodiment. 
         FIG. 44  is a block diagram illustrating a control configuration according to a variation on the sixth embodiment. 
         FIG. 45  is a diagram illustrating an example of a composite image according to a variation on the sixth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     First Embodiment 
     An embodiment of the present invention will be described on the basis of the drawings. In the following descriptions, the direction of an arrow F corresponds to a “vehicle body front side”, the direction of an arrow B corresponds to a “vehicle body rear side”, the direction of an arrow L corresponds to a “vehicle body left side”, and the direction of an arrow R corresponds to a “vehicle body right side”. 
     Overall Configuration of Combine 
       FIGS. 1 to 5  illustrate a standard combine, which is an example of a harvester. A vehicle body V of this standard combine includes a vehicle body frame  1 , and a pair of crawler traveling devices  2  on the left and right sides. A mowing unit  3  (an example of a harvesting unit) that mows planted grain culm in a field is provided in a front part of the vehicle body V. The mowing unit  3  is provided with a raking reel  4  that rakes in the planted grain culm, a cutting blade  5  that cuts the planted grain culm, and a raking auger  6  that rakes in the cut grain culm. The mowing unit  3  is provided with a pair of dividers  7  on the left and right that divide the planted grain culm in the field into grain culm to be cut and grain culm not to be cut. The mowing unit  3  has a mowing width that is wider than a width of the vehicle body. A mowing frame  3   a  extending in the left-right direction is provided at a rear end part of the mowing unit  3 . 
     A driving section  8 , and a cabin  9  that encloses the driving section  8 , are provided to the rear of the mowing unit  3  in the vehicle body V. The driving section  8  is located on the right side in a front part of the vehicle body V. A feeder  10  (an example of a transport unit) that transports a harvested crop harvested by the mowing unit  3  is provided to the left of the driving section  8 . 
     A threshing device  11  that threshes the harvested crop transported by the feeder  10  is provided to the rear of the feeder  10 . The threshing device  11  includes a main body part  11   a  and a top panel  11   b  that opens and closes an opening provided in an upper surface of the main body part  11   a . A left end part of the top panel  11   b  is supported by the main body part  11   a  in a state where the top panel  11   b  can rotate about a rotation axis extending in a front-back direction. A waste straw processing device  11   c  that cuts waste straw is provided in a rear part of the threshing device  11 . 
     A grain tank  12  that stores grain obtained by the threshing device  11  is provided to the rear of the driving section  8  and to the right of the threshing device  11 . A discharge device  13  that discharges the grain stored in the grain tank  12  to outside is provided to the rear of the grain tank  12 . A rear cover part  14  that covers the grain tank  12  and the discharge device  13  from behind is provided in a rear part of the vehicle body V. 
     The discharge device  13  is provided with a vertical transport unit  13   a  connected to the grain tank  12  and extending along an up-down direction, and a horizontal transport unit  13   b  connected to an upper end of the vertical transport unit  13   a  so as to be capable of pivoting vertically. The discharge device  13  can be swiveled about a swivel axis center extending in the up-down direction. 
     A driver&#39;s seat  8   a  in which a driver sits is provided in the driving section  8 . The cabin  9  is provided with a roof part  9   a  and a cabin frame  9   b  that supports the roof part  9   a . The cabin frame  9   b  supports a windshield  9   c , a door  9   d , a side glass  9   e , and the like of the cabin  9 . 
     An engine  15  is provided below the driver&#39;s seat  8   a . A radiator  16  is provided on the opposite side of the feeder  10  to the engine  15 , i.e., to the right of the engine  15 . A dust-resistant case  17  (an example of a dust-resistant unit) that removes dust from outside air supplied to the radiator  16  is provided on the opposite side of the feeder  10  to the radiator  16 , i.e., to the right of the radiator  16 . 
     A satellite positioning module  18  that receives a GNSS (Global Navigation Satellite System) signal from a satellite and detects the self vehicle position on the basis of that signal is provided. GPS, QZSS, Galileo, GLONASS, BeiDou, or the like can be used as the GNSS. The satellite positioning module  18  is provided on the left side at the front part of the driving section  8 . The satellite positioning module  18  is provided above the roof part  9   a . 
     Cameras 
     A front camera  21 , a rear camera  22 , a right camera  23  (an example of a first side camera), and a left camera  24  (an example of a second side camera) are provided on the vehicle body V of the standard combine. These four cameras generate shot images and output the images to an image processing device  30  (described below). In the present embodiment, the four cameras mainly shoot images of fields, ridges, roads, and the like around the vehicle body V, and may also shoot images of parts of the vehicle body V. As such, part of the vehicle body V may be shown in the shot images. In the present embodiment, the shot images, a preliminary composite image (described later), and a composite image may be still images, or may be moving images and video obtained by sequentially displaying still images. Assuming an optical axis (shooting direction) is oriented in the horizontal direction, a shooting range (angle of view) of each camera is 180° or more (e.g., 195°) in the horizontal direction and 100° or more (e.g., 120°) in the vertical direction central to the optical axis. 
     Placement of Front Camera 
     As illustrated in  FIGS. 2 to 4 , the front camera  21  is provided in a front part of the driving section  8  so as to be located in a central part of the vehicle body V in the left-right direction. Specifically, the front camera  21  is provided in the front part of the driving section  8 , adjacent to the side of the threshing device  11 . In other words, the front camera  21  is placed on a left side surface of the front part of the driving section  8 . 
     The front camera  21  is supported by the cabin frame  9   b  using a stay. The roof part  9   a  provided in the driving section  8  includes a projecting part  9   f  that projects further to the left than the side glass  9   e . The front camera  21  is provided directly below the projecting part  9   f . The front camera  21  is provided at a position lower than the satellite positioning module  18 . 
     A shooting direction  21   a  of the front camera  21  is oriented diagonally downward toward the front, i.e., toward the mowing unit  3 . The front camera  21  is provided so that the entire mowing unit  3  and a region around the mowing unit  3  (part of the field) are included in a shooting range  21   b  thereof. In other words, the shooting range  21   b  of the front camera  21  includes the mowing frame  3   a , the raking reel  4 , the raking auger  6 , the dividers  7 , part of the feeder  10 , a region to the front of the mowing unit  3 , a region to the rear of the mowing unit  3 , a region to the right of the mowing unit  3 , and a region to the left of the mowing unit  3 . 
     Placement of Rear Camera 
     As illustrated in  FIGS. 1 to 3 and 5 , the rear camera  22  is provided in an upper part of the rear cover part  14  so as to be located in a central part of the vehicle body V in the left-right direction. Specifically, the rear camera  22  is provided at a left end part of the upper surface of the rear cover part  14 . The rear camera  22  is supported by the rear cover part  14  using a stay. The rear camera  22  is provided at a position lower than the satellite positioning module  18 . 
     A shooting direction  22   a  of the rear camera  22  is oriented diagonally downward toward the rear, i.e., toward the rear of the waste straw processing device  11   c . The rear camera  22  is provided so that the entire waste straw processing device  11   c  and a region around the waste straw processing device  11   c  (part of the field) are included in a shooting range  22   b  thereof. In other words, the shooting range  22   b  of the rear camera  22  includes the waste straw processing device  11   c , a region to the rear of the waste straw processing device  11   c , a region to the right of the waste straw processing device  11   c , and a region to the left of the waste straw processing device  11   c.    
     Placement of Right Camera 
     As illustrated in  FIGS. 1, 2, 4, and 5 , the right camera  23  is provided in a right side part of the driving section  8  so as to be located in a central part of the vehicle body V in the front-back direction. Specifically, the right camera  23  is provided in the rear part of the driving section  8 , adjacent on the right side. In other words, the right camera  23  is placed on a right side surface of the rear part of the driving section  8 . The right camera  23  is provided further to the rear than the driver&#39;s seat  8   a  included in the driving section  8 . 
     The right camera  23  is supported by the cabin frame  9   b  using a stay. The roof part  9   a  provided in the driving section  8  includes a projecting part  9   g  that projects further to the right than the door  9   d . The right camera  23  is provided directly below the projecting part  9   g . The right camera  23  is provided above the dust-resistant case  17 . The right camera  23  is provided at a position lower than the satellite positioning module  18 . 
     A shooting direction  23   a  of the right camera  23  is oriented diagonally downward toward the right, i.e., toward the right of the driving section  8 . The right camera  23  is provided so that a region to the right of the driving section  8 , a region to the right of the grain tank  12 , and a region to the right of the mowing unit  3  are included in a shooting range  23   b  thereof. 
     Placement of Left Camera 
     As illustrated in  FIGS. 2 to 5 , the left camera  24  is provided in a left side part of the threshing device  11  so as to be located in a central part of the vehicle body V in the front-back direction. Specifically, the left camera  24  is provided in the front part of the threshing device  11 , adjacent on the left side. In other words, the left camera  24  is placed on a left side surface of the front part of the threshing device  11 . 
     The left camera  24  is supported by the threshing device  11  using a stay. Specifically, the left camera  24  is provided on an upper part of a cover  11   d  provided on a left side part of the threshing device  11  so as to be capable of opening and closing. The left camera  24  is provided at a position lower than the satellite positioning module  18 . 
     A shooting direction  24   a  of the left camera  24  is oriented diagonally downward toward the left, i.e., toward the left of the threshing device  11 . The left camera  24  is provided so that a region to the left of the threshing device  11 , a region to the left of the feeder  10 , and a region to the left of the mowing unit  3  are included in a shooting range  24   b  thereof. 
     Image Processing Device 
     Configurations pertaining to the image processing device  30  provided in the standard combine will be described hereinafter with reference to the block diagram in  FIG. 6 . 
     The vehicle body V of the standard combine is provided with the image processing device  30  and a display unit  40 . The image processing device  30  generates a composite image on the basis of the shot images output from the front camera  21 , the rear camera  22 , the right camera  23 , and the left camera  24 , and outputs the composite image to the display unit  40 . The display unit  40  displays the composite image output by the image processing device  30 . The image processing device  30  is configured including a microcomputer, and executes image processing according to a preset program. The image processing device  30  and the display unit  40  are provided in the driving section  8 . 
     The front camera  21 , the rear camera  22 , the right camera  23 , and the left camera  24  are connected to the image processing device  30 . A front shot image from the front camera  21 , a rear shot image from the rear camera  22 , a right shot image from the right camera  23 , and a left shot image from the left camera  24  are input to the image processing device  30 . 
     A viewpoint manipulation unit  41  and a vehicle body control device  42  are connected to the image processing device  30 . The viewpoint manipulation unit  41  accepts operations for changing/specifying a viewpoint from an operator and outputs operation data to the image processing device  30 . The viewpoint manipulation unit  41  may be, for example, an implement such as a button, a knob, a joystick, or the like, or an input means such as a touch panel provided on the display unit  40 . 
     The vehicle body control device  42  outputs, to the image processing device  30 , operation state data indicating an operation state of the vehicle body V of the standard combine. The operation state data includes data indicating operation states of the vehicle body V such as moving forward, reversing, turning, stopped, and the like; data indicating operation states of the mowing unit  3  such as operating, stopped, working position, non-working position, swinging position, and the like; and data indicating operation states of the discharge device  13  such as operating, stopped, retracted position, discharge position, swivel position, and the like. 
     Implements such as a steering implement  43 , a main gearshift lever  44 , a mowing raising/lowering switch  45 , a reel raising/lowering switch  46 , a discharge implement  47 , and the like are connected to the vehicle body control device  42 . The vehicle body control device  42  generates the operation state data on the basis of operations input to these implements, and outputs the data to the image processing device  30 . Note that the vehicle body control device  42  may generate the operation state data on the basis of outputs from sensors (not shown) provided in these implements, the mowing unit  3 , the discharge device  13 , and the like. 
     The image processing device  30  includes a viewpoint determining unit  31 , a storage unit  32 , and an image compositing unit  33 . 
     On the basis of the operation data output from the viewpoint manipulation unit  41  or the operation state data input from the vehicle body control device  42 , the viewpoint determining unit  31  determines a composite viewpoint to serve as a viewpoint of the composite image generated by the image compositing unit  33 , and outputs data indicating the composite viewpoint to the image compositing unit  33  as viewpoint data. Specifically, the viewpoint determining unit  31  determines the composite viewpoint as a viewpoint of viewing the vehicle body V from directly above, a viewpoint viewing the vehicle body V from diagonally above, and a viewpoint viewing the vehicle body V from the front/rear or the left/right. The “viewpoint viewing the vehicle body V from diagonally above” is, for example, a viewpoint viewing the vehicle body V diagonally above from the front, a viewpoint viewing the vehicle body V diagonally above from the rear, a viewpoint viewing the vehicle body V diagonally above from the right, a viewpoint viewing the vehicle body V diagonally above from the left, or the like. 
     The storage unit  32  for storing vehicle body data indicating the external shape of the vehicle body V. The vehicle body data is data expressing the three-dimensional shape of the vehicle body V, e.g., data expressing a 3D model of the vehicle body V. The vehicle body data includes data expressing the external shape of the crawler traveling devices  2 , data expressing the external shape of the mowing unit  3 , and data expressing the external shape of the discharge device  13 . 
     The vehicle body data also includes data expressing the external shape of the mowing unit  3  in the working position, data expressing the external shape of the mowing unit  3  in the non-working position, data expressing the external shape of the discharge device  13  in the retracted position, and data expressing the external shape of the discharge device  13  in the discharge position. The vehicle body data is prepared in advance and stored in the storage unit  32 . 
     On the basis of the four shot images input from the front camera  21 , the rear camera  22 , the right camera  23 , and the left camera  24 , and the vehicle body data stored in the storage unit  32 , the image compositing unit  33  generates the composite image, which is an image seen from the viewpoint determined by the viewpoint determining unit  31  and showing the vehicle body V and the surroundings thereof, and outputs the composite image to the display unit  40 . Some parts of the vehicle body V captured by the cameras will appear in the composite image. However, if the viewpoint determined by the viewpoint determining unit  31  is a viewpoint from which one of those parts of the vehicle body V cannot be seen, those parts will not appear in the composite image. 
     First, the image compositing unit  33  generates the preliminary composite image by performing image processing including viewpoint conversion and compositing in the shot images from the four cameras, and converting the composite viewpoint of the viewpoint data input from the viewpoint determining unit  31  into an image. The preliminary composite image is an image obtained by compositing the shot images shot and generated by the four cameras into a single image. Planar projection transformation using homography matrices, projection processing in three-dimensional space, and the like are specific methods for the image processing. 
     Next, the image compositing unit  33  reads out the vehicle body data from the storage unit  32  and generates an image of the vehicle body V viewed from the viewpoint indicated by the viewpoint data (a vehicle body image) from the vehicle body data. At this time, referring to the operation state data input from the vehicle body control device  42 , the image compositing unit  33  generates a vehicle body image that matches the operation state using the vehicle body data based on the operation states of the mowing unit  3  and the discharge device  13 . The image compositing unit  33  then generates the composite image by compositing the preliminary composite image generated earlier with the vehicle body image. 
     Example of Composite Image 
     Assume that the standard combine is performing harvesting operations while traveling forward in a field. An example of the composite image generated by the image compositing unit  33  at this time is illustrated in  FIG. 7  as a composite image  50 . 
     The operation state of the vehicle body V at this time is that the vehicle body V is traveling straight forward, the mowing unit  3  is in the working position and is operating, and the discharge device  13  is in the retracted position and is stopped. The vehicle body control device  42  outputs, to the image processing device  30 , operation state data indicating the stated operation state of the vehicle body V. 
     Assume that the viewpoint manipulation unit  41  has accepted an operation specifying a planar viewpoint. The viewpoint manipulation unit  41  outputs operation data indicating the planar viewpoint to the viewpoint determining unit  31 . On the basis of accepting the input of the operation data, the viewpoint determining unit  31  of the image processing device  30  determines the viewpoint of the composite image composited by the image compositing unit  33  (the composite viewpoint) as the planar viewpoint, and outputs viewpoint data to that effect to the image compositing unit  33 . 
     The image compositing unit  33  generates the preliminary composite image by performing image processing including viewpoint conversion to the planar viewpoint and compositing in the shot images input from the four cameras. Next, the image compositing unit  33  generates the vehicle body image by referring to the operation state data input from the vehicle body control device  42  and the viewpoint data input from the viewpoint determining unit  31 . Specifically, the vehicle body image showing the vehicle body V from the planar viewpoint is generated using the data expressing the external shapes of the mowing unit  3  in the working position and the feeder  10 , the data expressing the external shape of the discharge device  13  in the retracted position, and the vehicle body data pertaining to remaining parts of the vehicle body V. The image compositing unit  33  then generates the composite image  50  by compositing the vehicle body image with the preliminary composite image. 
       FIG. 7  illustrates the composite image  50  generated by the image compositing unit  33 . A region  50   a  outside a boundary line E in the composite image  50  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the four cameras. The shot mowing unit  3  (the mowing frame  3   a , the raking reel  4 , the raking auger  6 , and the dividers  7 ), the feeder  10 , the waste straw processing device  11   c , the region to the rear of the mowing unit  3 , the region to the rear of the waste straw processing device  11   c , an already-mowed area H to the right and to the rear of the vehicle body V, and an unmowed area G to the left and to the front of the vehicle body V are indicated in this region  50   a . A region  50   b  inside the boundary line E in the composite image  50  is a region originating from the vehicle body image. The driving section  8 , the feeder  10 , the threshing device  11 , the grain tank  12 , the discharge device  13 , and the like are shown in the region  50   b.    
       FIG. 8  illustrates another example of the composite image  50 . As in the foregoing example, the region  50   a  outside the boundary line E in the composite image  50  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the four cameras. A region  50   b  inside the boundary line E in the composite image  50  is a region originating from the vehicle body image. In the example in  FIG. 8 , the already-mowed area H to the right and to the rear of the vehicle body V, and the unmowed area G to the left and to the front of the vehicle body V, are shown in the region  50   a . The mowing unit  3  (the mowing frame  3   a , the raking reel  4 , the raking auger  6 , and the dividers  7 ), the driving section  8 , the feeder  10 , the threshing device  11 , the waste straw processing device  11   c , the grain tank  12 , the discharge device  13 , and the like are shown in the region  50   b . 
     In other words, in the example in  FIG. 7 , the mowing unit  3 , the mowing frame  3   a , the raking reel  4 , the raking auger  6 , the dividers  7 , and the waste straw processing device  11   c  are shown, in the composite image  50 , in images captured by the front camera  21  and the rear camera  22 . In the example in  FIG. 8 , the mowing unit  3 , the mowing frame  3   a , the raking reel  4 , the raking auger  6 , the dividers  7 , and the waste straw processing device  11   c  are shown, in the composite image  50 , in an image generated on the basis of the vehicle body data (the vehicle body image). The change in the image format described above can be achieved by changing the image processing method, settings, and the like used by the image compositing unit  33 . 
     Switching Viewpoint of Composite Image 
     In the standard combine according to the present embodiment described thus far, the viewpoint of the composite image displayed in the display unit  40  can be switched at any time in response to an operation made by the driver through the viewpoint manipulation unit  41 , a change in the operation state of the vehicle body V, or the like. Specifically, in response to accepting an operation from the driver specifying a viewpoint, the viewpoint manipulation unit  41  outputs operation data indicating that viewpoint to the viewpoint determining unit  31 . In response to a change in the operation state of the vehicle body V, the vehicle body control device  42  outputs operation state data indicating the operation state of the vehicle body V to the viewpoint determining unit  31 . Each time the input of the operation data and the operation state data is accepted, the viewpoint determining unit  31  determines the composite viewpoint and outputs viewpoint data indicating the composite viewpoint to the image compositing unit  33 . The image compositing unit  33  generates the composite image so that the viewpoint of the generated composite image is the composite viewpoint indicated by the input viewpoint data, and outputs the composite image to the display unit  40 . The viewpoint of the composite image displayed in the display unit  40  can be switched in this manner. 
     The viewpoint determining unit  31  may be configured such that when determining the composite viewpoint in accordance with the operation state data input from the vehicle body control device  42 , the viewpoint determining unit  31  determines the composite viewpoint by selecting a viewpoint from a plurality of viewpoints viewing the vehicle body V diagonally from above. For example, the viewpoint determining unit  31  may be configured to determine a viewpoint viewing the vehicle body V diagonally above from the rear as the composite viewpoint in response to the input operation state data indicating that the vehicle body V is traveling forward, determine a viewpoint viewing the vehicle body V diagonally above from the front as the composite viewpoint in response to the vehicle body V traveling in reverse, and determine a viewpoint viewing the vehicle body V diagonally above from the left as the composite viewpoint in response to the discharge device  13  discharging grain. 
     Variations on First Embodiment 
     (1) In the following descriptions, configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described.  FIG. 9  illustrates another form of the standard combine. In this standard combine, the right camera  23  is provided on a right side part of the grain tank  12  so as to be located in a central part of the vehicle body V in the front-back direction. Specifically, the right camera  23  is provided in the front part of the grain tank  12 , adjacent on the right side. In other words, the right camera  23  is placed on a right side surface of the front part of the grain tank  12 . The right camera  23  is supported by the grain tank  12  using a stay. 
     The left camera  24  is provided in a front part of the threshing device  11 , on a left-side part of the top panel lib on the upper surface of the main body part  11   a , so as to be located in a central part of the vehicle body V in the front-back direction. In other words, the left camera  24  is located further to the left than the top panel lib. 
     (2) In the foregoing embodiment, the rear cover part  14  covers both the grain tank  12  and the discharge device  13  from behind, but a form in which the rear cover part  14  covers only one of the grain tank  12  and the discharge device  13  is also possible. 
     (2) In the foregoing first embodiment, four cameras are provided on the standard combine and a head-feeding combine. There may be five or more cameras. In other words, in addition to the front camera  21 , the rear camera  22 , the right camera  23 , and the left camera  24 , a camera that shoots part of the vehicle body, a camera that shoots the field below the vehicle body, or the like may be provided in the standard combine and the head-feeding combine, and shot images from those cameras may be shown in the composite image  50 . 
     Second Embodiment 
     Another embodiment of the present invention will be described on the basis of the drawings.  FIGS. 10 to 14  illustrate a head-feeding combine, which is an example of a harvester. A vehicle body W of this head-feeding combine includes a vehicle body frame  61 , and a pair of crawler traveling devices  62  on the left and right sides. A mowing unit  63  (an example of a harvesting unit) that mows planted grain culm in a field is provided in a front part of the vehicle body W. 
     A driving section  68 , and a cabin  69  that encloses the driving section  68 , are provided to the rear of the mowing unit  63  in the vehicle body W. The driving section  68  is located on the right side in a front part of the vehicle body W. A transport unit  70  that transports a harvested crop harvested by the mowing unit  63  is provided to the left of the driving section  68 . 
     A threshing device  71  that threshes the harvested crop transported by the transport unit  70  is provided to the rear of the transport unit  70 . A waste straw processing device  71   c  that cuts waste straw is provided in a rear part of the threshing device  71 . 
     A grain tank  72  that stores grain obtained by the threshing device  71  is provided to the rear of the driving section  68  and to the right of the threshing device  71 . A discharge device  73  that discharges the grain stored in the grain tank  72  to outside is provided to the rear of the grain tank  72 . 
     The discharge device  73  is provided with a vertical transport unit  73   a  connected to the grain tank  72  and extending along an up-down direction, and a horizontal transport unit  73   b  connected to an upper end of the vertical transport unit  73   a  so as to be capable of pivoting vertically. The discharge device  73  can be swiveled about a swivel axis center extending in the up-down direction. 
     A driver&#39;s seat  68   a  in which a driver sits is provided in the driving section  68 . The cabin  69  is provided with a roof part  69   a  and a cabin frame  69   b  that supports the roof part  69   a . The cabin frame  69   b  supports a windshield  69   c , a door  69   d , a side glass  69   e , and the like of the cabin  69 . 
     An engine  75  is provided below the driver&#39;s seat  68   a . A radiator  76  is provided on the opposite side of the mowing unit  63  to the engine  75 , i.e., to the right of the engine  75 . A dust-resistant case  77  (an example of a dust-resistant unit) that removes dust from outside air supplied to the radiator  76  is provided on the opposite side of the mowing unit  63  to the radiator  76 , i.e., to the right of the radiator  76 . 
     A satellite positioning module  78  that receives a GNSS (Global Navigation Satellite System) signal from a satellite and detects the self vehicle position on the basis of that signal is provided. GPS, QZSS, Galileo, GLONASS, BeiDou, or the like can be used as the GNSS. The satellite positioning module  78  is provided on the left side at the front part of the driving section  68 . The satellite positioning module  78  is provided above the roof part  69   a.    
     The mowing unit  63  is provided with a pair of dividers  63   a  on the left and right that divide the planted grain culm in the field into grain culm to be cut and grain culm not to be cut, a lifting device  63   b  that lifts the planted grain culm, a cutting blade  63   c  that cuts the planted grain culm, and a merging transport unit  63   d  that merges the cut grain culm and transports the cut grain culm to the transport unit  70 . 
     The transport unit  70  includes a first transport device  70   a  that takes the cut grain culm from the merging transport unit  63   d  of the mowing unit  63  and transports the cut grain culm toward the threshing device  71 , and a second transport device  70   b  that takes the cut grain culm from the first transport device  70   a  and transports the cut grain culm toward the threshing device  71 . The first transport device  70   a  and the second transport device  70   b  transport the base side parts of the cut grain culm. The first transport device  70   a  is configured so that the depth of processing can be adjusted by changing the attitude thereof. 
     A feed chain  70   c  that transports the cut grain culm transported by the second transport device  70   b  of the transport unit  70  to the rear, and a rail stand  70   d  that supports the cut grain culm along with the feed chain  70   c  at a position vertically opposite to the feed chain  70   c , are provided. The threshing device  71  threshes the cut grain culm transported by the feed chain  70   c.    
     Cameras 
     A front camera  81 , a rear camera  82 , a right camera  83  (an example of a first side camera), and a left camera  84  (an example of a second side camera) are provided in the vehicle body W of the head-feeding combine. These four cameras generate shot images and output the images to the image processing device  30  included in the vehicle body W. In the present embodiment, the four cameras mainly shoot images of fields, ridges, roads, and the like around the vehicle body W, and may also shoot images of parts of the vehicle body W. As such, part of the vehicle body W may be shown in the shot images. In the present embodiment, the shot images, a preliminary composite image (described later), and a composite image may be still images, or may be moving images and video obtained by sequentially displaying still images. Assuming an optical axis (shooting direction) is oriented in the horizontal direction, a shooting range (angle of view) of each camera is 180° or more (e.g., 195°) in the horizontal direction and 100° or more (e.g., 120°) in the vertical direction central to the optical axis. 
     Placement of Front Camera 
     As illustrated in  FIGS. 11 to 13 , the front camera  81  is provided in a front part of the driving section  68  so as to be located in a central part of the vehicle body W in the left-right direction. Specifically, the front camera  81  is provided in the front part of the driving section  68 , adjacent to the side of the threshing device  71 . In other words, the front camera  81  is placed on a left side surface of the front part of the driving section  68 . 
     The front camera  81  is supported by the cabin frame  69   b  using a stay. The roof part  69   a  provided in the driving section  68  includes a projecting part  69   f  that projects further to the left than the side glass  69   e . The front camera  81  is provided directly below the projecting part  69   f . The front camera  81  is provided at a position lower than the satellite positioning module  78 . 
     A shooting direction  81   a  of the front camera  81  is oriented diagonally downward toward the front, i.e., toward the mowing unit  63 . The front camera  81  is provided so that the entire mowing unit  63  and a region around the mowing unit  63  (part of the field) are included in a shooting range  81   b  thereof. In other words, the shooting range  81   b  of the front camera  81  includes the dividers  63   a , the lifting device  63   b , the merging transport unit  63   d , a region to the front of the mowing unit  63 , a region to the rear of the mowing unit  63 , a region to the right of the mowing unit  63 , and a region to the left of the mowing unit  63 . 
     Placement of Rear Camera 
     As illustrated in  FIGS. 10 to 12 and 14 , the rear camera  82  is provided in a rear part of the threshing device  71  so as to be located in a central part of the vehicle body W in the left-right direction. Specifically, the rear camera  82  is provided in a location further toward the right side on the upper surface of the waste straw processing device  71   c  of the threshing device  71 . The rear camera  82  is supported by the threshing device  71  using a stay. The rear camera  82  is provided at a position lower than the satellite positioning module  78 . 
     A shooting direction  82   a  of the rear camera  82  is oriented diagonally downward toward the rear, i.e., toward the rear of the waste straw processing device  71   c . The rear camera  82  is provided so that the entire waste straw processing device  71   c  and a region around the waste straw processing device  71   c  (part of the field) are included in a shooting range  82   b  thereof. In other words, the shooting range  82   b  of the rear camera  82  includes the waste straw processing device  71   c , a region to the rear of the waste straw processing device  71   c , a region to the right of the waste straw processing device  71   c , and a region to the left of the waste straw processing device  71   c.    
     Placement of Right Camera 
     As illustrated in  FIGS. 10, 11, 13, and 14 , the right camera  83  is provided in a right side part of the driving section  68  so as to be located in a central part of the vehicle body W in the front-back direction. Specifically, the right camera  83  is provided in the rear part of the driving section  68 , adjacent on the right side. In other words, the right camera  83  is placed on a right side surface of the rear part of the driving section  68 . The right camera  83  is provided further to the rear than the driver&#39;s seat  68   a  included in the driving section  68 . 
     The right camera  83  is supported by the cabin frame  69   b  using a stay. The roof part  69   a  provided in the driving section  68  includes a projecting part  69   g  that projects further to the right than the door  69   d . The right camera  83  is provided directly below the projecting part  69   g . The right camera  83  is provided above the dust-resistant case  77 . The right camera  83  is provided at a position lower than the satellite positioning module  78 . 
     A shooting direction  83   a  of the right camera  83  is oriented diagonally downward toward the right, i.e., toward the right of the driving section  68 . The right camera  83  is provided so that a region to the right of the driving section  68 , a region to the right of the grain tank  72 , and a region to the right of the mowing unit  63  are included in a shooting range  83   b  thereof. 
     Placement of Left Camera 
     As illustrated in  FIGS. 11 to 14 , the left camera  84  is provided in a left side part of the threshing device  71  so as to be located in a central part of the vehicle body W in the front-back direction. Specifically, the left camera  84  is provided in the front part of the threshing device  71 , adjacent on the left side. In other words, the left camera  84  is placed on a left side surface of the front part of the threshing device  71 . The left camera  84  is supported by the threshing device  71  using a stay. The left camera  84  is provided at a position lower than the satellite positioning module  78 . 
     A shooting direction  84   a  of the left camera  84  is oriented diagonally downward toward the left, i.e., toward the left of the threshing device  71 . The left camera  84  is provided so that a region to the left of the threshing device  71 , a region to the left of the transport unit  70 , and a region to the left of the mowing unit  63  are included in a shooting range  84   b  thereof. 
     Image Processing Device 
     Like the standard combine described in the first embodiment, the head-feeding combine includes the image processing device  30  and the display unit  40 . The front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84  are connected to the image processing device  30 . In the standard combine too, the composite image is generated by the image processing device  30  and displayed by the display unit  40  in the same manner as in the foregoing embodiment. 
     Variations on Second Embodiment 
     (1)  FIG. 15  illustrates another form of the head-feeding combine. In this head-feeding combine, the rear camera  82  is provided on a rear part of the grain tank  72  so as to be located in a central part of the vehicle body W in the left-right direction. Specifically, the rear camera  82  is provided in a location further toward the left side on the upper surface of the grain tank  72 . The rear camera  82  is supported by the grain tank  72  using a stay. 
     The right camera  83  is provided on a right side part of the grain tank  72  so as to be located in a central part of the vehicle body W in the front-back direction. Specifically, the right camera  83  is provided in the front part of the grain tank  72 , adjacent on the right side. In other words, the right camera  83  is placed on a right side surface of the front part of the grain tank  72 . The right camera  83  is supported by the grain tank  72  using a stay. 
     (2) In the foregoing second embodiment, four cameras are provided on the standard combine and a head-feeding combine. There may be five or more cameras. In other words, in addition to the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84 , a camera that shoots part of the vehicle body, a camera that shoots the field below the vehicle body, or the like may be provided in the standard combine and the head-feeding combine, and shot images from those cameras may be shown in the composite image  50 . 
     Third Embodiment 
     An embodiment of the present invention will be described on the basis of the drawings. Note that configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described in detail. 
     Overall Configuration of Combine 
       FIGS. 16 to 20  illustrate a head-feeding combine, which is an example of a harvester. The configuration of this head-feeding combine is the same as in the head-feeding combine of the second embodiment ( FIGS. 10 to 15 ). 
     Cameras 
     A front camera  81 , a rear camera  82 , a right camera  83  (an example of a first side camera), and a left camera  84  (an example of a second side camera) are provided in the vehicle body W of the head-feeding combine. The placements, support structures, and shooting ranges of the front camera  81  and the rear camera  82  are the same as in the second embodiment. 
     Placement of Right Camera 
     As illustrated in  FIGS. 16, 17, 19, and 20 , the right camera  83  is provided in a right side part of the driving section  68  so as to be located in a central part of the vehicle body W in the front-back direction. Specifically, the right camera  83  is provided in the rear part of the driving section  68 , adjacent on the right side. In other words, the right camera  83  is placed on a right side surface of the rear part of the driving section  68 . The right camera  83  is provided further to the rear than the driver&#39;s seat  68   a  included in the driving section  68 . The right camera  83  is provided further to the front than the grain tank  72 . The support structure and shooting range of the right camera  83  are the same as in the second embodiment. 
     Placement of Left Camera 
     As illustrated in  FIGS. 17 to 20 , the left camera  84  is provided above a receiving part A where the cut grain culm is passed from the transport unit  70  to the feed chain  70   c . Specifically, the left camera  84  is provided forward of a left-side part of a front wall  71   f  of the threshing device  71 . The left camera  84  is supported by the front wall  71   f  of the threshing device  71  using a stay. The left camera  84  is provided further to the front than the rail stand  70   d.    
     A shooting direction  84   a  of the left camera  84  is oriented diagonally downward toward the left, i.e., toward the receiving part A. The left camera  84  is provided so that the transport unit  70 , the receiving part A, a region to the left of the threshing device  71 , a region to the left of the transport unit  70 , and a region to the left of the mowing unit  63  are included in a shooting range  84   b  thereof. In other words, the left camera  84  is provided so as to be capable of shooting the receiving part A. 
     Image Processing Device 
     Like the standard combine described in the first embodiment, the head-feeding combine includes the image processing device  30  and the display unit  40 . As illustrated in  FIG. 21 , the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84  are connected to the image processing device  30 . In the standard combine too, the composite image is generated by the image processing device  30  and displayed by the display unit  40  in the same manner as in the first embodiment. 
     Example of Composite Image 
     Assume that the head-feeding combine is performing harvesting operations while traveling forward in a field. An example of the composite image generated by the image compositing unit  33  at this time is illustrated in  FIG. 22  as a composite image  90 . 
     The operation state of the vehicle body W at this time is that the vehicle body W is traveling straight forward, the mowing unit  63  is in the working position and is operating, and the discharge device  73  is in the retracted position and is stopped. The vehicle body control device  42  outputs, to the image processing device  30 , operation state data indicating the stated operation state of the vehicle body W. 
     Assume that the viewpoint manipulation unit  41  has accepted an operation specifying a planar viewpoint. The viewpoint manipulation unit  41  outputs operation data indicating the planar viewpoint to the viewpoint determining unit  31 . On the basis of accepting the input of the operation data, the viewpoint determining unit  31  of the image processing device  30  determines the viewpoint of the composite image composited by the image compositing unit  33  (the composite viewpoint) as the planar viewpoint, and outputs viewpoint data to that effect to the image compositing unit  33 . 
     The image compositing unit  33  generates the preliminary composite image by performing image processing including viewpoint conversion to the planar viewpoint and compositing in the shot images input from the four cameras. Next, the image compositing unit  33  generates the vehicle body image by referring to the operation state data input from the vehicle body control device  42  and the viewpoint data input from the viewpoint determining unit  31 . Specifically, the vehicle body image showing the vehicle body W from the planar viewpoint is generated using the data expressing the external shapes of the mowing unit  63  in the working position and the transport unit  70 , the data expressing the external shape of the discharge device  73  in the retracted position, and the vehicle body data pertaining to remaining parts of the vehicle body W. The image compositing unit  33  then generates the composite image  90  by compositing the vehicle body image with the preliminary composite image. 
       FIG. 22  illustrates the composite image  90  generated by the image compositing unit  33 . A region  90   a  outside a boundary line E in the composite image  90  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the four cameras. The mowing unit  63 , the dividers  63   a , the lifting device  63   b , a region to the rear of the lifting device  63   b  (a rear part of the mowing unit  63 ) the transport unit  70 , the receiving part A, the already-mowed area H to the right and to the rear of the vehicle body W, and the unmowed area G to the left and to the front of the vehicle body W, which have been shot, are shown in the region  90   a . A region  90   b  inside the boundary line E in the composite image  90  is a region originating from the vehicle body image. The driving section  68 , the threshing device  71 , the grain tank  72 , part of the discharge device  73 , and the like are shown in the region  90   b . 
       FIG. 23  illustrates another example of the composite image  90 . As in the foregoing example, the region  90   a  outside the boundary line E in the composite image  90  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the four cameras. A region  90   b  inside the boundary line E in the composite image  90  is a region originating from the vehicle body image. In the example in  FIG. 23 , the already-mowed area H to the right and to the rear of the vehicle body W, and the unmowed area G to the left and to the front of the vehicle body W, are shown in the region  90   a . The mowing unit  63  (the dividers  63   a  and the lifting device  63   b ), the driving section  68 , the transport unit  70 , the threshing device  71 , the grain tank  72 , the discharge device  73 , and the like are shown in the region  90   b.    
     In other words, in the example in  FIG. 22 , the mowing unit  63  (the dividers  63   a  and the lifting device  63   b ), the transport unit  70 , and the receiving part A are shown in the composite image  90  from the images captured by the front camera  81 , the rear camera  82 , and the right camera  83 . In the example in  FIG. 23 , the mowing unit  63  (the dividers  63   a  and the lifting device  63   b ) and the transport unit  70  are shown in the composite image  90  from an image generated on the basis of the vehicle body data (the vehicle body image). The change in the image format described above can be achieved by changing the image processing method, settings, and the like used by the image compositing unit  33 . 
     Switching Viewpoint of Composite Image 
     In the head-feeding combine according to the present embodiment described thus far, the viewpoint of the composite image displayed in the display unit  40  can be switched at any time in response to an operation made by the driver through the viewpoint manipulation unit  41 , a change in the operation state of the vehicle body W, or the like. Specifically, in response to accepting an operation from the driver specifying a viewpoint, the viewpoint manipulation unit  41  outputs operation data indicating that viewpoint to the viewpoint determining unit  31 . In response to a change in the operation state of the vehicle body W, the vehicle body control device  42  outputs operation state data indicating the operation state of the vehicle body W to the viewpoint determining unit  31 . Each time the input of the operation data and the operation state data is accepted, the viewpoint determining unit  31  determines the composite viewpoint and outputs viewpoint data indicating the composite viewpoint to the image compositing unit  33 . The image compositing unit  33  generates the composite image so that the viewpoint of the generated composite image is the composite viewpoint indicated by the input viewpoint data, and outputs the composite image to the display unit  40 . The viewpoint of the composite image displayed in the display unit  40  can be switched in this manner. 
     The viewpoint determining unit  31  may be configured such that when determining the composite viewpoint in accordance with the operation state data input from the vehicle body control device  42 , the viewpoint determining unit  31  determines the composite viewpoint by selecting a viewpoint from a plurality of viewpoints viewing the vehicle body W diagonally from above. For example, the viewpoint determining unit  31  may be configured to determine a viewpoint viewing the vehicle body W diagonally above from the rear as the composite viewpoint in response to the input operation state data indicating that the vehicle body W is traveling forward, determine a viewpoint viewing the vehicle body W diagonally above from the front as the composite viewpoint in response to the vehicle body W traveling in reverse, and determine a viewpoint viewing the vehicle body W diagonally above from the left as the composite viewpoint in response to the discharge device  73  discharging grain. 
     Variations on Third Embodiment 
     (1)  FIG. 24  illustrates another form of the head-feeding combine. In this head-feeding combine, the rear camera  82  is provided on a rear part of the grain tank  72  so as to be located in a central part of the vehicle body W in the left-right direction. Specifically, the rear camera  82  is provided in a location further toward the left side on the upper surface of the grain tank  72 . The rear camera  82  is supported by the grain tank  72  using a stay. 
     The right camera  83  is provided on a right side part of the grain tank  72  so as to be located in a central part of the vehicle body W in the front-back direction. Specifically, the right camera  83  is provided in the front part of the grain tank  72 , adjacent on the right side. In other words, the right camera  83  is placed on a right side surface of the front part of the grain tank  72 . The right camera  83  is supported by the grain tank  72  using a stay. 
     (2) In the foregoing embodiments, four cameras are provided on the head-feeding combine. There may be five or more cameras. In other words, in addition to the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84 , a camera that shoots part of the vehicle body, a camera that shoots the field below the vehicle body, or the like may be provided in the head-feeding combine, and shot images from those cameras may be shown in the composite image  90 . 
     (3) The foregoing embodiment described an example in which the shooting direction  84   a  is oriented diagonally downward toward the left such that the left camera  84  can shoot the receiving part A. The left camera  84  may be configured to be switchable between that state and a state in which the shooting direction  84   a  is oriented toward the left such that the receiving part A is not shot. 
     (4) In the foregoing third embodiment, four cameras are provided on the standard combine and a head-feeding combine. There may be five or more cameras. In other words, in addition to the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84 , a camera that shoots part of the vehicle body, a camera that shoots the field below the vehicle body, or the like may be provided in the standard combine and the head-feeding combine, and shot images from those cameras may be shown in the composite image  50 . 
     Fourth Embodiment 
     An embodiment of the present invention will be described on the basis of the drawings. Note that configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described in detail. 
     Overall Configuration of Combine 
       FIGS. 25 to 29  illustrate a standard combine, which is an example of a harvester. The configuration of this standard combine is the same as in the standard combine of the first embodiment ( FIGS. 1 to 5 ). 
     Cameras 
     The front camera  21  (an example of a camera), the rear camera  22  (an example of a camera), the right camera  23  (an example of a camera), the left camera  24  (an example of a camera), a lower-right camera  25  (an example of a camera and a lower camera), a lower-left camera  26  (an example of a camera and a lower camera), and a lower-rear camera  27  (an example of a camera and a lower camera) are provided in the vehicle body V of the standard combine. These seven cameras generate shot images and output the images to an image processing device  30  (described below). In the present embodiment, the seven cameras mainly shoot images of fields, ridges, roads, and the like around the vehicle body V, and may also shoot images of parts of the vehicle body V. As such, part of the vehicle body V may be shown in the shot images. 
     The placements, support structures, and shooting ranges of the front camera  21 , the rear camera  22 , the right camera  23 , and the left camera  24  are the same as in the first embodiment. 
     Placement of Lower-Right Camera 
     As illustrated in  FIG. 25 , the lower-right camera  25  is provided in a position of the vehicle body V lower than the front camera  21 . Specifically, the lower-right camera  25  is provided in a right-side part of the front part of the vehicle body frame  1 . The lower-right camera  25  is located further to the right than the front camera  21 . The lower-right camera  25  is located further to the front and to the left than the right crawler traveling device  2 . The lower-right camera  25  is supported by the vehicle body frame  1  using a stay. 
     A shooting direction  25   a  of the lower-right camera  25  is oriented diagonally downward toward the right, i.e., toward the right crawler traveling device  2 . The lower-right camera  25  is provided so that a lower part of the vehicle body V and the field below the vehicle body V are included in a shooting range  25   b  thereof. Specifically, a front part of the right crawler traveling device  2  and the field around the right crawler traveling device  2  are included in the shooting range  25   b  of the lower-right camera  25 . 
     Placement of Lower-Left Camera 
     As illustrated in  FIG. 27 , the lower-left camera  26  is provided in a position of the vehicle body V lower than the front camera  21 . Specifically, the lower-left camera  26  is provided in a left-side part of the front part of the vehicle body frame  1 . The lower-left camera  26  is located further to the left than the front camera  21 . The lower-left camera  26  is located further to the front and to the right than the left crawler traveling device  2 . The lower-left camera  26  is supported by the vehicle body frame  1  using a stay. 
     A shooting direction  26   a  of the lower-left camera  26  is oriented diagonally downward toward the left, i.e., toward the left crawler traveling device  2 . The lower-left camera  26  is provided so that a lower part of the vehicle body V and the field below the vehicle body V are included in a shooting range  26   c  thereof. Specifically, a front part of the left crawler traveling device  2  and the field around the left crawler traveling device  2  are included in the shooting range  26   c  of the lower-left camera  26 . 
     Placement of Lower-Rear Camera 
     As illustrated in  FIGS. 25, 27, and 29 , the lower-rear camera  27  is provided in a position of the vehicle body V lower than the front camera  21 . Specifically, the lower-rear camera  27  is provided in a rear part of the vehicle body frame  1  so as to be located in a central part of the vehicle body V in the left-right direction. The lower-rear camera  27  is located in a position lower than the waste straw processing device  11   c . The lower-rear camera  27  is supported by the vehicle body frame  1  using a stay. 
     A shooting direction  27   a  of the lower-rear camera  27  is oriented diagonally downward toward the rear, i.e., toward the field to the rear of the vehicle body V. The lower-rear camera  27  is provided so that a lower part of the vehicle body V, the field below the vehicle body V, and the field to the rear of the vehicle body V are included in a shooting range  27   b  thereof. Specifically, a lower part of the waste straw processing device  11   c , the field below the waste straw processing device  11   c , and the field to the rear of the waste straw processing device  11   c  are included in the shooting range  27   b  of the lower-rear camera  27 . 
     Image Processing Device 
     Like the standard combine described in the first embodiment, the standard combine according to the present embodiment includes the image processing device  30  and the display unit  40 . As illustrated in  FIG. 30 , the front camera  21 , the rear camera  22 , the right camera  23 , the left camera  24 , the lower-right camera  25 , the lower-left camera  26 , and the lower-rear camera  27  are connected to the image processing device  30 . A front shot image from the front camera  21 , a rear shot image from the rear camera  22 , a right shot image from the right camera  23 , and a left shot image from the left camera  24  are input to the image processing device  30 . A lower-right shot image from the lower-right camera  25 , a lower-left shot image from the lower-left camera  26 , and a lower-rear shot image from the lower-rear camera  27  are input to the image processing device  30 . In the standard combine according to the present embodiment too, the composite image is generated by the image processing device  30  and displayed by the display unit  40  in the same manner as in the first embodiment. 
     The storage unit  32  for storing vehicle body data indicating the external shape of the vehicle body V. The vehicle body data is data expressing the three-dimensional shape of the vehicle body V, e.g., data expressing a 3D model of the vehicle body V. The vehicle body data includes data expressing the external shape of the crawler traveling devices  2 , data expressing the external shape of the mowing unit  3 , data expressing the external shape of the discharge device  13 , and data expressing the external shape of the waste straw processing device  11   c.    
     Example of Composite Image 
     Assume that the standard combine is performing harvesting operations while traveling forward in a field. An example of the composite image generated by the image compositing unit  33  at this time is illustrated in  FIG. 31  as a composite image  150 . 
     The operation state of the vehicle body V at this time is that the vehicle body V is traveling straight forward, the mowing unit  3  is in the working position and is operating, and the discharge device  13  is in the retracted position and is stopped. The vehicle body control device  42  outputs, to the image processing device  30 , operation state data indicating the stated operation state of the vehicle body V. 
     Assume that the viewpoint manipulation unit  41  has accepted an operation specifying a planar viewpoint. The viewpoint manipulation unit  41  outputs operation data indicating the planar viewpoint to the viewpoint determining unit  31 . On the basis of accepting the input of the operation data, the viewpoint determining unit  31  of the image processing device  30  determines the viewpoint of the composite image composited by the image compositing unit  33  (the composite viewpoint) as the planar viewpoint, and outputs viewpoint data to that effect to the image compositing unit  33 . 
     The image compositing unit  33  generates the preliminary composite image by performing image processing including viewpoint conversion to the planar viewpoint and compositing in the shot images input from the seven cameras. Next, the image compositing unit  33  generates the vehicle body image by referring to the operation state data input from the vehicle body control device  42  and the viewpoint data input from the viewpoint determining unit  31 . Specifically, the vehicle body image showing the vehicle body V from the planar viewpoint is generated using the data expressing the external shapes of the mowing unit  3  in the working position and the feeder  10 , the data expressing the external shape of the discharge device  13  in the retracted position, and the vehicle body data pertaining to remaining parts of the vehicle body V. The image compositing unit  33  then generates the composite image  150  by compositing the vehicle body image with the preliminary composite image. 
       FIG. 31  illustrates the composite image  150  generated by the image compositing unit  33 . A region  150   a  outside a boundary line E in the composite image  150  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the seven cameras. The shot mowing unit  3  (the mowing frame  3   a , the raking reel  4 , the raking auger  6 , and the dividers  7 ), the feeder  10 , the waste straw processing device  11   c , the region to the rear of the mowing unit  3 , the region to the rear of the waste straw processing device  11   c , an already-mowed area H to the right and to the rear of the vehicle body V, and an unmowed area G to the left and to the front of the vehicle body V are indicated in this region  150   a . A region  150   b  inside the boundary line E in the composite image  150  is a region originating from the vehicle body image. The driving section  8 , the feeder  10 , the threshing device  11 , the grain tank  12 , the discharge device  13 , and the like are shown in the region  150   b . In this example, the left and right crawler traveling devices  2 , the field below the vehicle body V, and the field below the top panel lib are not shown in the composite image  150 . 
       FIG. 32  illustrates another example of the composite image  150 . As in the foregoing example, the region  150   a  outside the boundary line E in the composite image  150  is an image originating mainly from the preliminary composite image, and is an image originating from the shot images shot by the seven cameras. The region  150   b  inside the boundary line E in the composite image  150  is a region originating mainly from the vehicle body image. 
     In the example in  FIG. 32 , the shot mowing unit  3  (the mowing frame  3   a , the raking reel  4 , the raking auger  6 , and the dividers  7 ), the feeder  10 , the region to the rear of the mowing unit  3 , the region to the rear of the waste straw processing device  11   c , an already-mowed area H to the right and to the rear of the vehicle body V, and an unmowed area G to the left and to the front of the vehicle body V are indicated in this region  150   a . The front part of the crawler traveling devices  2  and the field around the crawler traveling devices  2  (the field below the vehicle body V), shot by the lower-right camera  25  and the lower-left camera  26 , are shown in the region  150   a . The field below the waste straw processing device  11   c , the field to the rear of the waste straw processing device  11   c , and already-cut waste straw M discharged from the waste straw processing device  11   c , shot by the lower-rear camera  27 , are shown in the region  150   a . In the region  150   a , the external shape of the waste straw processing device  11   c  generated from the vehicle body data is shown in a semi-transparent form. 
     An external shape  2   a  of the rear parts of the crawler traveling devices  2 , generated from the vehicle body data, is shown in the region  150   b.    
     In other words, in the example in  FIG. 31 , the external shapes of the driving section  8 , the feeder  10 , the threshing device  11 , the grain tank  12 , the discharge device  13 , and the like, generated from the vehicle body data, are shown in the composite image  150 . On the other hand, in the example in  FIG. 32 , instead of these external shape, the lower part of the vehicle body frame  1  (the front part of the crawler traveling devices  2 ) which has been shot, the field below the vehicle body frame  1  which has been shot, and the external shape  2   a  of the rear part of the crawler traveling devices  2  generated from the vehicle body data, are shown. The change in the image format described above can be achieved by changing the image processing method, settings, and the like used by the image compositing unit  33 . 
     Switching Viewpoint of Composite Image 
     In the standard combine according to the present embodiment described thus far, the viewpoint of the composite image displayed in the display unit  40  can be switched at any time in response to an operation made by the driver through the viewpoint manipulation unit  41 , a change in the operation state of the vehicle body V, or the like. Specifically, in response to accepting an operation from the driver specifying a viewpoint, the viewpoint manipulation unit  41  outputs operation data indicating that viewpoint to the viewpoint determining unit  31 . In response to a change in the operation state of the vehicle body V, the vehicle body control device  42  outputs operation state data indicating the operation state of the vehicle body V to the viewpoint determining unit  31 . Each time the input of the operation data and the operation state data is accepted, the viewpoint determining unit  31  determines the composite viewpoint and outputs viewpoint data indicating the composite viewpoint to the image compositing unit  33 . The image compositing unit  33  generates the composite image so that the viewpoint of the generated composite image is the composite viewpoint indicated by the input viewpoint data, and outputs the composite image to the display unit  40 . The viewpoint of the composite image displayed in the display unit  40  can be switched in this manner. 
     The viewpoint determining unit  31  may be configured such that when determining the composite viewpoint in accordance with the operation state data input from the vehicle body control device  42 , the viewpoint determining unit  31  determines the composite viewpoint by selecting a viewpoint from a plurality of viewpoints viewing the vehicle body V diagonally from above. For example, the viewpoint determining unit  31  may be configured to determine a viewpoint viewing the vehicle body V diagonally above from the rear as the composite viewpoint in response to the input operation state data indicating that the vehicle body V is traveling forward, determine a viewpoint viewing the vehicle body V diagonally above from the front as the composite viewpoint in response to the vehicle body V traveling in reverse, and determine a viewpoint viewing the vehicle body V diagonally above from the left as the composite viewpoint in response to the discharge device  13  discharging grain. 
     Variations on Fourth Embodiment 
     (1) The foregoing embodiment described an example in which the vehicle body V of the standard combine is provided with seven cameras. The number of cameras is not limited thereto, however, and two to six, or eight or more, cameras may be provided in the vehicle body V, depending on the combination of the front camera  21  and other cameras. 
     (2) In the foregoing embodiment, the entire mowing unit  3  (the entire mowing frame  3   a , the entire raking reel  4 , the entire raking auger  6 , and the entire left and right dividers  7 ) is included in the shooting range  21   b  of the front camera  21 , but the front camera  21  may be arranged such that part of the mowing unit  3  (part of the mowing frame  3   a . part of the raking reel  4 , part of the raking auger  6 , and part of the left and right dividers  7 ) is included in the shooting range  21   b  of the front camera  21 . In particular, the front camera  21  may be arranged such that all or part of the left divider  7 , of the left and right dividers  7 , is included in the shooting range  21   b  of the front camera  21 . 
     (3) In the foregoing embodiment, the entire waste straw processing device  11   c  is included in the shooting range  22   b  of the rear camera  22 , but the rear camera  22  may be arranged such that part of the waste straw processing device  11   c  is included in the shooting range  22   b  of the rear camera  22 . 
     Fifth Embodiment 
     An embodiment of the present invention will be described on the basis of the drawings. Note that configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described in detail. 
     Overall Configuration of Combine 
       FIGS. 33 to 37  illustrate a head-feeding combine, which is an example of a harvester. The configuration of this head-feeding combine is the same as in the head-feeding combine of the second embodiment ( FIGS. 10 to 14 ). 
     Cameras 
     The front camera  81  (an example of a camera), the rear camera  82  (an example of a camera), the right camera  83  (an example of a camera), the left camera  84  (an example of a camera), and a lower-left camera  86  (an example of a camera and a lower camera) are provided in the vehicle body W of the head-feeding combine. These five cameras generate shot images and output the images to the image processing device  30  included in the vehicle body W. In the present embodiment, the five cameras mainly shoot images of fields, ridges, roads, and the like around the vehicle body W, and may also shoot images of parts of the vehicle body W. As such, part of the vehicle body W may be shown in the shot images. 
     The placements, support structures, and shooting ranges of the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84  are the same as in the first embodiment. 
     Placement of Lower-Left Camera 
     As illustrated in  FIGS. 34, 35, and 37 , the lower-left camera  86  is provided in a position of the vehicle body W lower than the front camera  81 . Specifically, the lower-left camera  86  is provided in a left side part of the threshing device  71  so as to be located in what is substantially a central part of the vehicle body W in the front-back direction. The lower-left camera  86  is provided in the front part of the threshing device  71 , adjacent on the left side. In other words, the lower-left camera  86  is placed on a left side surface of the front part of the threshing device  71 . The lower-left camera  86  is supported by the threshing device  71  using a stay. The lower-left camera  86  is provided at a position lower than the satellite positioning module  78 . The lower-left camera  86  is located to the rear and lower than the left camera  84 . 
     A shooting direction  86   a  of the lower-left camera  86  is oriented diagonally downward toward the left, i.e., toward the left of the threshing device  71 . The lower-left camera  86  is provided so that a region to the left of the threshing device  71 , a region to the left of the transport unit  70 , and a region to the left of the mowing unit  63  are included in a shooting range  86   c  thereof. The lower-left camera  86  is provided such that a region below the feed chain  70   c  (part of the vehicle body W, the field, and the like) is included in the shooting range  86   c.    
     Image Processing Device 
     Like the head-feeding combine described in the first embodiment, the standard combine according to the present embodiment includes the image processing device  30  and the display unit  40 . As illustrated in  FIG. 38 , the front camera  81 , the rear camera  82 , the right camera  83 , the left camera  84 , and the lower-left camera  86  are connected to the image processing device  30 . A front shot image from the front camera  81 , a rear shot image from the rear camera  82 , a right shot image from the right camera  83 , and a left shot image from the left camera  84  are input to the image processing device  30 . A lower-left shot image from the lower-left camera  86  is input into the image processing device  30 . In the head-feeding combine according to the present embodiment too, the composite image is generated by the image processing device  30  and displayed by the display unit  40  in the same manner as in the first embodiment. 
     The storage unit  32  for storing vehicle body data indicating the external shape of the vehicle body W. The vehicle body data is data expressing a three-dimensional shape of the vehicle body W, and is, for example, data expressing a 3D model of the vehicle body W. The vehicle body data includes data expressing the external shape of the crawler traveling devices  62 , data expressing the external shape of the mowing unit  63 , data expressing the external shape of the discharge device  73 , and data expressing the external shape of the waste straw processing device  71   c.    
     Example of Composite Image 
     Assume that the head-feeding combine is performing harvesting operations while traveling forward in a field. An example of the composite image generated by the image compositing unit  33  at this time is illustrated in  FIG. 39  as a composite image  190 . 
     The operation state of the vehicle body W at this time is that the vehicle body W is traveling straight forward, the mowing unit  63  is in the working position and is operating, and the discharge device  73  is in the retracted position and is stopped. The vehicle body control device  42  outputs, to the image processing device  30 , operation state data indicating the stated operation state of the vehicle body W. 
     Assume that the viewpoint manipulation unit  41  has accepted an operation specifying a planar viewpoint. The viewpoint manipulation unit  41  outputs operation data indicating the planar viewpoint to the viewpoint determining unit  31 . On the basis of accepting the input of the operation data, the viewpoint determining unit  31  of the image processing device  30  determines the viewpoint of the composite image composited by the image compositing unit  33  (the composite viewpoint) as the planar viewpoint, and outputs viewpoint data to that effect to the image compositing unit  33 . 
     The image compositing unit  33  generates the preliminary composite image by performing image processing including viewpoint conversion to the planar viewpoint and compositing in the shot images input from the five cameras. Next, the image compositing unit  33  generates the vehicle body image by referring to the operation state data input from the vehicle body control device  42  and the viewpoint data input from the viewpoint determining unit  31 . Specifically, the vehicle body image showing the vehicle body W from the planar viewpoint is generated using the data expressing the external shapes of the mowing unit  63  in the working position and the transport unit  70 , the data expressing the external shape of the discharge device  73  in the retracted position, and the vehicle body data pertaining to remaining parts of the vehicle body W. The image compositing unit  33  then generates the composite image  190  by compositing the vehicle body image with the preliminary composite image. 
       FIG. 39  illustrates the composite image  190  generated by the image compositing unit  33 . A region  190   a  outside a boundary line E in the composite image  190  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the five cameras. The mowing unit  63  (the dividers  63   a  and the lifting device  63   b ), a region to the rear of the lifting device  63   b  (the rear part of the mowing unit  63 ), the already-mowed area H to the right and to the rear of the vehicle body W, and the unmowed area G to the left and to the front of the vehicle body W, which have been shot, are shown in the region  190   a . In particular, the unmowed area G of the field, which is a region below the feed chain  70   c  and shot by the lower-left camera  86 , is shown in the region  190   a  of the composite image  190 . A region  190   b  inside the boundary line E in the composite image  190  is a region originating from the vehicle body image. The driving section  68 , the transport unit  70 , the threshing device  71 , the grain tank  72 , the discharge device  73 , and the like are shown in the region  190   b.    
     Switching Viewpoint of Composite Image 
     In the head-feeding combine according to the present embodiment described thus far, the viewpoint of the composite image displayed in the display unit  40  can be switched at any time in response to an operation made by the driver through the viewpoint manipulation unit  41 , a change in the operation state of the vehicle body W, or the like. Specifically, in response to accepting an operation from the driver specifying a viewpoint, the viewpoint manipulation unit  41  outputs operation data indicating that viewpoint to the viewpoint determining unit  31 . In response to a change in the operation state of the vehicle body W, the vehicle body control device  42  outputs operation state data indicating the operation state of the vehicle body W to the viewpoint determining unit  31 . Each time the input of the operation data and the operation state data is accepted, the viewpoint determining unit  31  determines the composite viewpoint and outputs viewpoint data indicating the composite viewpoint to the image compositing unit  33 . The image compositing unit  33  generates the composite image so that the viewpoint of the generated composite image is the composite viewpoint indicated by the input viewpoint data, and outputs the composite image to the display unit  40 . The viewpoint of the composite image displayed in the display unit  40  can be switched in this manner. 
     The viewpoint determining unit  31  may be configured such that when determining the composite viewpoint in accordance with the operation state data input from the vehicle body control device  42 , the viewpoint determining unit  31  determines the composite viewpoint by selecting a viewpoint from a plurality of viewpoints viewing the vehicle body W diagonally from above. For example, the viewpoint determining unit  31  may be configured to determine a viewpoint viewing the vehicle body W diagonally above from the rear as the composite viewpoint in response to the input operation state data indicating that the vehicle body W is traveling forward, determine a viewpoint viewing the vehicle body W diagonally above from the front as the composite viewpoint in response to the vehicle body W traveling in reverse, and determine a viewpoint viewing the vehicle body W diagonally above from the left as the composite viewpoint in response to the discharge device  73  discharging grain. 
     Variations on Fifth Embodiment 
     (1) The foregoing embodiment described an example in which the vehicle body W of the head-feeding combine is provided with five cameras. The number of cameras is not limited thereto, however, and two to four, or six or more, cameras may be provided in the vehicle body W, depending on the combination of the front camera  81  and other cameras. 
     (2) In the foregoing embodiment, the entire mowing unit  63  (the entire left and right dividers  63   a  and the entire lifting device  63   b ) is included in the shooting range  81   b  of the front camera  81 , but the front camera  81  may be arranged such that part of the mowing unit  63  (part of the left and right dividers  63   a  and part of the lifting device  63   b ) is included in the front camera  81  of the front camera  81 . In particular, the front camera  81  may be arranged such that all or part of the left divider  63   a . of the left and right dividers  63   a . is included in the shooting range  81   b  of the front camera  81 . 
     (3) In the foregoing embodiment, the entire waste straw processing device  71   c  is included in the shooting range  82   b  of the rear camera  82 , but the rear camera  82  may be arranged such that part of the waste straw processing device  71   c  is included in the shooting range  82   b  of the rear camera  82 . 
     (4) The vehicle body W of the head-feeding combine may be provided with a camera that includes a lower part of the vehicle body W in the shooting range. For example, the vehicle body W may be provided with a camera that includes a front part (or all) of the crawler traveling devices  62 , the field below the vehicle body W, and the like in the shooting range. The vehicle body W may be provided with a camera that includes a lower part of the waste straw processing device  71   c , the field below the waste straw processing device  71   c , the field to the rear of the waste straw processing device  71   c , and the like in the shooting range. 
     Sixth Embodiment 
     An embodiment of the present invention will be described on the basis of the drawings. Note that configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described in detail. 
     Overall Configuration of Combine 
     A head-feeding combine according to the present embodiment has the same configuration as the head-feeding combine according to the second embodiment (FIGS.  10  to  14 ), and includes the display unit  40  as in the first embodiment, as well as an image processing device  230  illustrated in  FIG. 40 . 
     Image Processing Device 
     Configurations pertaining to the image processing device  230  provided in the head-feeding combine will be described hereinafter with reference to the block diagram in  FIG. 40 . 
     The vehicle body W of the head-feeding combine is provided with the image processing device  230  and the display unit  40 . The image processing device  230  generates a first composite image and a second composite image on the basis of the shot images output from the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84 , and outputs the composite images to the display unit  40 . The display unit  40  selectively displays one of the first composite image and the second composite image output by the image processing device  230  in accordance with an operation made by the driver. The image processing device  230  is configured including a microcomputer, and executes image processing according to a preset program. The image processing device  230  and the display unit  40  are provided in the driving section  68 . 
     The front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84  are connected to the image processing device  230 . A front shot image from the front camera  81 , a rear shot image from the rear camera  82 , a right shot image from the right camera  83 , and a left shot image from the left camera  84  are input to the image processing device  230 . 
     A viewpoint manipulation unit  41  and a vehicle body control device  42  are connected to the image processing device  230 . The viewpoint manipulation unit  41  accepts operations for changing/specifying a viewpoint from an operator and outputs operation data to the image processing device  230 . The viewpoint manipulation unit  41  may be, for example, an implement such as a button, a knob, a joystick, or the like, or an input means such as a touch panel provided on the display unit  40 . 
     The vehicle body control device  42  outputs, to the image processing device  230 , operation state data indicating an operation state of the vehicle body W of the head-feeding combine and harvested crop data indicating a state of the harvested crop. Implements such as a steering implement  43 , a main gearshift lever  44 , a mowing raising/lowering switch  45 , and a discharge implement  47 , as well as a yield sensor  48 , a quality sensor  49 , and the satellite positioning module  78  are connected to the vehicle body control device  42 . The vehicle body control device  42  generates the operation state data on the basis of signals from these implements, the yield sensor  48 , the quality sensor  49 , and the satellite positioning module  78 , and outputs the generated data to the image processing device  230 . 
     The yield sensor  48  is provided in the grain tank  72 , measures a weight per unit of time of grain (an example of a harvested crop) fed into the grain tank  72 , and outputs the weight to the vehicle body control device  42 . For example, the yield sensor  48  is a force sensor provided at a feed inlet where the grain is fed from the threshing device  71  into the grain tank  72 , and detects a force received from the grain fed into the grain tank  72 . 
     The quality sensor  49  is provided in the grain tank  72 , measures a quality (e.g., moisture content, protein content, or the like) of the grain fed into the grain tank  72 , and outputs the quality to the vehicle body control device  42 . For example, the quality sensor  49  is an optical analysis device, provided near the feed inlet where grain is fed from the threshing device  71  into the grain tank  72 , which temporarily stores a portion of the grain fed into the grain tank  72  and measures the quality, such as the moisture content, protein content, or the like, through spectroscopy. 
     The operation state data includes data indicating operation states of the vehicle body W such as moving forward, reversing, turning, stopped, and the like; data indicating operation states of the mowing unit  63  such as operating, stopped, working position, non-working position, swinging position, and the like; and data indicating operation states of the discharge device  73  such as operating, stopped, retracted position, discharge position, swivel position, and the like. 
     The operation state data includes data indicating a travel speed and a self vehicle position of the vehicle body W. The vehicle body control device  42  calculates the travel speed and the self vehicle position from the signals from the steering implement  43  and the main gearshift lever  44 , the self vehicle position and a change over time thereof input from the satellite positioning module  78 , and the output of a speed sensor (not shown) installed in the crawler traveling devices  62 , and generates the operation state data. 
     The operation state data includes data indicating a stored amount in the grain tank  72 . On the basis of the output from a stored amount sensor (not shown) provided in the grain tank  72 , the vehicle body control device  42  detects the stored amount in the grain tank  72  and generates the operation state data. 
     The operation state data includes data indicating a target path of the vehicle body W. On the basis of a work travel route set in advance and the self vehicle position input from the satellite positioning module  78 , the vehicle body control device  42  determines the target path (a target travel direction) and generates the operation state data. Note that the work travel route may be input by the driver before harvesting operations, or may be generated automatically on the basis of a field map. 
     The operation state data includes data indicating an event occurring during harvesting operations. The “event occurring during harvesting operations” is, for example, an abnormal noise, a malfunction, or the like occurring in the crawler traveling devices  62 , the mowing unit  63 , the transport unit  70 , the threshing device  71 , the grain tank  72 , the discharge device  73 , or the like; operations stopping due to the grain tank  72  becoming full; the execution of discharge operations from the discharge device  73 ; or the like. The vehicle body control device  42  generates data indicating the type of the event, the location in the field where the event occurred, the time when the event occurrence, and the like on the basis of signals from the connected implements, sensors provided in the vehicle body W, the self vehicle position input from the satellite positioning module  78 , and the like, and sends the data to the image processing device  230  as the operation state data. 
     The harvested crop data includes data indicating a state of the grain obtained by the threshing device  71  and stored in the grain tank  72 . On the basis of a measurement value for the yield of the grain input from the yield sensor  48 , a measurement value for the quality of the grain input from the quality sensor  49 , and the self vehicle position input from the satellite positioning module  78 , the vehicle body control device  42  generates data in which the position where the grain was harvested is associated with the yield and quality at that position, and sends the data to the image processing device  230  as the harvested crop data. For example, the vehicle body control device  42  divides the field into rectangular subregions, generates data in which average values of the yield and quality of the grain harvested in the subregions are associated with the locations of the subregions, and sends the data to the image processing device  230  as the harvested crop data. The “subregion” is a region obtained by virtually dividing the field, and is, for example, a region that is rectangular in plan view. 
     The image processing device  230  includes a viewpoint determining unit  231 , a storage unit  232 , a first compositing unit  233 , an obstruction recognizing unit  234 , a field analyzing unit  235 , and a second compositing unit  236 . 
     On the basis of the operation data output from the viewpoint manipulation unit  41  or the operation state data sent from the vehicle body control device  42 , the viewpoint determining unit  231  determines a composite viewpoint to serve as a viewpoint of the first composite image generated by the first compositing unit  233 , and outputs data indicating the composite viewpoint to the first compositing unit  233  as viewpoint data. Specifically, the viewpoint determining unit  231  determines the composite viewpoint as a viewpoint of viewing the vehicle body W from directly above, a viewpoint viewing the vehicle body W from diagonally above, and a viewpoint viewing the vehicle body W from the front/rear or the left/right. The “viewpoint viewing the vehicle body W from diagonally above” is, for example, a viewpoint viewing the vehicle body W diagonally above from the front, a viewpoint viewing the vehicle body W diagonally above from the rear, a viewpoint viewing the vehicle body W diagonally above from the right, a viewpoint viewing the vehicle body W diagonally above from the left, or the like. 
     The storage unit  232  for storing vehicle body data indicating the external shape of the vehicle body W. The vehicle body data is data expressing a three-dimensional shape of the vehicle body W, and is, for example, data expressing a 3D model of the vehicle body W. The vehicle body data includes data expressing the external shape of the crawler traveling devices  62 , data expressing the external shape of the mowing unit  63 , and data expressing the external shape of the discharge device  73 . 
     The vehicle body data also includes data expressing the external shape of the mowing unit  63  in the working position, data expressing the external shape of the mowing unit  63  in the non-working position, data expressing the external shape of the discharge device  73  in the retracted position, and data expressing the external shape of the discharge device  73  in the discharge position. The vehicle body data is prepared in advance and stored in the storage unit  232 . 
     On the basis of the four shot images input from the front camera  81 , the rear camera  82 , the right camera  83 , and the left camera  84 , and the vehicle body data stored in the storage unit  232 , the first compositing unit  233  generates the first composite image, which is an image seen from the viewpoint determined by the viewpoint determining unit  231  and showing the vehicle body W and the surroundings thereof, and outputs the first composite image to the second compositing unit  236 . Some parts of the vehicle body W captured by the cameras will appear in the first composite image. However, if the viewpoint determined by the viewpoint determining unit  231  is a viewpoint from which one of those parts of the vehicle body W cannot be seen, those parts will not appear in the first composite image. 
     Specifically, the first compositing unit  233  generates a preliminary composite image by performing image processing including viewpoint conversion and compositing in the shot images from the four cameras, and converting the composite viewpoint of the viewpoint data input from the viewpoint determining unit  231  into an image. The preliminary composite image is an image obtained by compositing the shot images shot and generated by the four cameras into a single image. Planar projection transformation using homography matrices, projection processing in three-dimensional space, and the like are specific methods for the image processing. 
     Next, the first compositing unit  233  reads out the vehicle body data from the storage unit  232  and generates an image of the vehicle body W viewed from the viewpoint indicated by the viewpoint data (a vehicle body image) from the vehicle body data. At this time, referring to the operation state data received from the vehicle body control device  42 , the first compositing unit  233  generates a vehicle body image that matches the operation state using the vehicle body data based on the operation states of the mowing unit  63  and the discharge device  73 . The first compositing unit  233  then generates the first composite image by compositing the preliminary composite image generated earlier with the vehicle body image. 
     The obstruction recognizing unit  234  analyzes the preliminary composite image generated by the first compositing unit  233  and detects the presence of an obstruction (a person, an animal, a farm tool, a ridge, or the like). Upon detecting an obstruction in the preliminary composite image, the obstruction recognizing unit  234  generates obstruction data indicating the type and position in the preliminary composite image or the obstruction, and outputs the data to the second compositing unit  236 . The obstruction recognizing unit  234  may be configured to detect the presence of obstructions by analyzing the four shot images input from the front camera  81 , rear camera  82 , right camera  83 , and left camera  84 . 
     The field analyzing unit  235  analyzes the preliminary composite image generated by the first compositing unit  233  and detects the states of the subregions, which are partial regions of the field. The “subregion” is a region obtained by virtually dividing the field, and is, for example, a region that is rectangular in plan view. The state of a subregion is, for example, whether the subregion is a region in which the crop has already been harvested (an already-mowed area) or a region in which the crop has not yet been harvested (an unmowed area), whether or not the crop in the subregion has fallen, the growth state of the crop in the subregion, and so on. Upon analyzing the preliminary composite image and detecting the state of a subregion, the field analyzing unit  235  generates field data expressing the state of that subregion and the location of the subregion in the preliminary composite image, and outputs the data to the second compositing unit  236 . Note that the field analyzing unit  235  may be configured to detect the states of subregions by analyzing the four shot images input from the front camera  81 , rear camera  82 , right camera  83 , and left camera  84 . 
     The second compositing unit  236  generates a second composite image by compositing an information presentation image with the first composite image generated by the first compositing unit  233  at a related position in the first composite image. The second compositing unit  236  then outputs the second composite image to the display unit  40 . In other words, the second compositing unit  236  is a display control unit that causes the second composite image to be displayed in the display unit  40 . The information presentation image is an image indicating information related to harvesting operations. The related position is a position in the first composite image which position is related to the information presentation image. 
     For example, the information presentation image is an image that alerts the driver to the presence of an obstruction in the field. In this case, the related position is a position in the first composite image which position corresponds to the position of the obstruction or the vicinity thereof. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the type of the obstruction from the storage unit  232  on the basis of the obstruction data input from the obstruction recognizing unit  234 , and compositing the information presentation image at the related position in the first composite image which position corresponds to the position of the obstruction (or the vicinity thereof). In the example of a second composite image  290  illustrated in  FIG. 8 , a circular information presentation image  291   n  and an information presentation image  291   p  in the shape of an exclamation point are shown in a related position corresponding to a position in the vicinity of a person (an obstruction) located diagonally to the right and the front of the vehicle body W. An information presentation image  291 q expressed as diagonal hatching is shown superimposed on the related position corresponding to a ridge (obstruction) located in front of the vehicle body W. 
     For example, the information presentation image is an image that alerts the driver to the state of the vehicle body W. In this case, the related position is a position in the first composite image which position corresponds to the position of the vehicle body W or the vicinity thereof. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the type of operation state to be displayed from the storage unit  232  on the basis of the operation state data input from the vehicle body control device  42 , and compositing the information presentation image at the related position in the first composite image that corresponds to the position of the vehicle body W (or the vicinity thereof) and that is suited to the type of the operation state to be displayed. In the example of the second composite image  290  illustrated in  FIG. 9 , an information presentation image  291   s  expressed as diagonal hatching and indicating that the grain tank  72  is full is shown in a related position corresponding to the grain tank  72  of the vehicle body W. 
     For example, the information presentation image is an image showing the state of a subregion, which is a partial region of the field. In this case, the related position is a position in the first composite image which position corresponds to the position of the subregion or the vicinity thereof. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the type of the state to be displayed (already-mowed/unmowed, whether or not the crop has fallen, the growth state of the crop, and the like) from the storage unit  232  on the basis of the field data input from the field analyzing unit  235 , and compositing the information presentation image at the related position in the first composite image which position corresponds to the position of the subregion or the vicinity thereof indicated by the field data. In the example of the second composite image  290  illustrated in  FIG. 41 , information presentation images  291   k , 91   m  expressed as right-downward diagonal hatching are shown in related positions corresponding to two rectangular subregions in the unmowed area G to the left of the vehicle body W. The information presentation image  291   k  shows that the crop has fallen in that subregion. The information presentation image  291   m  shows that there is a crop with poor growth in that subregion. In other words, the information presentation images  291   k , 91   m  are images showing the state of an unharvested crop in the subregion. 
     For example, the information presentation image is an image showing a state of the grain (the harvested crop). In this case, the related position is a position in the first composite image which position corresponding to the position where the grain was harvested or the vicinity thereof. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the type of the state to be displayed (yield, quality, or the like) from the storage unit  232  on the basis of the harvested crop data input from the vehicle body control device  42 , and compositing the information presentation image at the related position in the first composite image which position corresponds to the position where the grain was harvested or the vicinity thereof indicated by the harvested crop data. In the example of the second composite image  290  illustrated in  FIG. 41 , information presentation images  291   a ,  91   b ,  91   c ,  91   d ,  91   e ,  91   f ,  91   g ,  91   h ,  91   i , and  91   j  expressed as right-upward diagonal hatching are shown in related positions corresponding to rectangular subregions in the already-mowed area H to the right of the vehicle body W. The density of the hatching in each information presentation image indicates the magnitude of the yield in that subregion, and the higher the yield in that subregion, the greater the density of the hatching. In other words, these information presentation images are images showing the grain yield. Note that the information presentation image may be an image showing the quality of the grain, and the second compositing unit  236  may composite the information presentation image with the first composite image such that the density of the hatching increases as the quality (e.g., the protein content) in the subregion increases. 
     For example, the information presentation image is an image showing the target path of the vehicle body W. In this case, the related position is a position in the first composite image that is forward on the target path. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the target path to be displayed from the storage unit  232  on the basis of the operation state data input from the vehicle body control device  42 , and compositing the information presentation image at a position in the first composite image forward on the target path of the vehicle body W. In the example of the second composite image  290  illustrated in  FIG. 42 , the target path is a U-turn made before a ridge, and an information presentation image  291   r  which is a U-shaped arrow indicating the target path is shown in front and to the left of the vehicle body W, which is a position forward on the target path. 
     For example, the information presentation image is an image indicating that an event has occurred during harvesting operations. In this case, the related position is a position in the first composite image which position corresponds to the position where the event occurred or the vicinity thereof. The second compositing unit  236  generates the second composite image by reading out the information presentation image in accordance with the event to be displayed from the storage unit  232  on the basis of the operation state data input from the vehicle body control device  42 , and compositing the information presentation image at a related position in the first composite image which position corresponds to the position where the event occurred as indicated by the operation state data. In the example of the second composite image  290  illustrated in  FIG. 43 , an information presentation image  291   t  which reads “STOP” in a triangle is shown in front of the vehicle body W. The information presentation image  291   t  indicates that operations have stopped due to the grain tank  72  being full. 
     All the information presentation images may be composited with a single first composite image, or one or a plurality of the information presentation images may be composited. The type of information presentation image to be composited with the first composite image by the second compositing unit  236  may be determined, for example, on the basis of an operation made by the driver and accepted by an operation unit (not shown) provided on the display unit  40 , or may be automatically changed as time passes. 
     Example of Second Composite Image 
     Assume that the head-feeding combine is performing harvesting operations while traveling forward in a field. An example of the second composite image generated by the second compositing unit  236  at this time is illustrated in  FIG. 41 ,  FIG. 42 , and  FIG. 43  as the second composite image  290 . 
     The operation state of the vehicle body W at this time is that the vehicle body 
     W is traveling straight forward, the mowing unit  63  is in the working position and is operating, and the discharge device  73  is in the retracted position and is stopped. The vehicle body control device  42  outputs, to the image processing device  230 , operation state data indicating the stated operation state of the vehicle body W. 
     Assume that the viewpoint manipulation unit  41  has accepted an operation specifying a planar viewpoint. The viewpoint manipulation unit  41  outputs operation data indicating the planar viewpoint to the viewpoint determining unit  231 . On the basis of accepting the input of the operation data, the viewpoint determining unit  231  of the image processing device  230  determines the viewpoint of the first composite image composited by the first compositing unit  233  (the composite viewpoint) as the planar viewpoint, and outputs viewpoint data to that effect to the first compositing unit  233 . 
     The first compositing unit  233  generates the preliminary composite image by performing image processing including viewpoint conversion to the planar viewpoint and compositing in the shot images input from the four cameras. The first compositing unit  233  generates the vehicle body image by referring to the operation state data input from the vehicle body control device  42  and the viewpoint data input from the viewpoint determining unit  231 . Specifically, the vehicle body image showing the vehicle body W from the planar viewpoint is generated using the data expressing the external shapes of the mowing unit  63  in the working position and the transport unit  70 , the data expressing the external shape of the discharge device  73  in the retracted position, and the vehicle body data pertaining to remaining parts of the vehicle body W. The first compositing unit  233  generates the first composite image by compositing the vehicle body image with the preliminary composite image, and outputs the first composite image to the second compositing unit  236 . 
     Then, the second compositing unit  236  generates the second composite image by compositing the information presentation image indicating the information related to harvesting operations with the related position, which is a position in the first composite image related to that information presentation image, on the basis of the obstruction data output from the obstruction recognizing unit  234 , the field data output from the field analyzing unit  235 , and the operation state data and harvested crop data output from the vehicle body control device  42 , and outputs the second composite image to the display unit  40 . 
     Examples of the second composite image  290  generated by the second compositing unit  236  are illustrated in  FIG. 41 ,  FIG. 42 , and  FIG. 43 . A region  290   a  outside a boundary line E in the second composite image  290  is an image originating from the preliminary composite image, and is an image originating from the shot images shot by the four cameras. The already-mowed area H to the right and to the rear of the vehicle body W, and the unmowed area G to the left and to the front of the vehicle body W, are shown in the region  290   a . A region  290   b  inside the boundary line E in the second composite image  290  is a region originating from the vehicle body image. The vehicle body W is shown in the region  290   b.    
     In the example of  FIG. 41 , the information presentation images  291   a ,  91   b ,  91   c ,  91   d ,  91   e ,  91   f ,  91   g ,  91   h ,  91   i , and  91   j , which indicate the quality of the grain harvested in the corresponding subregions, are shown in the related positions in the region  290   a  corresponding to those subregions in the already-mowed area H. The density of the hatching in each information presentation image indicates the magnitude of the yield in that subregion, and the higher the yield in that subregion, the greater the density of the hatching. 
     Additionally, in the example of  FIG. 41 , the information presentation images  291   k  and  91   m , which indicate the state of the crops in the corresponding subregions, are shown in the related positions in the region  290   a  corresponding to those subregions in the unmowed area G. The information presentation image  291   k , which has relatively large gaps between the hatch lines, shows that the crop has fallen in that subregion. The information presentation image  291   m , which has relatively small gaps between the hatch lines, shows that the crop has experienced poor growth in that subregion. 
     In the example of  FIG. 42 , the information presentation images  291   n ,  91   p , and  91   q , which alert the driver to the presence of an obstruction, are shown in the related positions in the second composite image  290  corresponding to positions in the vicinity of obstructions (people, ridges). Specifically, a circular information presentation image  291   n  and the information presentation image  291   p  in the shape of an exclamation point are shown at a position corresponding to the vicinity of a person (around and to the front of the person). The information presentation image  291   q  expressed as diagonal hatching is shown in a position corresponding to the ridge. 
     Additionally, in the example of  FIG. 42 , the information presentation image  291   r , which is a U-shaped arrow indicating the target path, is shown in the second composite image  290 , in a position forward on the target path of the vehicle body W. 
     In the example of  FIG. 43 , the information presentation image  291   s , which alerts the driver to the state of the vehicle body W, is shown in a related position in the region  290   a  corresponding to the position of the vehicle body W. Specifically, the information presentation image  291   s  expressed as diagonal hatching and indicating that the grain tank  72  is full is shown in a position in the region  290   a  corresponding to the grain tank  72  of the vehicle body W. 
     Additionally, in the example of  FIG. 43 , the information presentation image  291   t , which indicates that an event has occurred during harvesting operations, is shown in a related position in the region  290   a  corresponding to the position where the event occurred. Specifically, the information presentation image  291   t , which indicates that operations have stopped due to the grain tank  72  being full, is shown in a related position in the region  290   a  corresponding to the position in the field where the grain tank  72  became full. 
     Variations on Sixth Embodiment 
     (1)  FIG. 44  illustrates another form of the image processing device  230 . In the following descriptions, configurations that are the same as those in the foregoing embodiment may be given the same reference signs, and may not be described in detail. 
     The image processing device  230  according to the present embodiment includes a third compositing unit  237  in addition to the viewpoint determining unit  231 , the storage unit  232 , the first compositing unit  233 , the obstruction recognizing unit  234 , and the field analyzing unit  235 . The third compositing unit  237  generates a third composite image by compositing the second composite image generated by the second compositing unit  236  with a map image. The third compositing unit  237  then outputs the third composite image to the display unit  40 . In other words, the third compositing unit  237  is a display control unit that causes the third composite image to be displayed in the display unit  40 . The map image is an image expressing a map showing points in the field corresponding to the related positions. In other words, the map image is an image that indicates, as a map, locations, in the field, of the information presentation images shown in the second composite image, corresponding to the information expressed by those information presentation images. 
     For example, when an information presentation image indicating that an event has occurred is shown in the second composite image, the third compositing unit  237  specifies a point in the field where the event has occurred on the basis of the operation state data input from the vehicle body control device  42 . The third compositing unit  237  generates the map image indicating that point, generates the third composite image by compositing the map image with the second composite image, and outputs the third composite image to the display unit  40 . 
     An examples of a third composite image  292  generated by the third compositing unit  237  is illustrated in  FIG. 45 . This third composite image  292  is generated compositing a map image  293  with the right side of the second composite image illustrated in  FIG. 43 . Position presentation images  294   a  and  94   b  near a boundary between the already-mowed area H and the unmowed area G, as well as a position presentation image  294   c  in the already-mowed area H, are indicated in the map image  293 . The position presentation image  294   a  shows the point where the vehicle body W is located in the field. The position presentation image  294   b  and the position presentation image  294   c  show points in the field where operations have stopped (the event) due to the grain tank  72  being full. 
     Although the present embodiment has described an example where the point where the event occurred is shown in the map image generated by the third compositing unit  237 , other points related to the information presentation image may be shown in the map image. For example, points where obstructions (people, ridges, or the like) are present, points in the field where an abnormal condition has occurred in the crop (falling over, poor growth, or the like) may be indicated in the map image by a location presentation image. 
     The image processing device  230  may be configured to be capable of outputting the second composite image and the third composite image to the display unit  40  selectively. In other words, the image processing device  230  may be configured so that the second compositing unit  236  serving as a display control unit outputs the second composite image to the display unit  40 , and the third compositing unit  237  serving as a display control unit outputs the third composite image to the display unit  40 . 
     (2) The foregoing embodiment described an example in which the vehicle body W of the head-feeding combine is provided with four cameras. The number of cameras is not limited thereto, however, and one, two, three, or five or more cameras may be provided in the vehicle body W. 
     (3) Although the foregoing embodiment describes an example in which the vehicle body image showing the vehicle body W is shown in the second composite image, part of the vehicle body W that has been shot may be shown in the second composite image. 
     (4) The foregoing embodiment described an example in which the second composite image is displayed in the display unit  40  and the third composite image is displayed in the display unit  40 . The first composite image and the second composite image may be displayed in the display unit  40  in an alternating manner, or the image displayed in the display unit  40  may be switched between the first composite image and the second composite image on the basis of operations made by the driver. The first composite image, the second composite image, and the third composite image may be displayed in the display unit  40  in an alternating manner, or the image displayed in the display unit  40  may be switched between the first composite image, the second composite image, and the third composite image on the basis of operations made by the driver. 
     (5) The foregoing embodiment described an example in which the subregions, as well as the information presentation images displayed corresponding to the subregions, are rectangular. However, the subregions and the information presentation images may have any shape and size, and are not limited to the above-described examples. 
     INDUSTRIAL APPLICABILITY 
     The present invention can be applied in harvesters that harvest planted crops while traveling, and can be applied in standard combines, head-feeding combines, and the like. The present invention can also be applied in work machines that work in fields, such as rice transplanters, management machines, tractors, and the like. 
     DESCRIPTION OF REFERENCE SIGNS 
       2 : Crawler traveling device (traveling device) 
       3 : Mowing unit (harvesting unit) 
       3   a : Mowing frame (frame) 
       6 : Raking auger (auger) 
       7 : Divider 
       8 : Driving section 
       8   a : Driver&#39;s seat 
       9   a : Roof part 
       9   e : Side glass 
       9   f : Projecting part 
       10 : Feeder (transport unit) 
       11 : Threshing device 
       11   a : Main body part 
       11   b : Top panel 
       12 : Grain tank 
       13 : Discharge device 
       14 : Rear cover part 
       15 : Engine 
       16 : Radiator 
       17 : Dust-resistant case (dust-resistant unit) 
       21 : Front camera 
       22 : Rear camera 
       23 : Right camera (first side camera) 
       24 : Left camera (second side camera) 
       25 : Lower-right camera (camera) 
       26 : Lower-left camera (camera) 
       27 : Lower-rear camera (camera) 
       32 : Storage unit 
       33 : Image compositing unit 
       40 : Display unit 
       50 : Composite image 
       62 : Crawler traveling device (traveling device) 
       63 : Mowing unit (harvesting unit) 
       63   a : Divider 
       63   b : Lifting device 
       68 : Driving section 
       68   a : Driver&#39;s seat 
       69   a : Roof part 
       69   e : Side glass 
       69   f : Projecting part 
       70 : Transport unit 
       70   c : Feed chain 
       70   d : Rail stand 
       71 : Threshing device 
       71   f : Front wall 
       71   c : Waste straw processing device 
       72 : Grain tank 
       75 : Engine 
       76 : Radiator 
       77 : Dust-resistant case (dust-resistant unit) 
       78 : Satellite positioning module 
       81 : Front camera 
       82 : Rear camera 
       83 : Right camera (first side camera) 
       84 : Left camera (second side camera) 
       86 : Lower-left camera (camera) 
       90 : Composite image 
       150 : Composite image 
       190 : Composite image 
       232 : Storage unit 
       233 : First compositing unit 
       236 : Second compositing unit (display control unit) 
       237 : Third compositing unit (display control unit) 
       290 : Second composite image 
       291   a - 91   t : Information presentation image 
       292 : Third composite image 
       293 : Map image 
     A: Receiving part 
     V: Vehicle body 
     W: Vehicle body