Image processing device and image processing method

An image processing device according to an aspect of the embodiment includes a display controller and a determining unit. The display controller generates a synthesized image when viewing a perimeter of a vehicle from a virtual viewpoint based on an image from an image capturing device and causes a display unit to display the synthesized image. The determining unit determines, in a case where a screen other than a virtual viewpoint screen including the synthesized image is displayed on the display unit, whether a switching condition to a notification screen for notifying an occupant of presence of an obstacle is satisfied when the obstacle is detected by a detector. The display controller causes the display unit to display the notification screen obtained by superimposing a predetermined notification image on the virtual viewpoint screen, when the determining unit determines that the switching condition is satisfied.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-103861, filed on May 21, 2015, the entire contents of which are incorporated herein by reference.

FIELD

The embodiment discussed herein is directed to an image processing device and an image processing method.

BACKGROUND

There is known a conventional apparatus that detects an obstacle located at a blind spot of a driver by using an obstacle sensor mounted on a vehicle and notifies a driver of the detected obstacle. When detecting an obstacle, the apparatus notifies the driver of the obstacle by performing display switching (see Japanese Laid-open Patent Publication No. 2013-190957, for example).

However, when display switching is performed every time an obstacle is detected like the conventional apparatus, the apparatus notifies a driver of an obstacle even when it is not required that the driver is notified of the obstacle. As described above, the conventional apparatus cannot appropriately notify a driver of an obstacle in some cases.

SUMMARY

An image processing device according to an aspect of the embodiment includes a display controller and a determining unit. The display controller generates a synthesized image when viewing a perimeter of a vehicle from a virtual viewpoint based on an image from an image capturing device and causes a display unit to display the synthesized image. The determining unit determines, in a case where a screen other than a virtual viewpoint screen including the synthesized image is displayed on the display unit, whether a switching condition to a notification screen for notifying an occupant of presence of an obstacle is satisfied when the obstacle is detected by a detector that detects the obstacle around the vehicle. The display controller causes the display unit to display the notification screen obtained by superimposing a predetermined notification image on the virtual viewpoint screen, when the determining unit determines that the switching condition is satisfied.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of an image processing device and an image processing method of the present disclosure will be in detail explained with reference to the accompanying drawings. In addition, the embodiment disclosed below is not intended to limit the present invention.

1. Image Processing Method

FIGS. 1A to 1Care explanatory diagrams illustrating an image processing method according to an embodiment. The image processing method is performed by an image processing device10mounted on a vehicle C, for example.FIG. 1Ais a schematic diagram illustrating a positional relationship between the vehicle C and an obstacle.FIGS. 1B and 1Care diagrams illustrating examples of a screen that is displayed on a display unit.

In the image processing method according to the embodiment, a driver is notified of an obstacle by displaying the obstacle detected by detectors40ato40dmounted on the vehicle G on a display unit (not illustrated). Herein, although it is explained that the person H is detected as an obstacle, the obstacle is not limited to the person H. For example, an obstacle may be other vehicles such as a bicycle and a motorbike, or may be an electric pole or a tree.

The image processing device10generates a synthesized image for the case of viewing the perimeter of the vehicle from a virtual viewpoint, on the basis of a captured image input from an image capturing device (not illustrated) mounted on the vehicle C. The image processing device10causes the display unit (not illustrated) to display the generated synthesized image. As described above, the display unit displays a virtual viewpoint screen that includes the synthesized image.

As illustrated in upper parts ofFIGS. 1B and 1C, for example, the display unit displays an image100(hereinafter, navigation image) that includes a navigational map generated by a navigation device. As described above, the display unit displays a navigation screen101that includes the navigation linage100.

Hereinafter, in a case where the navigation screen101is, for example, displayed on the display unit as a screen other than a virtual viewpoint screen that includes a synthesized image, it will be explained about an image processing method performed by the image processing device10when the person H of an obstacle approaches the vehicle.

The detectors40ato40ddetecting an obstacle around the vehicle C are mounted on the vehicle C. The detectors40ato40dare clearance sonars, for example. The detectors40ato40dhave predetermined detection ranges R1to R4to detect an object located in the detection ranges R1to R4as an obstacle. InFIG. 1A, the detector40adetects the person H located in the predetermined detection range R1as an obstacle.

In a case where the navigation screen101is displayed on the display unit, the image processing device10determines whether a switching condition to a notification screen200is satisfied when the person H is detected by the detector40a. The notification screen200is a screen for notifying the driver of the presence of the person H that is an obstacle.

For example, in a case where the navigation screen101is displayed on the display unit as illustrated in upper parts ofFIGS. 1B and 1C, changing the display of the display unit to the notification screen200by the image processing device10results in obstructing an operation of the driver when the driver is operating the navigation device. Therefore, the image processing device10employs, for example, the presence or absence of an operation for the navigation device as a switching condition. When an operation is not performed on the navigation device, the image processing device10switches from the navigation screen to the notification screen200. On the other hand, when an operation is performed on the navigation device, the image processing device10does not switch from the navigation screen to the notification screen.

When it is determined that the switching condition is satisfied, namely, an operation is not performed on the navigation device, the image processing device10causes the display unit to display the notification screen200. As illustrated in the lower part ofFIG. 1B, for example, the notification screen200is a screen that includes a synthesized image300and a captured image500. The synthesized image300is obtained by superimposing a predetermined notification image41on a virtual viewpoint image.

On the other hand, when it is determined that the switching condition is not satisfied, namely, an operation is performed on the navigation device, the image processing device10does not notify the driver of an obstacle even when the detector40adetects the person H as the obstacle. Therefore, as illustrated in the lower part ofFIG. 1C, the navigation screen101including the navigation image100is continuously displayed on the display unit.

As described above, in a case where a screen other than a virtual viewpoint screen is displayed on the display unit, the image processing device10changes the display of the display unit to the notification screen200when the switching condition to the notification screen200is satisfied. As a result, the image pro-ceasing device10can appropriately notify a driver of an obstacle in the case of requiring a notification. It should be noted that employing the presence or absence of an operation for a navigation device as described above as a switching condition is only an example. The image processing device10can determine whether switching to the notification screen200is performed on the basis of a condition other than the switching condition. Hereinafter, it will be further explained about a perimeter monitoring system1that includes the image processing device10.

2. Perimeter Monitoring System

FIG. 2is a diagram illustrating a configuration example of the perimeter monitoring system1according to the embodiment. As illustrated inFIG. 2, the perimeter monitoring system1includes the image processing device10, an image capturing device20, a navigation device30, a detector40, and a sensor assembly50.

2.1 Image Capturing Device

As illustrated inFIG. 3, the image capturing device20includes a front image capturing unit20athat is placed in the front of the vehicle C, a rear image capturing unit20bthat is placed in the rear of the vehicle C, a right-image capturing unit20cthat is placed in the right side of the vehicle C, and a left image capturing unit20dthat is placed in the left side of the vehicle C.FIG. 3is a diagram illustrating an arrangement example of the image capturing units20ato20d.

The image capturing units20ato20dinclude image capturing elements such as a Charge Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS), and outputs images (hereinafter, captured images) around the vehicle C captured by the image capturing elements to the image processing device10. Moreover, the image capturing units20ato20dcapture respective images whose imaging directions are front, rear, right, and left directions of the vehicle C.

The image capturing units20ato20demploy wide angle lenses such as fisheye lenses. Each of the image capturing units20ato20dhas an angle of view of which the size is not less than 180 degrees. By using the image capturing units20ato20d, the entire perimeter of the vehicle C can be captured.

2.2 Navigation Device

The navigation device30illustrated inFIG. 2includes a display unit31, a voice output unit32, an input operating unit33, and a controller34. The navigation device30has a navigation function and an audio function when a driver of the vehicle C is driving. Moreover, the navigation device30outputs, to the image processing device10, information on a screen displayed on the display unit31and information on an input operation received by the input operating unit33.

The display unit31includes a Liquid Crystal Display (LCD). The display unit31displays, for example, the navigation image100(seeFIG. 1) and an image (hereinafter, television image) based on television broadcasting signals in accordance with an instruction of the controller34. Moreover, the display unit31displays a captured image, a virtual viewpoint image, or a synthesized image, as described later.

The voice output unit32includes a speaker. The voice output unit32outputs, for example, voice guidance for the navigation function and voices based on television broadcasting signals in accordance with an instruction of the controller34. Moreover, the input operating unit33receives an input operation that is performed by an operator with respect to the navigation device30. Moreover, when the display unit31is for example a touch-screen display, the display unit31may have a function of the input operating unit33.

The controller34controls the units included in the navigation device30. The controller34causes the display unit31to display a predetermined image or causes the voice output unit32to output audio data, on the basis of an input operation received by the input operating unit33, for example.

As illustrated inFIG. 3, the detector40includes the right front detector40aplaced in the right front of the vehicle C, the left front detector40bplaced in the left front of the vehicle C, the right rear detector40cplaced in the right rear of the vehicle C, and the left rear detector40aplaced in the left rear of the vehicle C.

The detectors40ato40dare clearance sonars. The detectors40ato40ddetect objects located in the detection ranges R1to R4of the respective clearance sonars as obstacles. Each of the detectors40ato40dnotifies the image processing device10of the detected obstacle. It should be noted that the detectors40ato40dare not limited to ultrasonic sensors such as for example clearance sonars. The detectors40ato40dmay be radio-wave sensors such as for example millimeter wave radars.

The arrangement of the detector40is not limited to the example illustrated inFIG. 3. Like a back sonar for example, the detector40may be provided in the rear of the vehicle C. Furthermore, the number of the detectors40ato40dmay foe four or more.

2.4 Sensor Assembly

The sensor assembly50includes various types of sensors, such as a shift sensor51and a speed sensor52, which detect the state of the vehicle C. The shift sensor51detects the position of a shift lever (not illustrated). The position of the shift lever includes “parking” in which the vehicle C is perfectly stopped and “reverse” in which the vehicle C moves backward. The speed sensor52detects a traveling speed (hereinafter, vehicle speed) of the vehicle C. The sensor assembly50outputs the detection result of each sensor to the image processing device10.

2.5 Image Processing Device

The image processing device10includes an image controller11(equivalent to example of “display controller”), a determining unit12, and a storage unit13.

2.5.1 Image Controller

The image controller11performs various kinds of image processing with respect to image data acquired from the image capturing device20, and generates a captured image, a virtual viewpoint image, or a synthesized image to be displayed on the display unit31.

The image controller11acquires captured image data from the image capturing units20ato20d. The image controller11selects one or more images from among the captured images of the image capturing units20ato20d,depending on the type of an image to be displayed on the display unit31. The image controller11selects one or more captured, images in accordance with the notification of the determining unit12.

The image controller11performs a coordinate transformation process with respect to the plurality of captured image, and generates a virtual viewpoint image that is an image viewed from a virtual viewpoint. As the coordinate transformation process, the image controller11projects (maps), for example, the captured images on a predetermined projection plane, and sets, as the virtual viewpoint image, an image in a predetermined viewing angle area when being viewed from the virtual viewpoint, among the captured images projected on the predetermined projection plane.

For example, the image controller11stores a table that indicates a correspondence relationship between the position of data included in the captured images of the image capturing units20ato20dand the position of the predetermined projection plane. By using the table, the image controller11projects the data included in the captured images of the image capturing units20ato20don the corresponding position of the predetermined projection plane.

The predetermined projection plane has, for example, a substantially hemispherical shape (for example, bowl shape). The central area (for example, bottom of bowl) of the hemispherical shape is the position of the vehicle C, and the outside (outer circumferential area of substantially hemispherical shape, for example) of the position of the vehicle C is equivalent to an area around the vehicle C. It should be noted that the predetermined projection plane is not limited to a curved surface. It may be a flat surface, for example.

The image controller11generates a synthesized image obtained by superimposing a predetermined notification image on a virtual viewpoint image. For example, the predetermined notification image is an image corresponding to any of the detection ranges R1to R4of the detector40. The image controller11generates a synthesized image by superimposing a notification image on the virtual viewpoint image, in which the notification image is an image that indicates a detection range (R1to R4) in a direction (front or rear direction) in which the detector40detects an obstacle.

FIG. 4is a diagram illustrating an example of a notification screen200that is generated from the image controller11. As illustrated inFIG. 4, when the detector40detects the person H located in front of the vehicle C as an obstacle, the image controller11generates, as the notification screen200, the synthesized image300obtained by superimposing images41a,41b(notification images) corresponding to the detection ranges R1, R2of the detectors40a,40bprovided, in the front of the vehicle C on a virtual viewpoint image600.

The images41a,41bon the virtual viewpoint image600are not necessarily identical with the actual detection ranges R1, R2. It is sufficient that the synthesized image300is an image that indicates where the obstacle exists around the vehicle C. For example, because the notification image may be an arrow, it may not be the images41a,41bcorresponding to the detection ranges R1, R2.

The notification screen200generated from the image controller11is not limited to the example illustrated inFIG. 4. For example, as illustrated inFIG. 5, the detected obstacle may be displayed after highlighting is performed by surrounding the obstacle with a frame. In this case, the image controller11may generate the notification screen200by apposing the synthesized image300obtained by superimposing the notification images41a,41bon the virtual viewpoint image and the front captured image500in which highlighting is performed on the obstacle.

The positions at which the notification images41a,41bare superimposed on the virtual viewpoint image600are not limited to the example illustrated inFIGS. 4 and 5. For example, the image controller11may superimpose a notification image on a vehicle image included in the synthesized image300.

As described above, the image controller11generates the synthesized image300and the captured image500or the virtual viewpoint image600in accordance with the notification of the determining unit12, and causes the display unit31to display the image(s).

2.5.2 Determining Unit

In a case where a screen other than the virtual viewpoint screen including the synthesized image300is displayed on the display unit31, the determining unit12determines whether a switching condition to the presence of an obstacle is satisfied when the obstacle is detected by the detector40. When it is determined that the switching condition is satisfied, the determining unit12notifies the image controller11of the effect that the detection result by the detector40and the notification screen200are displayed.

2.5.2.1 Example of Switching Condition

The determining unit12determines whether each of display conditions is satisfied, for example. When all the display conditions are satisfied, the determining unit12determines that the switching condition is satisfied. The display conditions will be explained by usingFIG. 6.FIG. 6is a diagram illustrating a display condition table that indicates the satisfaction or unsatisfaction of each display condition.

As described above, a display condition determined by the determining unit12includes, as an example, the presence or absence of an input operation with respect to the navigation device30. For example, when an input operation with respect to the navigation device30is not performed until a predetermined time passes after the detector40detects an obstacle, the determining unit12determines that there is not the input operation.

In other words, the determining unit12determines that the condition of “input operation OFF” is satisfied, and sets “input operation OFF” of the display condition table to “1”. On the other hand, when the input operation with respect to the navigation device30is performed until the predetermined time passes after the detector40detects the obstacle, for example, the determining unit12determines that there is the input operation, and sets “input operation OFF” of the display condition table to “0”.

Herein, the presence or absence of an input operation with respect to the navigation device30is determined in a predetermined time after detecting an obstacle. For example, the presence or absence of the input operation may, however, be determined in a predetermined time before detecting an obstacle. In other words, when an input operation with respect to the navigation device30is not performed within a predetermined time until before the detector40detects an obstacle, for example, the determining unit12determines that there is not the input operation.

As an example of the display condition, the determining unit12determines whether the display unit31is displaying a television screen that includes television images. When the television screen is not displayed on the display unit31, for example, the determining unit12determines that the display condition is satisfied, and sets “television screen OFF” of the display condition table to “1”. On the other hand, when the television screen is displayed on the display unit31, for example, the determining unit12determines that the display condition is not satisfied, and sets “television screen OFF” of the display condition table to “0”.

As described above, when the television screen is displayed on the display unit31, it is considered that the driver is watching the television screen and the vehicle C is not driven. In this case, the determining unit12determines that the driver may not foe notified of the obstacle and thus the switching to the notification screen200is not performed. As a result, the driver can watch television without being obstructed by the notification screen200. Moreover, when the television screen is not displayed on the display unit, the determining unit12can appropriately notify the driver of an obstacle by determining that the switching to the notification screen200is performed.

The determining unit12determines whether the display condition is satisfied in accordance with the position of the shift lever, for example. Specifically, when the shift lever is located at a position other than parking and reverse, for example, the determining unit12determines that the display condition is satisfied, and sets “other than shift lever P, R” of the display condition table to “1”. On the other hand, when the shift lever is located at the position of parking or reverse, for example, the determining unit12determines that the display condition is not satisfied, and sets “other than shift lever P, R” of the display condition table to “0”.

When the shift lever is located at the position of “P”, namely, the position of parking, the vehicle C is stopping. In this case, because the vehicle C does not collide against an obstacle, the determining unit12determines that the switching to the notification screen200is not performed. Therefore, when the vehicle C may collide against the detected obstacle, the determining unit12can appropriately notify the driver of the obstacle by determining that the switching to the notification screen200is performed.

When the shift lever is located at “R”, namely, the position of reverse, it is considered that the vehicle C is moving backward and thus the driver sufficiently pays attention to the perimeter of the vehicle G. Alternatively, the virtual viewpoint screen is displayed on the display unit31, and the driver is already notified of the obstacle. Therefore, in this case, the determining unit12determines that the switching to the notification screen200is not performed. As described above, when the driver does not sufficiently pay attention to the perimeter of the vehicle C, or when the driver is not notified of the obstacle, the determining unit12can appropriately notify the driver of the obstacle by determining that the switching to the notification screen200is performed.

The determining unit12determines whether the display condition is satisfied in accordance with the vehicle speed of the vehicle C, for example. Specifically, when the speed of the vehicle C is not less than a first speed Vth1that is faster than 0 km/h and is not more than a second speed Vth2that is faster than the first speed Vth1, for example, the determining unit12determines that the display condition is satisfied, and sets “vehicle speed within predetermined range” of the display condition table to “1”. On the other hand, when the vehicle speed is smaller than the first speed Vth1or is larger than the second speed Vth2, the determining unit12determines that the display condition is riot satisfied, and sets “vehicle speed within predetermined range” of the display condition table to “0”

For example, when the vehicle speed is smaller than the first speed Vth1, the vehicle C is substantially stopping, and thus a collision possibility against an obstacle is small. Moreover, when the vehicle speed is larger than the second speed Vth2, the driver concentrates on the drive of the vehicle. In this case, if the switching to the notification screen200is performed, it is concerned that the drive of the driver is obstructed. Therefore, the determining unit12determines that the switching to the notification screen200is not performed when the vehicle speed is out of the predetermined range. As described above, the determining unit12can appropriately notify the driver of an obstacle by determining that the switching to the notification screen200is performed when the vehicle speed is within the predetermined range.

When all the display conditions described above are satisfied, for example, namely, all the display conditions of the display condition table are set to “1”, the determining unit12determines that the switching condition is satisfied. On the other hand, because the condition of “other than shift lever P, R” is “0” in the example illustrated inFIG. 6, it is not determined that all the display conditions are satisfied. The determining unit12determines that the switching condition is not satisfied.

Herein, although four display conditions are illustrated, display conditions are not limited to four. For example, when the navigation device30is performing voice guidance, the determining unit12may determine that the switching to the notification screen200is not performed because it is concerned that the guidance of the navigation device30is obstructed. The number of display conditions may be four or more or four or less. Moreover, the driver may select a condition in which the switching to the notification screen200is performed.

2.5.2.2 Example of Termination Condition

The determining unit12determines whether each of display stop conditions is satisfied, for example. When all the display step conditions a re satisfied, the determining unit12determines that a termination condition is satisfied, and instructs the image controller11to terminate the display of the notification screen200.

By usingFIGS. 7 to 9, the display stop conditions will be explained.FIG. 7is a diagram illustrating a display stop condition table that indicates the satisfaction or unsatisfaction of each display stop condition.FIG. 8is a diagram illustrating a stop OR condition table that indicates the satisfaction or unsatisfaction of a slop OR condition of the display stop conditions.FIG. 9is a diagram explaining the stop OR condition.

As one of the display stop conditions, the determining unit12determines whether the display unit31is displaying the notification screen200that indicates the detection result of the detector40. When the display unit31is displaying the notification screen200, the determining unit12determines that the display stop condition of “notification screen display” is satisfied, and sets “notification screen display” of the display stop condition table illustrated inFIG. 7to “1”. On the other hand, when the display unit31is not displaying the notification screen200, the determining unit12determines that the display stop condition of “notification screen display” is not satisfied, and sets “notification screen display” of the display stop condition table to “0”.

The determining unit12determines whether the display stop condition is satisfied in accordance with the position of the shire lever. Specifically, when the position of the shift lever is a position other than parking and reverse, for example, the determining unit12determines that the display stop condition is satisfied, and sets “other than shift lever P, R” of the display stop condition table to “1”. On the other hand, when the shift lever is located at the position of parking or reverse, for example, the determining unit12determines that the display stop condition is not satisfied, and sets “other than shift lever P, R” of the display condition table to

The determining unit12determines whether an OR condition as the display stop condition is satisfied. When at least one of stop OR conditions is satisfied, the determining unit12determines that the OR condition is satisfied.

As an example of the display stop condition, the determining unit12determines whether a switch of the detector40is OFF. When the switch of the detector40is OFF, the determining unit12determines that the switch of the detector40is OFF, and sets “detector switch OFF” of the stop OR condition table illustrated inFIG. 8to “1”.

On the other hand, when the switch of the detector40is ON, the determining unit12determines that the switch of the detector40is not OFF, and sets “detector switch OFF” of the stop OR condition table to “0”.

The switch of the detector40can be switched by the driver between ON and OFF, for example. Therefore, when the switch of the detector40is switched by the driver to OFF, for example, the determining unit12determines that the detection of an obstacle is unnecessary and thus the display of the notification screen200is terminated.

As an example of the display stop condition, the determining unit12determines whether a time in which an obstacle is not detected by the detector40exceeds a predetermined time P1. When the obstacle is not detected by the detector40for a predetermined time, the determining unit12determines that the predetermined time has passed after the obstacle is detected, and sets “No obstacle detection for predetermined time” of the stop OR condition table to “1”. On the other hand, when the obstacle is detected within the predetermined time, the determining unit12determines that the predetermined time has not passed after the obstacle is detected, and sets “No obstacle detection for predetermined time” of the stop OR condition table to “0”.

As described above, when an obstacle is not detected for a predetermined time, the determining unit12determines to terminate the display of the notification screen200because the obstacle does not exist around the vehicle C.

As an example of display stop condition the determining unit12determines whether a time in which the speed of the vehicle C is less than the first speed Vth1exceeds a predetermined time. When the time in which the vehicle speed is smaller than the first speed Vth1exceeds the predetermined time, the determining unit12sets “vehicle speed below first speed Vth1for predetermined time” of the stop OR condition table to “1”. On the other hand, when the time in which the vehicle speed is smaller than the first speed Vth1is not more than the predetermined time, the determining unit12sets “vehicle speed below first speed Vth1for predetermined time” of the stop OR condition table to “0”.

As an example of the display stop condition, the determining unit12determines whether the speed of the vehicle C exceeds a third speed Vth3faster than the second speed Vth2. When the vehicle speed exceeds the third speed Vth3, the determining unit12sets “vehicle speed larger than third speed Vth3” of the stop OR condition table to “1”. On the other hand, when the vehicle speed is smaller than the third speed Vth3, the determining unit12“vehicle speed larger than third speed Vth3” of the stop OR condition table to “0”.

By usingFIG. 9, it will be explained about the relationship between the vehicle speed and the determination by the determining unit12for the display condition and the display stop condition. InFIG. 9, the case, in which the determining unit12displays the notification screen200, namely, it is determined that the display condition is satisfied, is explained as “ON”, and the case, in which the determining unit12does not display the notification screen200, namely, it is determined that the display stop condition is satisfied, is explained as “OFF”.

InFIG. 9, the upper part illustrates a time change in the speed of the vehicle C, and the lower part illustrates the determination result of the determining unit12. As illustrated in the upper part ofFIG. 9, when the vehicle speed of the vehicle C is changed and the vehicle speed, is not less than the first speed Vth1, the determining unit12determines the state of the notification as “ON”, namely, determines to display the notification screen200. When the vehicle speed exceeds the third speed Vth3, the determining unit12determines the state of the notification as “OFF”, namely, determines not to display the notification screen200.

When the vehicle speed is not more than the second speed Vth2, the determining unit12determines the state of the notification as “ON”, namely, determines to display the notification screen200. When a time in which the vehicle speed is smaller than the first speed Vth1runs beyond the predetermined time P1, the determining unit12determines the state of the notification as “OFF”, namely, determines not to display the notification screen200.

As described above, a speed (second speed Vth2) at which it is determined that the notification screen200is displayed is different from a speed (third speed Vth3) at which it is determined that the display of the notification screen200is terminated. Therefore, when the vehicle speed is frequently changed like a time T1illustrated inFIG. 9, for example, the notification screen200cannot be prevented from being frequently switched between start and termination.

When a time in which the vehicle speed is less than the first speed Vth1is continued for the predetermined time P1, the display of the notification screen200is terminated. As a result, when the vehicle speed is frequently changed like a time T2illustrated inFIG. 9, for example, the notification screen200cannot be prevented from being frequently switched between start and termination.

When at least one of the stop OR conditions described above is satisfied, for example, namely, at least one of the stop OR conditions of the stop OR condition table inFIG. 8is “1”, the determining unit12determines that the OR condition is satisfied, and sets “OR condition satisfaction” of the display stop condition table as illustrated inFIG. 7to “1”.

When all the display stop conditions described above are satisfied, tor example, namely, all the display stop conditions of the display stop condition table are “1”, the determining unit11determines that the termination condition is satisfied. In the example illustrated inFIG. 7, because all the display stop conditions are “1”, the determining unit12determines that the termination condition is satisfied, and instructs the image controller11to terminate the notification screen200.

The case where three conditions are employed as the display stop condition and four conditions are employed as the stop OR condition has been explained. However, the display stop condition and the stop OR condition are not limited to the above case. For example, in a case where the notification screen200is displayed on the display unit31, when an input operation is performed with respect to the navigation device30, the determining unit12may assume that the driver has confirmed the notification screen200and determine to terminate the display of the notification screen200. The number of the display stop conditions and the stop OR conditions may be four or three or more, or may be four or three or less. Alternatively, the driver may select a condition for terminating the notification screen200.

The case where the determining unit12determines to terminate the display of the notification screen200when all the display step conditions illustrated inFIG. 7are satisfied has been explained. However, the present embodiment is not limited to the above. For example, when “other than shift lever P, R” ofFIG. 7is changed to “0”, namely, the shift lever is changed to parking or reverse, the determining unit12may determine to terminate the display of the notification screen200regardless of the satisfaction or unsatisfaction of the OR condition. Alternatively, when the predetermined time has passed after displaying the notification screen200, the determining unit12may determine to terminate the display of the notification screen200.

2.5.3 Storage Unit

The storage unit13stores, for example, the display condition table, the display stop condition table, and the stop OR condition table. Moreover, the storage unit13stores information required for the determination of whether the switching condition is satisfied and the determination of whether the termination condition is satisfied, which are performed by the determining unit12. The storage unit13is a semiconductor memory device such as a Random Access Memory (RAM) and a flash memory, or a storage device such as a hard disk and an optical disc.

3. Notification Processing

Next, notification processing performed by the image processing device10will be explained. The image processing device10executes the notification processing that includes notification start processing and notification termination processing.

3.1 Notification Start Processing

FIG. 10is a flowchart illustrating notification start processing that is performed by the image processing device10. First, the image processing device10determines whether the detector40detects an obstacle (Step S101). When it is determined that the detector40does not detect an obstacle (Step S101: No), the image processing device10returns the process to Step S101to wait for the detection of an obstacle.

On the other hand, when the detector40detects an obstacle (Step S101: Yes), the image processing device10determines whether a virtual viewpoint screen including the synthesized image300is displayed on the display unit31(Step S102). When the virtual viewpoint screen including the synthesized image300is displayed on the display unit31(Step S102: Yes), the image processing device10advances the process to Step S104.

When the virtual viewpoint screen including the synthesized image300is not displayed on the display unit31(Step S102: No), the image processing device10determines whether a switching condition is satisfied (Step S103). When the switching condition is not satisfied (Step S103: No), the image processing device10determines that the switching to the notification screen200is unnecessary, and terminates the notification start processing.

When the switching condition is satisfied (Step S103: Yes), the image processing device10generates the synthesized image300(Step S104), and causes the display unit31to display the notification screen200obtained by superimposing a notification image on the generated synthesized image300(Step S105).

At timing at which the display condition is changed, for example, the vehicle speed of the vehicle C is changed or the position of the shift lever is changed, the image processing device10previously updates the display condition table, and performs the determination on the satisfaction or unsatisfaction of the switching condition by referring to the display condition table in Step S103. Alternatively, the image processing device10may determine whether the switching condition is satisfied by determining all the display conditions at timing at which Step S103is executed.

The image processing device10may exchange Step S102for Step S103, or may simultaneously execute Steps S102and S103.

3.2 Notification Termination Processing

FIG. 11is a flowchart illustrating notification termination processing that is performed by the image processing device10. The image processing device10executes the notification termination processing after executing the notification start processing.

First, the image processing device10continues to display the notification screen200on the display unit31(Step S201). Next, the image processing device10determines whether a termination condition is satisfied (Step S202). When it is determined that the termination condition is not satisfied (Step S202: No), the image processing device10returns the process to Step S201, and continues to display the notification screen200on the display unit31.

On the other hand, when it is determined that the termination condition is satisfied (Step S202: Yes), the image processing device10instructs the display unit31to terminate the display of the notification screen200(Step S203). Upon receiving an instruction for terminating the display of the notification screen200from the image processing device10, the display unit31displays for example the screen just before displaying the notification screen200. Alternatively, the image processing device10may determine an image to be displayed on the display unit31.

At timing at which the display stop condition and the stop OR condition are changed, for example, the vehicle speed of the vehicle C is changed or the position of the shift lever is changed, the image processing device10previously updates the display stop condition table and the stop OR condition table, and performs the determination on the satisfaction or unsatisfaction of the termination condition by referring to the display stop condition table in Step S202. Alternatively, the image processing device10may execute Step S202at timing at which the display stop condition table and the stop OR condition table are updated. Alternatively, the image processing device10may determine whether the termination condition is satisfied by determining all the display stop conditions at timing at which Step S202is executed.

As described above, in a case where a screen other than the virtual viewpoint screen is displayed on the display unit31, the image processing device10changes the display of the display unit31to the notification screen200when the switching condition to the notification screen200is satisfied. As a result, the image processing device10can appropriately notify a driver of an obstacle in the case of requiring a notification.

4. Alternative Example

In the embodiment described above, although the image processing device10determines whether a driver is notified of an obstacle after the detector40detects the obstacle, the present embodiment is not limited to the above. For example, when the display unit31does not display a virtual viewpoint screen including the synthesized image300and a switching condition is satisfied, the image processing device10determines that the present mode is a notification mode for notifying a driver of an obstacle. The image processing device10notifies a driver of an obstacle when receiving the detection notification of the obstacle from the detector40in a detection mode.

As described above, because the image processing device10previously switches between notification and detection modes, the image processing device10does not need to determine the satisfaction or unsatisfaction of the switching condition at timing at which an obstacle is detected, and thus can immediately notify the driver of the obstacle at timing at which the detector40detects the obstacle.

In a case where the image processing device10is in the notification mode, the image processing device10terminates the detection mode when the notification screen200is displayed on the display unit31, namely, it is determined that the display stop conditions excluding the condition of “notification screen display” ofFIG. 7are satisfied.

As described above, because the detection mode is terminated when the display stop conditions different from the display condition are satisfied, it is possible to restrain the frequent switching between the start and termination of the detection mode in a short period of time.

According to an aspect of an embodiment, it is possible to provide an image processing device and an image processing method, which can appropriately notify a driver of a vehicle of an obstacle.