Warning sign placing apparatus and control method thereof

A warning sign placing apparatus and a control method thereof are provided. The warning sign placing apparatus includes at least two camera units, a control unit, and a vehicle. The camera unit captures a plurality of images in a preset direction. The vehicle carries at least two camera units and control unit. The control unit identifies a traveling direction of the road and distinguishes at least one object on the road based on the images, and plans a route along the road for the vehicle according to the at least one object, where the vehicle travels along the route. A warning sign is configured in the warning sign placing apparatus and is able to automatically move to a preset position with a preset distance in order to avoid the risk of dangers in a case of manually placing the warning sign.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 104100517, filed on Jan. 8, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a warning sign placing technique, in particular, to an automatically movable warning sign placing apparatus and a control method thereof.

2. Description of Related Art

A car accident or breakdown may inevitably occur during traveling. The traffic law in each country requires a driver or a culprit to place a car breakdown warning triangle or other highly visible warning equipment at a distance behind the car in order to alert the oncoming cars that a car accident is ahead with an adequate reaction distance so as to prevent another accident.

A common approach is to manually carry the car breakdown warning triangle out from the car and place it behind the car with a certain distance. However, while the driver is carrying the car breakdown warning triangle, the oncoming cars may not be given with an adequate reaction distance to the car accident and may thus collide with the driver. Hence, to safely place a car breakdown warning triangle for a driver during a car accident has become a crucial problem to be solved.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a warning sign placing apparatus and a control method thereof, where a warning sign is configured in the warning sign placing apparatus and the warning sign placing apparatus is able to automatically move to a preset position with a preset distance in order to avoid the risk of dangers in a case of manually placing the warning sign.

The invention is directed to a warning sign placing apparatus including at least two camera units, a control unit, and a vehicle. The camera units are configured to capture a plurality of images in a preset direction. The control unit is coupled to the camera units. The vehicle is configured to carry the camera units and the control unit. The control unit identifies a traveling direction of a road based on the images, distinguishes at least one object on the road, and plans a route along the road for the vehicle according to the at least one object, where the vehicle travels along the route.

According to an embodiment of the invention, the warning sign placing apparatus further includes a storage unit and a receiving unit. The storage unit is coupled to the control unit and is configured to store the route. The receiving unit is coupled to the control unit and is configured to receive a recall signal. The recall signal is used to instruct the control unit for controlling the vehicle to return back along the route.

According to an embodiment of the invention, the control unit distinguishes that the at least one object includes a curb line. The control unit calculates an angle between the curb line and a preset imaginary line and controls a traveling direction of the vehicle according to the angle.

According to an embodiment of the invention, the control unit distinguishes that the at least one object includes at least one obstacle. The control unit calculates obstacle information of the at least one obstacle and plans the route for the vehicle according to the obstacle information.

According to an embodiment of the invention, the control unit stops operating while the vehicle is traveling.

According to an embodiment of the invention, the warning sign placing apparatus further includes a light-emitting unit. The light-emitting unit is coupled to the control unit and has a light-emitting range. The control unit plans the route for the vehicle according to the road within the light-emitting range.

From another viewpoint, the invention is directed to a control method of a warning sign placing apparatus, and the method includes the following steps. A plurality of images are captured by the at least two camera units in a preset direction. A traveling direction of a road is identified based on the images and determining at least one object on the road A route along the road for the vehicle is planned according to the at least one object, wherein the vehicle travels along the route.

Other detailed embodiments of the control method of the warning sign placing apparatus may refer to the previous discussion and may not be repeated herein.

In summary, in the warning sign placing apparatus and the control thereof proposed in the invention, a plurality of images are captured in a preset direction, a traveling direction of the road is identified based on the images, and at least one object on a road is distinguished. A route along the road for the vehicle is planned according to the at least one object so that the vehicle may travel along the planned route in order to avoid the risk of dangers in a case of manually placing the warning sign.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1illustrates a block diagram of a warning sign placing apparatus according to an embodiment of the invention. Referring toFIG. 1, a warning sign placing apparatus10includes two camera units102and104, a control unit106, and a vehicle108. A warning sign may be placed on the vehicle108in the present embodiment.

The camera units102and104are configured to capture images in a preset direction. To be specific, the camera units102and104may capture images in a same direction. For example, the camera units102and104may be configured at a same side of the vehicle108, and each of the camera units102and104may capture a front scene thereof. Moreover, the camera units102and104may be configured with a distance therebetween. For example, the camera units102and104may be configured at a same side of the vehicle108with a space of 20 cm therebetween. Therefore, the camera units102and104may have different fields of view. It should be noted that, the camera units102and104may be configured at different sides or other positions of the vehicle108. The number, the size, and the arrangement of the camera units are not limited in the invention. The camera units102and104may be cameras or camcorders with charge coupled device (CCD) lenses, complementary metal oxide semiconductor transistor (CMOS) lenses, or infrared lenses, and yet the invention is not limited thereto.

The control unit106is coupled to the camera unit102and camera unit104. The control unit106may be a control chip, a microprocessor, or other suitable controllers.

The vehicle108is configured to carry the camera unit102, the camera unit104, and the control unit106. The vehicle108is also configured to carry the warning sign and may include a substrate and drive elements such as a plurality of motors and wheels. In the present embodiment, the control unit107may identify a traveling direction of a road based on the images, distinguish all objects on the road, and plan a route along the road for the vehicle according to the objects. Then, the vehicle is able to travel along the planned route.

In an embodiment of the invention, the warning sign placing apparatus10may further include a storage unit110and a receiving unit112, and the storage unit110is coupled to the control unit106. The storage unit110is configured to store the route planned by the control unit106. The storage unit110may be a built-in or an external storage unit. The built-in storage unit may be, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, or a magnetic disk storage device. The external storage unit may be, for example, a compact flash (CF) memory card, a secure digital (SD) memory card, a micro SD memory card, or a memory stick (MS). The receiving unit112is coupled to the control unit106. The receiving unit112may a receiver employing a radio frequency (RF) technology or other wireless technologies. The receiving unit112is configured to receive a recall signal. In an embodiment, the recall signal may be used to instruct the control unit106for controlling the vehicle108to return back along the planned route. From another point of view, the recall signal may be used to instruct the control unit106for controlling the vehicle108to return back according to the route stored in the storage unit110.

In an embodiment of the invention, the warning sign placing apparatus10may further include a light-emitting unit114coupled to the control unit106. The light-emitting unit114may be an infrared light-emitting diode (LED). The light-emitting unit114has a light-emitting range and is configured to provide illumination. The type, number, size, and configuration of the limit-emitting unit144are not limited in the invention. To be specific, during insufficient ambient light or at night, the light-emitting unit114may assist the camera units102and104in capturing images with clarity. In other words, the images captured by the camera units102and104within the light-emitting range may have better luminance contrast.

FIGS. 2A-2Cillustrate structural schematic diagrams of a warning sign placing apparatus according to an embodiment of the invention.FIG. 2Aillustrates a front view diagram of the outer structure of the warning sign placing apparatus.FIG. 2Billustrates a side view diagram of the outer structure of the warning sign placing apparatus.FIG. 2Cillustrates a top view diagram of the outer structure of the warning sign placing apparatus. Referring toFIGS. 2A-2C, the outer structure of the sign warning placing apparatus includes the camera unit102, the camera unit104, the vehicle108, the receiving unit112, the light-emitting unit114, drive elements T1, and a warning sign A1. It should be noted that, the camera unit102, the camera unit104, the vehicle108, the receiving unit, and the light-emitting unit114provide similar or same features as those components with same reference numbers inFIG. 1and thus their features would not be repeated hereinafter. The drive elements T1may be a plurality of wheel structures (e.g. steering wheels) driven by a motor. The drive elements T1are configured at the bottom of the vehicle108and may be driven by the control unit106to move the vehicle108. The warning sign A1may be a car breakdown warning triangle with a plurality of highly emitting elements such as LED. The warning sign A1may also be a warning sign or a notice board in other forms. The shape, color, size, representation of the warning sign A1are not limited in the invention. It should be noted that, the outer structure of the warning sign placing apparatus illustrated in the present embodiment is merely an example. Each component of the warning sign placing apparatus10may be arranged according to actual usage. The appearance and representation of the warning sign placing apparatus are not limited in the invention.

FIG. 3illustrates a flowchart of a control method of a warning sign placing apparatus according to an embodiment of the invention. Referring to bothFIG. 1andFIG. 3, the user may first place the warning sign placing apparatus10on a floor of a car's rear and allow the camera units102and104to be facing at an opposite direction to a traveling direction of the car. In Step S301, each of the camera units102and104may capture a plurality of images of a front scene thereof. To be specific, the camera units102and104may respectively capture the images with different fields of view. In Step S303, the control unit106may identify a traveling direction of a road based on the aforesaid images and distinguish at least one object on the road. For simplicity and illustrative purposes, the at least one object would be plural in the following embodiments. The objects may include road surfaces, curb lines, boundary lines, traffic lines, and obstacles such as holes, pits, or rocks. The types and the patterns of the objects to be distinguished are not limited in the invention. In Step S305, the control unit106may plan a route along the road for the vehicle108according to the aforesaid objects, where the vehicle may travel along the route.

For example,FIG. 4illustrates a schematic diagram of a control method of a warning sign placing apparatus. Referring toFIG. 4, the schematic diagram includes the warning sign placing apparatus10, a region402, a region404, a boundary line406, a boundary line408, an obstacle410, an obstacle412, a region414, a route416, and a target point418. The fields of view of the camera units102and104may respectively be the regions402and404. The light-emitting range of the light-emitting unit114may be the region414. To be specific, the camera units102and104of the warning sign placing apparatus10may respectively capture images within the regions402and404. The control unit106of the warning sign placing apparatus10may analyze the aforesaid images and distinguish the objects in the images such as the boundary line406, the boundary line408, the obstacle410, and the obstacle412. The control unit106may plan the route416for the vehicle108according to the aforesaid objects and control the vehicle108to travel to the target point418to place the warning sign.

In an embodiment, the control unit106may determine that the objects include at least one obstacle, calculate obstacle information of the obstacle(s), and plan a route for the vehicle according to the obstacle information.

To be specific,FIG. 5illustrates a schematic flowchart of distinguishing an obstacle by a warning sign placing apparatus according to an embodiment of the invention. Referring toFIG. 5, in Step S501, the control unit106may distinguish that the objects include at least one obstacle, where the obstacle(s) may include rocks protruding from a road, or holes and pits on the road. For simplicity and illustrative purposes, the at least one obstacle would be plural in the following embodiments. In Step S503, the control unit106may calculate obstacle information of the obstacles. Since the reflectivity of each object is different, all the objects in the images may be presented in different variations of luminance contrast. Different objects may be determined by analyzing the images with different fields of view according to color blocks presented therein. Moreover, information such as size, shape, position, and depth of each color block may be calculated by using triangulation calculation. Hence, the obstacle information may be, for example, information such as the cross-sectional areas, the sizes, the shapes, the positions, and the depths of the objects, and yet the obstacle information is not limited thereto. In Step S505, the control unit106may plan a route for the vehicle108according to the obstacle information. The warning sign placing apparatus10may avoid all adverse conditions along the road and arrive at a position with a suitable safety distance.

For example,FIG. 6illustrates a schematic image of determining obstacles by a warning sign placing apparatus according to an embodiment of the invention. Referring toFIG. 6, the schematic image includes a boundary line602, a boundary line604, an obstacle606, an obstacle608, a preset imaginary line610, a target point612, and a line segment614. To be specific, after the control unit106may analyze different images with different fields of view, it may identify all the objects such as the boundary line602, the boundary line604, the obstacle606, and the obstacle608and further distinguish the obstacle606and the obstacle608among the determined objects. The control unit106may calculate obstacle information of the aforesaid obstacles. For example, a same obstacle may be calculated based on triangulation according to the images with different fields of view to obtain the depth of the obstacle. The control unit106may also obtain the length and width distances of the obstacle through image analysis and calculate the coordinate of the obstacle with respect to the vehicle accordingly. Lastly, the control unit106may plan a route for the vehicle108according to the obstacle information.

In an embodiment, the control unit106may define a target point and plan a route according to the target point. To be specific, such target point may be a position on a road at which the warning sign placing apparatus10would be placed. The target point612may be set in the image by the camera units102and104, or the control unit106. For example, referring toFIG. 6, the preset imaginary line610may be a central axis of the image or a middle line between the boundary line602and the boundary line604. Also, the line segment614is between the boundary line602and the boundary line604. The depth of the line segment614in the image may correspond to a position with a suitable safety distance where the warning sign placing apparatus10would be placed. In other words, the control unit106may set the target point612according to the preset imaginary line610and the line segment614. For example, the target point612may be set at an intersection of the preset imaginary line610and the line segment614. The target point612may also be set at any position on the line segment614. In other words, the warning sign placing apparatus10may set the current position as a starting point and the target point612as a destination for route planning.

It should be noted that, the number of the target point is not restricted to one. The warning sign placing apparatus10may execute the aforesaid flow by segments, move to each target point of the segments, and arrive at a position with a suitable safety distance. For example, when the planned route is on a curved road, the warning sign placing apparatus10may execute the aforesaid flow repeatedly, move to a target point in each segment, and arrive at a position with a suitable safety distance.

In an embodiment, the control unit106may plan a route for the vehicle according to a road within the light-emitting range of the light-emitting unit114. The present embodiment may be applicable during insufficient ambient light or at night, and yet the invention is not limited thereto. To be specific, the planned route is more accurate when the images including the objects to be distinguished are clearer. The camera units102and104may obtain the images with better luminance contrast on the road within the light-emitting range. Moreover, the control unit106may define the length and range of the route according to the light-emitting range. To be specific, the range outside of the light-emitting range in the image may be completely dark, and thus the control unit106may plan the route within the visible range. For example, the length of the route planned by the control unit106may be equal to a light-emitting distance. The range of the route planned by the control unit106may be equal to the light-emitting range.

For example,FIG. 7illustrates a schematic diagram of a control method of a warning sign placing apparatus. Referring toFIG. 7, the schematic diagram includes the warning sign placing apparatus10, a boundary line702, a boundary line704, a region706, a target point708, a target point710, a target point712, a target point714, and a target point716, where the light-emitting range of the light-emitting unit114of the warning sign placing apparatus10may be the region706. To be specific, the control unit106may set each preset distance segment according to the light-emitting range and set the target points708,710,712,714, and716according to the preset distance segments. For example, the light-emitting range may be 5 m, and thus each of the preset distance segments may also be 5 m. That is, a target point is set every 5 m.

After the aforesaid method is repeatedly executed, the warning sign placing apparatus10may arrive at a position with a suitable safety distance of 25 m, i.e. the target point716.

It should be noted that, the control unit106may stop operating while the vehicle108is traveling. To be specific, the control unit106may enter its sleep state after transmitting the route to the vehicle108so as to save the power. The control unit106may enter its start-up state after the vehicle108arrives at the target point. Moreover, the control unit106may enter its start-up state after receiving a recall instruction.

In an embodiment, the control unit106may identify that the distinguished objects include a curb line. The control unit106may calculate an angle between the curb line and a preset imaginary line and control a traveling direction of the vehicle108according to the angle. To be specific, the curb line may include a lane line, a lane/road curb line, and a lane boundary. It may be a solid line, a dashed line, or a boundary between two different road surfaces. The curb line may be configured to define the range for planning a route. The preset imaginary line may also be configured to plan a route. The preset imaginary line may be set in the images by the camera units104and106or by the control unit106. There may also be plural preset imaginary lines extended from each road surface with different quantities and spacing intervals. The preset imaginary lines may be solid lines or dashed-lines. The number, the width, the size, the color, and the pattern of the preset imaginary lines are not limited herein. The control unit106may calculate all angles between the curb line and the predetermined imaginary lines so as to determine the traveling direction of the vehicle108.

FIG. 8illustrates a schematic flowchart of determining a travelling direction by a warning sign placing apparatus. Referring toFIG. 8, in Step S801, the control unit106may compare images and identify that the distinguished objects include a curb line. In Step S803, the control unit106may calculate an angle between the curb line and the preset imaginary line, and thereby obtain a traveling direction of the warning sign placing apparatus10. In Step S805, the control unit106may control the traveling direction of the warning sign placing apparatus10. Hence, the control unit106may prevent the warning sign placing apparatus10from crossing over the curb line and affecting the cars on other lanes. Moreover, the flow for determining the traveling direction may be repeated if necessary.

It should be noted that, the control unit106may determine whether to adjust the traveling direction in advance according to the angle. To be specific, while the user is placing the warning sign placing apparatus10, the placement position of the warning sign placing apparatus10may be shifted due to road conditions such as a wet, a rising, or a decline road surface and thereby affect the captured images and the route planned by the control unit106. The control unit106may identify the current direction to which the camera units102and104are facing and determine whether the information captured in the images is sufficient for route planning so as to decide whether to adjust the traveling direction of the vehicle108. When the control unit106determines that the information captured in the images is not sufficient for route planning, the control unit106would adjust the traveling direction of the vehicle108according to the angle. When the control unit106determines that the information captured in the images is sufficient for route planning, the control unit106would not adjust the traveling direction of the vehicle108. For example, when the control unit106determines that the angle between the boundary line and the preset imaginary line is less than a preset threshold, it indicates that the warning sign placing apparatus10is facing towards a direction which is parallel to the lane, and thus the traveling direction of the warning sign placing apparatus10would not be adjusted. In other words, when the control unit106determines that the angle between the boundary line and the preset imaginary line is not less than the preset threshold, it represents that the camera units of the warning sign placing apparatus10may be facing towards, for example, the lane or the boundary line. The captured images of the warning sign placing apparatus10in this case does not provide sufficient information for route planning such as a placement of a target point. Hence, the control unit106may control the vehicle108to adjust the orientation of the vehicle108based on the aforesaid angle. For example, the control unit106may rotate the vehicle108so that the camera units102and104are facing towards the target point.

For example,FIG. 9AandFIG. 9Billustrate schematic diagrams of a road while a warning sign placing apparatus is determining a traveling direction according to an embodiment of the invention.FIG. 9Aillustrates a schematic diagram of a scene which the warning sign placing apparatus10is facing toward. Referring toFIG. 9A, the schematic diagram includes the warning sign placing apparatus10, a region902, a region904, a curb line906, and a curb line908, where the fields of view of the camera units102and104may respectively be the region902and the region904.FIG. 9Billustrates a schematic diagram of an image to be determined by the warning sign placing apparatus10illustrated inFIG. 9A. Referring toFIG. 9B, the schematic diagram includes the curb line906, the curb line908, a plurality of preset imaginary lines920and an angle922, where a preset imaginary line924is a central axis of the image. To be specific, the control unit106may identify the curb line906and curb line908. The control unit106may calculate that the angle922between the curb line906and the preset imaginary line920and the angle922between the curb line908and the preset imaginary line920are θ. The control unit106may control the traveling direction of the vehicle108according to the angle922(i.e. θ). In the present embodiment, the control unit106may control the vehicle108to rotate according to the angle922(i.e. θ) so that the camera units are facing toward a direction which is parallel to the lane.

FIG. 10AandFIG. 10Billustrate schematic diagrams of a road while a warning sign placing apparatus is determining a traveling direction according to an embodiment of the invention.FIG. 10Aillustrates a schematic diagram of a scene which the warning sign placing apparatus10is facing toward. Referring toFIG. 10A, the schematic diagram includes the warning sign placing apparatus10, a region1002, a region1004, a curb line1006, and a curb line1008, where the fields of view of the camera units102and104may respectively be the region1002and the region1004.FIG. 10Billustrates a schematic diagram of an image to be determined by the warning sign placing apparatus10illustrated inFIG. 10A. Referring toFIG. 10B, the schematic diagram includes the curb line1006, the curb line1008, a plurality of preset imaginary lines102, and an angle1002, where a preset imaginary line1024is a central axis of the image. To be specific, the control unit106may identify the curb line1006and the curb line1008. The control unit106may calculate that the angle1022between the curb line1006and the preset imaginary line1020and the angle1022between the curb line1008and the preset imaginary line1020are θ. The control unit106may control the traveling direction of the vehicle108according to the angle1022(i.e. θ). In the present embodiment, the control unit106may determine that the information in the images captured by the camera units is sufficient for route planning according to the angle1022(i.e. θ), and thus the traveling direction of the vehicle108may not need to be adjusted in advance.

It should be noted that, traffic lines on some roads may not be clearly presented, and thus curb lines may be distinguished by comparing the luminance of color blocks in an image. To be specific, the reflectivity of different materials of road surfaces, such as a blacktop road surface, a brick sidewalk, a lawn, or a concrete road surface, may be different. Hence, the color blocks with different luminance contrast may be presented in the image, where the boundary between different color blocks may be identified as the curb lines.

For example,FIG. 11AandFIG. 11Billustrate schematic diagrams of a road while a warning sign placing apparatus is determining a curb line according to an embodiment of the invention.FIG. 11Aillustrates a schematic diagram of road surfaces. The schematic diagram includes a road surface1102and a road surface1104. The road surface1102may be a blacktop road surface, and the road surface1106may be a brick sidewalk.FIG. 11Billustrates a schematic diagram of an image extracted from the road scene inFIG. 11A. The schematic diagram includes a color block1112, a color block1114, a plurality of preset imaginary lines1120, and a boundary line1122, where the road surface1102inFIG. 11Acorresponds to the color block1112, and the road surface1104corresponds to the color block1114. The boundary line1122may be obtained by identifying the boundary of the two color blocks. Hence, the curb line may still be identified when there exists no clear traffic lines.

In view of the foregoing, in the warning sign placing apparatus and the control thereof proposed in the invention, images are captured by using at least two lenses, objects in the images are identified, and a traveling route of the warning sign placing apparatus is planned. Accordingly, the warning sign placing apparatus would automatically move to a position with a suitable safety distance according to the route, and people's safety would be ensured. The warning sign placing apparatus in the invention may distinguish curb lines and obstacles from the images as well as calculate obstacle information, and thus it may automatically move to a preset distance for placement in any weather or road conditions based on artificial intelligence. Moreover, the warning sign placing apparatus in the invention may also receive a recall signal and return back along the original route to ensure people's safety.