JP2007172540A - Moving object discrimination system, moving object discrimination method, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moving object discrimination system and moving object discrimination method for discriminating an approaching moving object more easily and reliably than before on a road with low visibility, such as a blind spot at an intersection or a blind curve, and a computer program for executing the moving object discrimination method by a computer. <P>SOLUTION: A CPU 28 calculates an average value of a motion vector direction of a pixel in a connection block and specifies the calculated average value as a moving direction of the connection block. The CPU 28 calculates an angle difference between the specified moving direction and a predetermined approaching direction, when the calculated angle difference is equal to a second threshold value or smaller, generates a display image, and combines it into a picked-up image. Thus, when it is decided that there is a moving object which is on the picked-up image and is moving in the approaching direction, display information for highlighting the moving object is added. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention realizes a moving object determination system, a moving object determination method, and a moving object determination method for determining the presence of a moving object based on a captured image obtained by imaging an area including a road with an imaging device. It relates to a computer program.

  One of the main causes of accidents in which a vehicle, a two-wheeled vehicle or a pedestrian, etc., approaches a blind spot at an intersection or a curve with poor visibility, is a road condition in which a target object such as a vehicle, two-wheeled vehicle or pedestrian is difficult to recognize. It is done. As countermeasures, conventionally, a convex mirror is installed at the intersection so that the driver can recognize an object approaching from the left and right, and a convex mirror is installed so that the driver can recognize an object coming from the front even in a curve with poor visibility. is set up.

  However, when a pedestrian is wearing dark clothes, the image reflected on the convex mirror has low contrast, so it is difficult to see, or when an object that approaches is overlooked due to distraction. Not a little. For this reason, in order to reduce accidents due to these factors, there is a need for a device or system that makes it easier for the driver to recognize the presence of an object that may approach a curve or intersection with poor visibility and that may cause a collision. .

  For example, an imaging device installed at a plurality of monitoring points images the traffic situation at each monitoring point, and transmits image information obtained by imaging to the information center. The information center transmits the image information to the in-vehicle device of the vehicle via the road beacon device. In an in-vehicle device, a traffic information providing system has been proposed that allows a driver to arbitrarily select an image to be displayed and check the state of an intersection or road to be checked (see Patent Document 1).

  In addition, a camera for photographing the priority road is installed at the intersection including the priority road and the non-priority road, and a projector / receiver for providing video information to a vehicle entering the intersection on the non-priority road is installed. By transmitting the image captured by the camera as image information from the projector / receiver to the in-vehicle device of the vehicle and displaying the image information received by the in-vehicle device on the display unit, There has been proposed a vehicle accident prevention system that can prevent a vehicle accident such as a bicycle or a vehicle and can improve the convenience of transportation (see Patent Document 2).

Further, the vehicle includes a roadside device installed at an intersection and an in-vehicle device mounted on a vehicle. The roadside device includes an imaging unit that captures the area around the intersection, an encoding unit that encodes a captured image, and an encoded image. A transmission unit that wirelessly transmits the received video to the in-vehicle device, the in-vehicle device receiving the video transmitted from the roadside device wirelessly, a decoding unit that decodes the received video, and a decoding A display unit for displaying the recorded video. As a result, a traffic video presentation system has been proposed in which an occupant of a vehicle can clearly grasp the situation around the intersection before entering the intersection at an intersection with poor visibility (see Patent Document 3).
Japanese Patent Laid-Open No. 9-180087 JP 2003-109199 A JP 2004-94862 A

  However, in the systems disclosed in Patent Documents 1 to 3, the image captured by the image capturing device is only transmitted to the in-vehicle device of the vehicle. When the moving object on the image has low contrast, it is difficult to visually recognize the moving object. It remains. In addition, moving objects on the image may be overlooked, and the vehicle driver approaches a vehicle, a two-wheeled vehicle or a pedestrian closer to the intersection than the blind spot, or a vehicle, a two-wheeled vehicle or a walking approached from the front of a curve with poor visibility. Therefore, there has been a demand for a system that can reliably recognize a person or the like. In addition, in recent years, a system for performing an inter-vehicle communication and exchanging information on a vehicle position, a traveling direction, or a speed acquired by GPS and avoiding an accident has been proposed. It is necessary to provide a communication device for vehicle-to-vehicle communication in this vehicle, and practical application is difficult.

  The present invention has been made in view of such circumstances, and identifies a connected block formed by connecting pixels whose angle difference between motion vectors of pixels of a captured image is equal to or less than a first threshold. It is possible to generate display information for highlighting a moving body corresponding to the above, and to output the composite of the generated display information with a captured image and output it, thereby making it possible to see visibility such as blind spots at intersections or curves with poor visibility. To provide a moving body determination system, a moving body determination method, and a computer program for realizing the moving body determination method by a computer that can determine a moving body approaching on a low road more easily and reliably than in the past. Objective.

  Another object of the present invention is provided with calculation means for calculating an angle difference between the direction of the motion vector of the connected block and the approach direction on the captured image corresponding to the direction in which the moving body approaches the image capturing apparatus. When the detected angle difference is equal to or smaller than the second threshold, it is an object of the present invention to provide a moving body determination system that can improve the visibility of only a moving body with a possibility of collision by generating display information.

  Another object of the present invention is provided with transmission means having directivity in the transmission direction, and determination means for determining a direction on a road that can collide with a moving body that moves in a direction approaching the imaging device. To provide a moving body determination system that can reliably determine a moving body that may collide by transmitting a captured image combined with display information to an in-vehicle device that moves in the determined direction. It is in.

  Another object of the present invention is provided with a transmission unit installed on one road and a determination unit that determines a direction on the road that can collide with a moving body that moves in a direction approaching the imaging device. The mobile body determination that can reliably determine the mobile body that may collide by transmitting the captured image combined with the display information to the in-vehicle device that moves in the determined direction on the one road. To provide a system.

  Another object of the present invention is to calculate a first motion vector based on a block matching method using a pixel block for each of captured images at different imaging time points, and to correspond to the calculated first motion vector. A second motion vector is further calculated based on the gradient method using the local region in each of the new captured image obtained by moving and the other captured images having different imaging time points, and the calculated first and second It is an object of the present invention to provide a moving body determination system capable of accurately determining the presence of a moving body regardless of the magnitude of the movement of the moving body.

  Another object of the present invention is to increase the distance to the moving body by increasing the size of the pixel block or the local area in the area corresponding to the short distance than the area corresponding to the long distance of the captured image. It is an object of the present invention to provide a moving body determination system capable of accurately determining the presence of a moving body over a wide range.

  Another object of the present invention is to calculate a motion vector based on a gradient method using a local region for each captured image at different capturing points in a region corresponding to a long distance of the captured image, and In the area corresponding to, the motion vector is accurately calculated over a wide range regardless of the distance to the mobile object by calculating the motion vector based on the block matching method using the pixel block for each of the captured images having different image capturing time points. It is an object of the present invention to provide a moving body determination system that can determine the presence of a mobile object.

  Another object of the present invention is to form the pixel block or the local region in a horizontally long rectangular shape so that the pixel block or the local region is accurately affected without being affected by a motion vector that varies depending on the height from the road surface of the moving body. An object of the present invention is to provide a moving body determination system capable of determining the presence of a moving body.

  Another object of the present invention is to provide a mobile object determination system that can determine the existence of a mobile object at multiple points or remote points in a concentrated manner by providing means for acquiring a motion vector of a pixel of a captured image. It is to provide.

  A mobile body determination system according to a first aspect of the present invention is an imaging device that captures an area including a road, and a mobile body determination device that determines the presence of a mobile body based on a captured image obtained by capturing with the imaging device. In the moving body determination system, the moving body determination device includes: a specifying unit that specifies a connected block formed by connecting pixels having a motion vector angle difference of a captured image that is equal to or less than a first threshold; Based on the connected block, a means for determining the presence of the moving body, a generating means for generating display information for highlighting the determined moving body, and the generated display information are combined with the captured image and output. Output means.

  The moving body determination system according to a second aspect of the present invention is the moving body determination system according to the first aspect, wherein storage means for storing an approach direction on a captured image corresponding to a direction in which the mobile body approaches the imaging device, and a direction of a motion vector of the connection block And calculating means for calculating an angle difference between the approaching direction and the generating means for generating display information when the angle difference calculated by the calculating means is equal to or less than a second threshold value. It is characterized by.

  According to a third aspect of the present invention, there is provided the mobile body determination system according to the second aspect, wherein a transmission unit having directivity in a transmission direction and a direction on a road that can collide with a mobile body that moves in a direction approaching the imaging device. A determination unit configured to determine, wherein the transmission unit is configured to transmit a captured image obtained by combining display information to an in-vehicle device that moves in the direction determined by the determination unit.

  According to a fourth aspect of the present invention, there is provided the mobile body determination system according to the second aspect, wherein a transmission unit installed on one road and a direction on the road that can collide with a mobile body that moves in a direction approaching the imaging device. Determination means, and the transmission means is configured to transmit a captured image obtained by combining display information to an in-vehicle device that moves on the one road in the direction determined by the determination means. And

  The moving body determination system according to a fifth aspect of the present invention is the block matching using the pixel block in each of the first captured time point and the second captured time point at which the captured time points are different in any of the first to fourth aspects. Based on the method, means for calculating a first motion vector of a pixel of a captured image at the first imaging time point, and imaging at the first imaging time point according to the first motion vector calculated by the means Based on a gradient method using a local area in each of the new captured image obtained by moving the pixels of the image and the captured image at the second imaging time point, the second motion vector of the pixels of the new captured image And a combined vector of the first and second motion vectors calculated by both means is used as a motion vector of a pixel of the captured image.

  In the mobile object determination system according to a sixth aspect of the present invention, in the fifth aspect, the size of the pixel block or the local region is larger in the region corresponding to the short distance of the captured image than in the region corresponding to the long distance of the captured image. It is characterized by.

  According to a seventh aspect of the present invention, there is provided a mobile body determination system according to any one of the first to fourth aspects of the present invention, based on a gradient method using a local region for each of a plurality of captured images at different imaging time points. Based on a means for calculating a motion vector of a pixel in a corresponding region and a block matching method using a pixel block in each of a plurality of captured images at different capturing points, a motion vector of a pixel in a region corresponding to a short distance of the captured image And a motion vector calculated by both means as a motion vector of a pixel of the captured image.

  In the mobile object determination system according to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, the pixel block or the local region is a horizontally long rectangular shape.

  A moving body determination system according to a ninth aspect is characterized in that, in any one of the first to fourth aspects, a means for acquiring a motion vector of a pixel of a captured image is provided.

  A moving body determination method according to a tenth aspect of the present invention is the moving body determination method for determining the presence of a moving body based on a captured image obtained by capturing an image, wherein an angle difference between motion vectors of pixels of the captured image is equal to or less than a first threshold. The connected block formed by connecting the pixels is specified, the presence of the moving object is determined based on the specified connected block, and the display information for highlighting the determined moving object is generated and generated. The display information is combined with the captured image and output.

  A computer program according to an eleventh aspect of the present invention is a computer program for causing a computer to determine the presence of a moving object based on a captured image obtained by capturing an image. Means for determining whether the angle difference calculated by the means is less than or equal to a first threshold value, and means for identifying a connected block formed by connecting pixels having the angle difference less than or equal to the threshold value And means for determining the presence of the moving object based on the identified connected block, means for generating display information for highlighting the determined moving object, and combining the generated display information with the captured image It is made to function as a means to do.

  In the first invention, the tenth invention, and the eleventh invention, a connected block in which pixels whose motion vector angle difference for each pixel of the captured image is equal to or smaller than the first threshold is specified. As a result, a moving object traveling on the road is specified by eliminating shadows, road markings, and the like on the road where there is no change in position. In addition, when specifying a connection block, the angle difference of a motion vector is below a 1st threshold value, and an adjacent pixel can also be connected. Based on the identified connected block, the presence of the moving body is determined, and the generation unit generates display information for highlighting the determined moving body. The display information includes, for example, blinking a rectangular frame surrounding the connected block, changing the color of the frame at a predetermined cycle, changing the size of the frame at a predetermined cycle, and the like. The output means outputs a captured image in which display information is synthesized. Thereby, when the presence of the moving body is determined, the determined moving body is highlighted.

  In the second invention, the calculating means calculates the angle difference between the direction of the motion vector of the identified connected block and the approaching direction on the captured image corresponding to the direction in which the moving body approaches the imaging device. The generation unit generates display information when the calculated angle difference is equal to or smaller than a second threshold value. Thereby, when the moving body corresponding to the specified connected block moves in a predetermined approach direction, the moving body is highlighted. Further, when the moving object corresponding to the identified connected block does not move in a predetermined approach direction, highlighting is not performed.

  In the third invention, the determination means determines a direction on the road that can collide with the moving body when the moving body corresponding to the specified connection block moves in a predetermined approach direction. To do. The transmission means having directivity in the transmission direction transmits the captured image combined with the display information to the in-vehicle device that moves in the determined direction. Thus, a captured image in which display information is combined is provided to a vehicle (with an in-vehicle device mounted) that may collide with a moving body that moves in the approaching direction.

  In the fourth invention, the determination means determines a direction on the road that can collide with the moving body when the moving body corresponding to the specified connection block moves in a predetermined approach direction. To do. The transmission unit installed on one road transmits the captured image combined with the display information to the in-vehicle device that moves in the determined direction on the one road. Thus, a captured image in which display information is combined is provided to a vehicle (with an in-vehicle device mounted) that may collide with a moving body that moves in the approaching direction.

  In the fifth aspect of the invention, block matching using a pixel block (for example, composed of a pixel of interest and its surrounding pixels) in each of the captured images at the first imaging time point and the second imaging time point that are different from each other in image capturing time point. Based on the method, a position change in the captured image of the pixel block is obtained, and a first motion vector of the pixel of the captured image at the time of the first imaging is calculated. In accordance with the calculated first motion vector, a local area is used for each of a new captured image obtained by moving pixels of the captured image at the first imaging time point and a captured image at the second imaging time point. Based on the gradient method, the second motion vector of the pixel of the new captured image is calculated under the constraint that the optical flow in the local region is constant, and the second motion vector calculated by the block matching method and the gradient method is calculated. A motion vector is calculated by combining the first and second motion vectors.

  In the sixth invention, in the region corresponding to the long distance of the captured image (that is, the region where the distance to the vehicle is long in the captured image), the size of the pixel block or the local region is reduced to reduce the proximity of the captured image. In the area corresponding to the distance (that is, the area where the distance to the vehicle is close in the captured image), the size of the pixel block or the local area is increased. Thereby, the size of the pixel block or the local region is brought close to the size of the moving body in the captured image.

  In the seventh invention, in the region corresponding to the long distance of the captured image, the motion vector of the pixel is calculated based on the gradient method using the local region for each of the captured images at different capturing points. Accordingly, the motion vector is calculated even if the motion of the pixel is small, for example, even if it is a minute motion of less than one pixel. On the other hand, in the region corresponding to the short distance of the captured image, the motion vector of the pixel is calculated based on the block matching method using the pixel block for each captured image with different capturing time points. Thereby, a motion vector having a larger pixel motion is calculated.

  In the eighth invention, the pixel block or the local region is formed in a horizontally long rectangular shape. Thereby, when calculating the motion vector in the connected block, the influence of the height from the road surface of the moving body portion or the distance to the moving body portion that varies depending on the vertical direction of the pixel block or the local region is reduced. However, the size of a required pixel block or local area is secured.

  In the ninth invention, a motion vector calculated in advance is acquired.

  In the first invention, the tenth invention, and the eleventh invention, a connected block formed by connecting pixels whose angle difference of motion vectors of pixels of the captured image is equal to or less than the first threshold is specified and specified connection By providing output means for determining the presence of a moving body based on the block, generating display information for highlighting the determined moving body, and combining the generated display information with a captured image and outputting the same. On roads with low visibility, such as blind spots at intersections or curves with poor visibility, even a low-contrast moving object can be determined with high accuracy, and by highlighting the determined moving object, the mobile object is overlooked Etc. can be reduced, and the moving body can be reliably determined.

  In the second invention, there is provided a calculating means for calculating an angle difference between the direction of the motion vector of the connected block and the approaching direction on the captured image corresponding to the direction in which the moving body approaches the imaging device. When the angle difference is less than or equal to the second threshold, by generating display information, it is possible to highlight only the approaching moving body to reduce oversight, and to move away from the collision object By not highlighting, unnecessary warnings can be suppressed, and the visibility of only a moving object with a possibility of collision can be improved.

  In the third invention, there is provided a transmission means having directivity in the transmission direction, and a determination means for determining a direction on the road that can collide with a moving body moving in a direction approaching the imaging device, and display information Is transmitted to the in-vehicle device that moves in the determined direction, for example, approaches a position where the image of the convex mirror installed on the intersection with a blind spot or a poor-looking curve can be visually recognized. By this, it is possible to determine the presence or absence of a moving body that is approaching, and it is possible to reliably determine a moving body that has a possibility of a collision and to perform safer danger avoidance.

  According to the fourth aspect of the invention, there is provided transmission means installed on one road, and determination means for determining a direction on the road that can collide with a moving body that moves in a direction approaching the imaging device. Is transmitted to an in-vehicle device that moves in the determined direction on the one road, for example, an image of a convex mirror installed on a crossing road with a blind spot or a curve with poor visibility is visually recognized. It is possible to determine the presence or absence of an approaching moving body before approaching a position where it can be made, and to reliably determine a moving body that may collide, thereby enabling safer risk avoidance.

  In the fifth invention, the first motion vector is calculated based on the block matching method using the pixel blocks of the captured images at the first imaging time point and the second imaging time point at which the imaging time points are different. A gradient method using a local region in each of a new captured image obtained by moving pixels of the captured image at the first imaging time point and a captured image at the second imaging time point corresponding to the first motion vector Based on the above, the second motion vector is further calculated, and the calculated first and second motion vectors are combined into a motion vector. However, the existence of the moving object can be determined with high accuracy.

  In the sixth aspect of the invention, the size of the pixel block or the local area is made larger in the area corresponding to the short distance than the area corresponding to the long distance of the captured image, so that regardless of the distance to the moving body. It is possible to accurately determine the presence of the moving object over a wide range.

  In the seventh invention, in a region corresponding to a long distance of the picked-up image, a motion vector is calculated based on a gradient method using a local region for each picked-up image at different pick-up points, and corresponds to a short distance of the picked-up image In a region to be captured, the presence of a moving object can be accurately detected over a wide range regardless of the distance to the moving object by calculating a motion vector based on a block matching method using a pixel block for each captured image at different imaging time points. Can be determined.

  In the eighth invention, the pixel block or the local region is formed in a horizontally long rectangular shape, so that the moving object can be accurately obtained without being affected by the motion vector that varies depending on the height of the moving object from the road surface. Can be determined.

  In the ninth aspect of the invention, by providing means for acquiring the motion vector of the pixel of the captured image, there is a case where an intersection with a blind spot or a curve with poor visibility is at a remote point or at many points. However, it is possible to centrally determine the presence of the moving object at those points. In addition, adjustment of the angle of view of the video camera and maintenance of the video camera can be handled intensively. For this reason, the cost reduction of the whole system is realizable.

Embodiment 1
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is a schematic diagram showing an outline of a moving object determination system according to the present invention. In the figure, the mobile body determination system includes a video camera 1, a mobile body determination device 2, a wireless transmission device 3, and the like. The video camera 1 is installed in the mirror surface, the lower part, the side surface, and the like of the convex mirror 4 installed in the vicinity of the intersection, and images a region including a road. As shown in the figure, for example, an intersection E is assumed to intersect roads A, B, C, and D, for example. The optical axis of the video camera 1 is, for example, the direction of the road so as to image moving bodies (vehicles, two-wheeled vehicles, pedestrians, etc.) existing within a range (moving body determination range) of about 50 m from the intersection E of the roads A and B. It is arranged along. Even when the convex mirror 4 is not installed, the video camera 1 can be installed so that a required moving body determination range can be imaged.

  A moving body determination device 2 is connected to the video camera 1. The moving body determination device 2 processes a captured image obtained by capturing with the video camera 1 to determine the presence of the moving body, and outputs a captured image in which the determined moving body is highlighted. A wireless transmission device 3 is connected to the moving body determination device 2. The wireless transmission device 3 has directivity in the transmission direction of radio waves, and can transmit information to a vehicle in a range of about 50 m from the intersection E of the road C that intersects the intersection E, for example. .

  FIG. 2 is a block diagram showing a configuration of the moving body determination device 2. In the figure, reference numeral 1 denotes a video camera. The video camera 1 outputs a captured image obtained by imaging to the image input unit 21 as a video signal (analog signal). The image input unit 21 outputs the acquired video signal to the A / D conversion unit 22, and the A / D conversion unit 22 converts the input video signal into a digital signal, which is converted under the control of the CPU 28. The obtained digital signal is stored in the image memory 23 as image data. The CPU 28 uses the captured image input from the video camera 1 via the image input unit 21 as image data in synchronization with the frame rate of the video camera 1 (interval at the time of imaging, for example, 30 frames per second). The data is stored in the image memory 23 in units of frames (for example, 480 × 640 pixels).

  The auxiliary storage unit 27 stores the computer program PG recorded on the CD-ROM 29 in the RAM 24 by inserting the CD-ROM 29 on which the computer program PG of the present invention is recorded. The CPU 28 executes the computer program PG stored in the RAM 24. The moving body determination device 2 implements a motion vector calculation process, a moving body determination process, and the like described later by reading the computer program PG recorded in the CD-ROM 29 into the RAM 24 and executing the read computer program PG with the CPU 28. To do. Note that the CPU 28 can repeat predetermined processing while the moving object is in the moving object determination range.

  The image memory 23 stores the captured image acquired via the image input unit 21 as image data for each frame.

  The storage unit 26 stores the motion vector calculation result and the moving object determination processing result obtained by executing the computer program PG by the CPU 28 corresponding to each frame. In addition, the storage unit 26 stores an approach direction for specifying a direction in which the moving body approaches the intersection E on the captured image.

  The communication unit 25 outputs to the wireless transmission device 3 information related to the moving object determined by the moving object determination device 2, more specifically information related to a captured image obtained by combining display information that highlights the moving object. In addition, when outputting a captured image to the wireless transmission device 3, a captured image can also be compressed and output.

  The wireless transmission device 3 has a predetermined directivity in the radio wave transmission direction, and transmits information related to the captured image output from the mobile body determination device 2 to an in-vehicle device (not shown) of the vehicle via an antenna. .

  FIG. 3 is an explanatory diagram illustrating an example of a captured image. As shown in the figure, the moving body determination device 2 travels, for example, in a range of about 50 m from the intersection E of roads A and B, which are blind spots from the driver or passenger of the vehicle traveling from the road C toward the intersection E. The presence of the moving body is determined based on the captured image obtained by capturing the moving body with the video camera 1.

FIG. 4 is an explanatory diagram showing pixel motion vectors. As shown in FIGS. 4A and 4B, the coordinates of the pixel P _{j in} the captured image at the imaging time t _k are (x _k , y _k ), and the coordinates of the pixel P _{j in} the captured image at the imaging time t _{k + 1} are In the case of (x _{k + 1} , y _{k + 1} ), the motion vector PV _j is (x _{k + 1} −x _k , y _{k + 1} −y _k ). The time interval between different imaging points may be one frame interval or may be several frame intervals. Note that the above-described pixel may be a pixel block including a plurality of pixels. In this case, a motion vector is determined for each pixel block.

  FIG. 5 is an explanatory diagram illustrating a calculation example of the motion vector of the mobile body determination device 2. The motion vector calculation method includes a block matching method and a gradient method. In the present invention, a final motion vector is calculated by combining motion vectors (first and second motion vectors) calculated by the block matching method and the gradient method.

  First, the block matching method will be described. The block matching method uses captured images at different imaging time points (for example, time t and time t + 1). In the block matching method, in the captured image at time t, a horizontally long rectangular area centered on the pixel of interest P1 is registered as a template, and a rectangle having the same size as the template centered on an arbitrary pixel in the captured image at time t + 1 is used. A correlation value with the region is calculated, and a pixel position P2 where the calculated correlation value is maximum is detected.

  The correlation value is expressed by Equation (1) of Equation 1.

  Here, the size of the rectangular area is UxW (U and W are integers), the luminance value of the pixel at the coordinates (x, y) of the captured image at time t is I (x, y, t), −W / 2 ≦ i ≦ W / 2, −U / 2 ≦ j ≦ U / 2 (i and j are integers), and −1 ≦ correlation value ≦ 1. Equation (2) in Equation 2 is an average luminance value in the rectangular area.

  As described above, the block matching method can calculate a motion vector when the amount of motion is large by appropriately changing the size of the horizontally long rectangular region (pixel block).

  Next, the gradient method will be described. The gradient method uses a relationship between a spatial gradient of brightness (brightness) and a temporal gradient in each pixel as a method for obtaining an optical flow (motion vector field) of each frame of a moving image. That is, the gradient method is a method for obtaining an optical flow based on a gradient constraint equation (that is, a relationship equation between a spatial gradient of luminance and a temporal gradient) that assumes that the luminance distribution of a captured image is kept unchanged during movement. It is. Among the gradient methods, the spatial local optimization method is a method with particularly small calculation amount and good accuracy, which will be described below.

  The gradient method uses captured images at different imaging time points (for example, time t and time t + 1). Let the luminance of the pixel at the coordinates (x, y) of the captured image at time t be I (x, y, t). It is assumed that the pixel at the coordinate (x, y) has moved to the coordinate (x + δx, y + δy) at time t + 1 (assuming that time has elapsed by δt with respect to time t). Here, assuming that the luminance does not change, a relational expression of I (x, y, t) = I (x + δx, y + δy, t + δt) is established.

  When the right side of the above equation is Taylor-expanded, Equation (3) of Equation 3 is obtained.

  ε (x, y, t) is a higher-order term of the second or higher order, and is negligible, so this is ignored, and both sides of Equation (3) in Equation 3 are divided by δt to bring δt closer to 0. Then, Expression (4) of Expression 4 is obtained. This equation is called an optical flow gradient constraint equation.

  Here, the luminance gradient is Ix = ∂I / ∂x, Iy = ∂I / ∂y, the time gradient is It = ∂I / ∂t, the optical flow is u = δx / δt, and v = δy / δt. .

  If a constraint condition that the optical flow is constant in the required horizontally long local region (M × N) (M and N are integers) is added, it is assumed that the optical flow obtained in the local region has the same solution. Therefore, the error E is expressed by Equation (5) of Equation 5. Here, −M / 2 ≦ i ≦ M / 2 and −N / 2 ≦ j ≦ N / 2 (i and j are integers) are coordinates in the local region.

When 考 え 方 E / ∂u = 0 and ∂E / ∂v = 0 are calculated from the idea of the least square method and weighted and smoothed within the local region, Equations (6) and (7) in Equation 6 are obtained. . Here, w _{i, j} is a weighting matrix, and it is possible to use a matrix having a distribution in which the weighting increases toward the center of the local region.

  By solving the equations (6) and (7) of the equation 6, the optical flow (u, v), that is, the motion vector is represented by the equations (8), (9), and (10) of the equation 7 can get.

  As described above, since the gradient method does not require the use of a pixel block unlike the block matching method, it can be calculated even with a minute motion vector of less than one pixel.

  As shown in FIG. 5, the motion vector calculation method of the mobile body determination device 2 according to the present invention is based on the first and second imaging points at different imaging points by the block matching method. A large motion vector (first motion vector) of a pixel of the captured image at the first imaging time point is calculated using the pixel block. In accordance with the calculated motion vector, a gradient method using a local region is used for each of a new captured image obtained by moving pixels of the captured image at the first imaging time point and a captured image at the second imaging time point. A motion vector (second motion vector) is calculated, and a final motion vector is calculated by combining the motion vectors (first and second motion vectors) calculated by the respective methods. As a result, a large motion vector is calculated by the block matching method, a minute motion vector of less than one pixel that cannot be calculated by the block matching method is calculated, and the motion vectors of both are combined with high accuracy. It is possible to obtain a motion vector.

Next, the processing procedure of the mobile body determination device 2 according to the present invention will be described. FIG. 6 is a flowchart showing a processing procedure of motion vector calculation of the mobile body determination device 2. CPU28 acquires imaging point different two captured images (e.g., frames f _t of the imaging time t, the frame f _{t + 1} of the imaging time t + 1) from the image memory 23 (S10).

  The CPU 28 scans and matches the other captured image for each pixel block (for example, 7 × 15 pixels) of the acquired captured image based on the luminance value (or gradation value, etc.) of the pixel in the pixel block. A pixel block to be specified is specified (S11). When specifying a matching pixel block between two captured images, the correlation value described above can be used.

  The CPU 28 calculates a motion vector of each pixel by the block matching method based on the coordinate (position) change in the captured image of the pixel block that matches in the two captured images (S12). If there is no change in coordinates, the motion vector is zero.

  The CPU 28 generates a captured image obtained by moving each pixel by the motion vector (size and direction) according to the motion vector calculated for each pixel of the captured image at the imaging time t (S13).

  The CPU 28 calculates a motion vector by the gradient method with respect to the generated captured image and the captured image at the imaging time point t + 1 (S14), and synthesizes the motion vector calculated by the block matching method and the motion vector calculated by the gradient method. A final motion vector is calculated (S15).

  The CPU 28 calculates an angle difference between the calculated motion vectors (S16), determines whether the calculated angle difference is equal to or less than a first threshold value (S17), and the calculated angle difference is equal to or less than the first threshold value. In some cases (YES in S17), it is determined whether or not all motion vectors have been processed (S18). If all motion vectors have been processed (YES in S18), pixels having an angle difference equal to or smaller than the first threshold value are determined. Then, a connected block connecting adjacent pixels is specified (S19).

  On the other hand, if the calculated angle difference is not less than or equal to the first threshold value (NO in S17), or if all the motion vectors have not been processed (NO in S18), the CPU 28 continues the processing from step S16.

  Thereby, pixels having different motion vector directions are removed as noise. Further, the connection block corresponds to the moving body. When specifying a connected block, if the number of pixels constituting the connected block is smaller than a predetermined threshold, it can be removed as noise.

  The CPU 28 determines whether or not a request to end the motion vector calculation process has been received (S20). If the process has not ended (NO in S20), the process from step S10 is continued. When the process is finished (YES in S20), the CPU 28 finishes the process.

  FIG. 7 is a flowchart showing a moving object determination processing procedure of the moving object determination device 2. The CPU 28 searches for the motion vector of the pixels in the connected block (S30). The CPU 28 calculates an average value in the searched motion vector direction (S31). The CPU 28 specifies the calculated average value as the movement direction of the connected block (S32), and calculates the angle difference between the specified movement direction and a predetermined approach direction (S33). In this case, the approach direction refers to a direction in which a moving body moving on the roads A and B approaches the intersection E (that is, the moving body determination device 2).

  The CPU 28 determines whether or not the calculated angle difference is equal to or smaller than the second threshold value (S34). When the calculated angle difference is equal to or smaller than the second threshold (YES in S34), the CPU 28 generates display information (S35), and synthesizes the generated display information with the captured image (S36). Accordingly, when it is determined that there is a moving body on the captured image that moves in the approaching direction, display information for highlighting the moving body is attached. As display information for highlighting, for example, a moving body on a captured image is surrounded by a rectangular frame, the frame is blinked (for example, every 0.5 seconds), and the color of the frame is changed at a predetermined cycle. The frame size can be changed at a predetermined cycle.

  The CPU 28 determines whether or not processing has been performed for all connected blocks in one frame (S37), and when processing of all connected blocks has been completed (YES in S37), the CPU 28 performs imaging that combines display information. The image is output (S38), and the process is terminated. If all connected blocks have not been processed (NO in S37), the processing after step S30 is continued. On the other hand, when the calculated angle difference is not equal to or smaller than the second threshold value (NO in S34), the CPU 28 continues the process from step S37.

  The above-described processing is processing for one frame of the captured image, but this processing can be continued for each frame. Further, the processing may be performed by thinning out each time a plurality of frames are used.

  FIG. 8 is an explanatory diagram showing an example of a connected block. As shown in the figure, the captured image is divided by predetermined pixels, the motion vector of each pixel is calculated, and the calculated motion vector angular difference is equal to or less than the first threshold value, and only adjacent pixels are connected. By doing so, the connected block is specified. Even if the angular difference of the motion vectors is a pixel that is equal to or smaller than the first threshold, the separated pixels are removed as noise. Further, even when the number of connected pixels is equal to or less than a predetermined threshold, the moving object can be accurately determined by the connected block by removing it as noise. Note that moving bodies such as vehicles, two-wheeled vehicles, and pedestrians can be distinguished based on the size or shape of the identified connecting block.

  FIG. 9 is an explanatory diagram illustrating an example of a moving object specified by a connection block. As described above, the video camera 1 is arranged so as to capture the roads A and B that intersect the intersection E. The moving body of the captured image at a certain imaging time point is specified by the connected block.

FIG. 10 is an explanatory diagram showing calculation information calculated by the mobile body determination device 2. As shown in FIG. 10 (a), 1 frame of the captured image, for example, the pixel P _1, P ₂ of 480 × 640, is divided into ... P _n. As shown in FIG. 10B, motion vectors PV ₁ , PV ₂ ,... PV _n calculated for each pixel are recorded. The motion vector of pixels for which no motion has been detected is zero. As shown in FIG. 10C, the approaching moving body (for example, approaching vehicles V1, V2,...) Among the determined moving bodies is recorded for each captured image of one frame.

  FIG. 11 is an explanatory diagram illustrating an example of a captured image in which display information is combined. As shown in the figure, the moving body determination device 2 travels, for example, in a range of about 50 m from the intersection E of roads A and B, which are blind spots from the driver or passenger of the vehicle traveling from the road C toward the intersection E. A captured image with a rectangular frame attached to the moving body that moves in the direction approaching the intersection E is output. The in-vehicle device that has received the captured image via the wireless transmission device 3 displays the image on a display device mounted on the vehicle.

  As a result, the driver or passenger of the vehicle can more easily and reliably determine the presence of the moving body approaching from the blind spot of the intersection toward the intersection. In particular, by using a motion vector detection technique, even a low-contrast moving object can be accurately determined on a road with low visibility such as a blind spot at an intersection or a curve with poor visibility. In addition, the moving body determination system according to the present invention is a device that receives and displays a captured image without deteriorating the safety of a driver or a passenger of a vehicle that does not include a device that receives and displays the captured image. Accident avoidance information can be provided to the driver or the passenger of the vehicle equipped with the vehicle, so that safety can be surely improved as a whole society.

  In the above-described embodiment, the roads A, B, C, and D intersect the intersection E. However, the road form at the intersection is not limited to this, such as a T-shaped road. The present invention can also be applied to a place where there is a corner that becomes a blind spot for a vehicle traveling on one road.

Embodiment 2
In the first embodiment described above, when calculating a motion vector, the final motion vector is calculated by combining the motion vectors calculated by the block matching method and the gradient method. However, the present invention is not limited to this. For example, the block matching method and the gradient method can be properly used according to the distance to the moving body.

  FIG. 12 is an explanatory diagram illustrating an example in which a captured image is divided and a motion vector calculation method is selectively used. As shown in the figure, when the distance to the moving body is long, that is, in the right and left regions on the captured image, the motion vector is calculated by the gradient method. On the other hand, when the distance to the moving body is short, that is, in the central region on the captured image, the motion vector is calculated by the block matching method.

  When the moving body is at a distance from the intersection, the magnitude of the motion vector is relatively small, and the gradient method that can calculate a minute motion vector of less than one pixel is excellent. On the other hand, when the moving body is at a short distance, the motion vector changes greatly, so that a block matching method that can efficiently calculate a large motion vector is excellent. Note that the motion vector calculation procedure in the block matching method and the gradient method is the same as that in the first embodiment, and a description thereof will be omitted.

Embodiment 3
In the above-described embodiment, the pixel block for calculating the motion vector (in the case of the block matching method) or the local region (in the case of the gradient method) has a horizontally long rectangular shape. For example, the size can be changed according to the distance to the moving body.

  FIG. 13 is an explanatory diagram illustrating an example of a pixel block or a local region. As shown in the figure, when the distance to the moving body is long, that is, in the right and left regions on the captured image, the horizontally long pixel block or the local region is reduced (for example, 4 × 8). On the other hand, when the distance to the moving body is short, that is, in the central region on the captured image, the horizontally long pixel block or the local region is enlarged (for example, 8 × 16).

  Depending on the distance to the moving body, the size of the moving body on the captured image also differs, and the size of the pixel block or the local area is set to 1 / of the size of the moving body (for example, a vehicle, a motorcycle, a pedestrian). By making the size about 2 to 1/10, unnecessary information on the road surface other than the moving object is excluded, and the motion vector is accurately obtained while reducing the processing effort for motion vector calculation. Can be calculated.

Embodiment 4
In the above-described embodiment, the video camera is installed in the vicinity of the intersection and the moving object approaching the intersection with the blind spot is determined. However, the installation location of the video camera is not limited to this, For example, the present invention can also be applied to a case where a moving body approaching a curve with poor visibility is determined.

  FIG. 14 is a schematic diagram illustrating an outline of the moving object determination system according to the fourth embodiment. In the figure, the mobile body determination system includes a video camera 1, a mobile body determination device 2, a wireless transmission device 3, and the like. The video camera 1 is installed approximately in the middle of a curve with poor visibility, and images a region including a road. As shown in the figure, it is assumed that the curve has, for example, the installation location of the video camera 1 in the center and roads F and G are connected to both sides thereof. The optical axis of the video camera 1 images, for example, a moving body (vehicle, two-wheeled vehicle, pedestrian, etc.) existing in a range of about 50 m (moving body determination range) from the installation location of the video camera 1 on the roads F and G. It is arranged along the road direction.

  A moving body determination device 2 is connected to the video camera 1. The moving body determination device 2 processes a captured image obtained by capturing with the video camera 1 to determine the presence of the moving body, and outputs a captured image in which the determined moving body is highlighted. A wireless transmission device 3 is connected to the moving body determination device 2. The wireless transmission device 3 has a directivity in two directions in the transmission direction of radio waves. For example, information can be transmitted from the wireless transmission device 3 to a vehicle in the range of about 50 m on the road F. In addition, information can be transmitted from the wireless transmission device 3 to a vehicle in the range of about 50 m on the road G, and in which direction radio waves are transmitted can be switched.

  In the storage unit 26 of the mobile body determination device 2, the approach direction for specifying the direction in which the mobile body approaches (to the mobile body determination device 2) on the captured image and the transmission direction of the radio wave of the wireless transmission device 3 are stored. It is stored in correspondence. For example, when the CPU 28 determines that the moving body is approaching from the road G, the CPU 28 determines that the road direction that can collide with the moving body is the direction approaching from the road F, and emphasizes only the moving body. The wireless transmission device 3 is controlled so that the display information to be displayed is combined with the captured image and the combined captured image is transmitted in the direction of the road F. When the CPU 28 determines that the moving body is approaching from the road F, the CPU 28 determines that the road direction that can collide with the moving body is the direction approaching from the road G, and emphasizes only the moving body. The wireless transmission device 3 is controlled so that the display information to be displayed is combined with the captured image and the combined captured image is transmitted in the direction of the road G. Since other parts are the same as those in the first to third embodiments, description thereof is omitted.

  The in-vehicle device that has received the captured image combined with the display information for highlighting the moving object that is approaching via the wireless transmission device 3 displays it on the display device mounted on the vehicle. As a result, the driver or passenger of the vehicle can more easily and reliably determine the presence of the moving body approaching from the front of the curve with poor visibility than before, and can prevent a collision accident.

Embodiment 5
In the above-described fourth embodiment, the radio transmission device having directivity in the radio wave transmission direction is used. However, the present invention is not limited to this. For example, the radio transmission device is installed on a road away from the video camera. The present invention can also be applied to installation.

  FIG. 15 is a schematic diagram illustrating an outline of the moving object determination system according to the fifth embodiment. In the figure, the mobile body determination system includes a video camera 1, a mobile body determination device 2, wireless transmission devices 3a and 3b, and the like. The video camera 1 is installed approximately in the middle of a curve with poor visibility, and images a region including a road. As shown in the figure, it is assumed that the curve has, for example, the installation location of the video camera 1 in the center and roads F and G are connected to both sides thereof. The optical axis of the video camera 1 images, for example, a moving body (vehicle, two-wheeled vehicle, pedestrian, etc.) existing in a range of about 50 m (moving body determination range) from the installation location of the video camera 1 on the roads F and G. It is arranged along the road direction.

  A moving body determination device 2 is connected to the video camera 1. The moving body determination device 2 processes a captured image obtained by capturing with the video camera 1 to determine the presence of the moving body, and outputs a captured image in which the determined moving body is highlighted. Radio transmitters 3 a and 3 b are connected to the mobile body determination device 2 through the communication line 5. Note that the mobile body determination device 2 and the wireless start devices 3a and 3b are not limited to wired connections and may be connected wirelessly. As shown in FIG. 15, each of the wireless transmission devices 3 a and 3 b can transmit information to a vehicle traveling in the area indicated by the oblique lines of the roads F and G. As the wireless transmission devices 3a and 3b, for example, an optical beacon, a radio beacon, or the like can be used.

  The storage unit 26 of the mobile body determination device 2 associates the approach direction for specifying the direction in which the mobile body is approaching (to the mobile body determination device 2) on the captured image with the wireless transmission devices 3a and 3b. I remember it. For example, when the CPU 28 determines that the moving body is approaching from the road G, the CPU 28 determines that the road direction that can collide with the moving body is the direction approaching from the road F, and emphasizes only the moving body. The display information to be displayed is combined with the captured image, and the combined captured image is controlled to be transmitted from the wireless transmission device 3a to the in-vehicle device of the vehicle traveling on the road F. When the CPU 28 determines that the moving body is approaching from the road F, the CPU 28 determines that the road direction that can collide with the moving body is the direction approaching from the road G, and emphasizes only the moving body. The display information to be displayed is combined with the captured image, and the combined captured image is controlled to be transmitted from the wireless transmission device 3b to the in-vehicle device of the vehicle traveling on the road G. Since other parts are the same as those in the first to fourth embodiments, description thereof is omitted.

  The in-vehicle device that has received the captured image combined with the display information for highlighting the moving body that approaches is displayed on the display device mounted on the vehicle via the wireless transmission devices 3a and 3b. As a result, the driver or passenger of the vehicle can more easily and reliably determine the presence of the moving body approaching from the front of the curve with poor visibility than before, and can prevent a collision accident. It should be noted that the configuration of the above-described fifth embodiment can be similarly configured on a road that intersects an intersection.

  In Embodiment 5 described above, one wireless transmission device 3a, 3b is installed on a curve with poor visibility with the video camera 1 in between, but this is not a limitation, and the wireless transmission device 3a is not limited to this. Depending on the communicable distance between 3b and the in-vehicle device, a plurality of units can be installed with a required separation distance along the curve. As a result, it is possible to recognize a moving body that runs opposite to the vehicle sufficiently before a curve with poor visibility.

Embodiment 6
In Embodiments 1 to 5 described above, the lens used for the video camera is a standard lens or a wide-angle lens. However, the present invention is not limited to this, and the presence of a moving object is determined in a wider range. For this purpose, a fish-eye lens (super wide-angle lens) can be used. When a fisheye lens is used, the captured image is distorted. Therefore, it is necessary to correct the captured image before calculating the motion vector.

  FIG. 16 is an explanatory diagram illustrating an example of converting a captured image captured by a fisheye lens into a corrected image. It is assumed that the image of the point P on the real space (X, Y, Z) passes through the center of the fisheye lens at the input angle θ and is projected onto the point q (u, v) on the imaging surface (center is assumed to be o). If the projection point in the case of using a standard lens is q ′ (u ′, v ′), F: q (u, v) → q ′ (u ′, v ′) is the conversion formula to the corrected image. Assuming that the focal length of the fisheye lens is f, when the fisheye lens is an equidistant projection method, the equation r = f · θ is established. In the case of a standard lens, since the input angle and the output angle are equal, the equation r ′ = f · tan θ is also established. q (u, v) and q ′ (u ′, v ′) are expressed by Equations (11) and (12) of Formula 8. Accordingly, θ is expressed by Expression (13) of Expression 8, and the conversion coefficient a is expressed by Expression (14) of Expression 8. Since the above result and q are on the straight line iq ′, the fisheye lens image can be converted to the corrected image by u ′ = a · u and v ′ = a · v.

  FIG. 17 is an explanatory diagram illustrating an example of a captured image obtained by combining display information when a fisheye lens is used. A fisheye lens is installed in the vicinity of the intersection, about 50 m is imaged from the vicinity of the intersection of the four roads intersecting the intersection, and the fisheye lens image obtained by imaging is converted into a corrected image. Thereby, the picked-up image which looked at the intersection vicinity can be obtained. The mobile body determination device 2 outputs, for example, a captured image with a rectangular frame attached to a mobile body that approaches from one road toward an intersection. Moreover, the mobile body determination apparatus 2 outputs a captured image without attaching a rectangular frame to a mobile body that moves in a direction away from the intersection on another road. As a result, the driver or passenger of the vehicle can more easily and reliably determine the presence of the moving body approaching from the blind spot of the intersection toward the intersection, and can prevent a collision accident. .

  In the above example, the video camera provided with the fisheye lens is installed near the intersection. However, the present invention is not limited to this, and the video camera can be installed on a curve with poor visibility. As a result, the driver or passenger of the vehicle can more easily and reliably determine the presence of the moving body approaching from the front of the curve with poor visibility than before, and can prevent a collision accident.

Embodiment 7
In the first to sixth embodiments described above, the motion vector of each pixel block is calculated from the captured image obtained by capturing with the video camera. However, the present invention is not limited to this. Imaging, MPEG, MPEG2, MPEG4, H.264. The motion vector information of each pixel block included in the video data converted into the encoded video format such as H.264 may be used. For example, a motion vector is calculated in advance on the basis of captured images obtained by imaging with video cameras 1, 1,... Installed near a plurality of intersections and in a curve with poor visibility, and the calculated motion vector is communicated. Even if there are intersections with blind spots or poorly-sighted curves at remote points or at many points obtained by a mobile unit determination device connected to the line, the mobile units at those points Existence can be determined intensively.

  FIG. 18 is a schematic diagram showing an outline of a moving object determination system according to Embodiment 7 of the present invention. In the figure, reference numeral 1 denotes a video camera that captures an area including a road. The video camera 1 is installed in the vicinity of a plurality of intersections or in a curve with poor visibility, and the optical axis of the video camera 1 is, for example, about 50 m from a road in the range of 50 m from the vicinity of the intersection or a position where the video camera is installed. It is arranged along the road direction so as to image moving bodies (vehicles, two-wheeled vehicles, pedestrians, etc.) existing in the curve of the range.

  A control device 6 is connected to the video camera 1, and a wireless transmission device 3 is connected to the control device 6. The control device 6 encodes image data obtained by imaging with the video camera 1 based on a predetermined method (for example, MPEG, MPEG2, MPEG4, H.264, etc.) and calculates based on the image data. The motion vector thus encoded is encoded, and the encoded data and motion vector are transmitted to the mobile object determination device 2 connected via the communication line 7.

  Here, MPEG, MPEG2, MPEG4, H.264. An encoded video such as H.264 compresses video data by detecting and storing only moving parts in an image. When converting to this format, a pixel motion vector is calculated. Is done.

  As will be described later, the control device 6 combines the captured image output from the mobile object determination device 2 via the communication line 7 (when the presence of the mobile object is determined, display information that highlights the mobile object is synthesized. The captured image) is transmitted to the in-vehicle device of the vehicle through the wireless transmission device 3. As a result, even if there are intersections with blind spots or curves with poor visibility at remote locations, or even at many locations, the presence of moving objects at those locations is determined intensively, and a collision accident occurs. Can be prevented.

  The moving body determination device 2 acquires the encoded data transmitted from the control devices 6, 6,... By the communication unit 25 instead of the image input unit 21, and restores the acquired image data of the original data. At the same time, motion vectors and the like are extracted. The moving body determination device 2 identifies a connected block based on the extracted motion vector, determines the presence of the moving body, and if the moving direction of the moving body is a predetermined approach direction, the moving body is determined. The highlighted captured image is output to each of the control devices 6, 6,... Via the communication line 7.

  FIG. 19 is a block diagram showing the configuration of the control device 6. The video camera 1 outputs a captured image obtained by imaging to the image input unit 61 as a video signal (analog signal). The image input unit 61 outputs the acquired video signal to the A / D conversion unit 62, and the A / D conversion unit 62 converts the input video signal into a digital signal, which is converted under the control of the CPU 68. The obtained digital signal is stored in the image memory 63 as image data. The CPU 68 uses the captured image input from the video camera 1 via the image input unit 61 as image data in synchronization with the frame rate of the video camera 1 (interval at the time of imaging, for example, 30 frames per second). The image data is stored in the image memory 63 in units of frames (for example, 480 × 640 pixels).

  The CPU 68 encodes the image data stored in the image memory 63 based on a predetermined method (for example, MPEG, MPEG2, MPEG4, H.264, etc.), and the encoded data is transferred from the communication unit 65 to the mobile unit. It transmits to the determination apparatus 2. The CPU 68 calculates a motion vector based on the image data when performing the encoding process, and encodes the calculated motion vector.

  The auxiliary storage unit 67 reads the computer program PG, and the CPU 68 loads the read computer program into the RAM 64 and executes the loaded computer program PG to perform motion vector calculation processing and the like. Since the motion vector calculation process is the same as that in the first embodiment, description thereof is omitted.

  FIG. 20 is a flowchart illustrating a processing procedure of the moving object determination device 2 according to the seventh embodiment. The CPU 28 receives the encoded image data transmitted from the control device 6 (S50). The CPU 28 extracts a motion vector from the received encoded image data (S51).

  The CPU 28 specifies pixels that are substantially the same in the direction of the calculated motion vector and that connect adjacent pixels (S52). The CPU 28 searches for a motion vector of the pixels in the connected block (S53). The CPU 28 calculates the average value of the searched motion vector directions (S54). The CPU 28 specifies the calculated average value as the moving direction of the connected block (S55), and calculates the angle difference between the specified moving direction and a predetermined approaching direction (S56).

  The CPU 28 determines whether or not the calculated angle difference is equal to or smaller than the second threshold (S57). When the calculated angle difference is equal to or smaller than the second threshold (YES in S57), the CPU 28 generates display information (S58), and synthesizes the generated display information with the captured image (S59). Accordingly, when it is determined that there is a moving body on the captured image that moves in the approaching direction, display information for highlighting the moving body is attached. Display information for highlighting includes, for example, surrounding a moving object on a captured image with a rectangular frame, blinking the frame, changing the color of the frame at a predetermined cycle, and changing the size of the frame to a predetermined size. It can be changed with the period.

  The CPU 28 determines whether or not processing has been performed for all connected blocks in one frame (S60), and when processing for all connected blocks is completed (YES in S60), the CPU 28 performs imaging by combining display information. The image is output to the control device 6 (S61), and the process ends. If all connected blocks have not been processed (NO in S60), the processing after step S53 is continued. On the other hand, when the calculated angle difference is not equal to or smaller than the second threshold value (NO in S57), the CPU 28 continues the processing from step S60.

  The above-described processing is processing for one frame of the captured image, but this processing can be continued for each frame. Further, the processing may be performed by thinning out each time a plurality of frames are used. This makes it possible to stably determine the presence of a moving body approaching from a road that is a blind spot of an intersection or a curve with poor visibility in a wide range and at multiple points and remote points.

  In the above-described first to third embodiments, the presence of a moving body approaching from the roads A and B crossing the intersection E is determined, and a captured image highlighting the moving body is transmitted to a vehicle traveling on the road C. Although it was a structure, it is not limited to this, The mobile body which approaches by providing one more radio transmitter 3 with directivity, or providing two radio transmitters 3 with directivity It is also possible to transmit a captured image in which is highlighted to a vehicle traveling on the road D. Furthermore, the presence of a moving body approaching from the roads C and D can also be determined by providing the video camera 1 and the like for imaging the roads C and D.

  In the above-described embodiment, an infrared video camera can be used to safely avoid a night collision.

  In Embodiments 1 to 6 described above, the video camera 1 and the moving body determination device 2 are configured as separate devices. However, the video camera 1 and the moving body determination device 2 are integrated into one unit. You may comprise as an apparatus.

  In the above-described embodiment, the motion vector is calculated for all the pixels of the captured image. However, the motion vector may be calculated for each block including a plurality of pixels.

  In the embodiment described above, when the motion vector is calculated by the block matching method, the correlation value expressed by the equation 1 is used. Any method such as a sum of absolute values of difference gradation values of pixels, an absolute value of difference of average gradation values of pixels, or an absolute value of difference of standard deviation of gradation values of pixels may be used.

  In the above-described embodiment, when acquiring captured images at different imaging time points, the time interval at the imaging time point can be set as appropriate according to the traffic situation of the road. The time interval can be shortened for roads on which the mobile body travels at a relatively high speed, and the time interval can be lengthened for roads with many low-speed traveling vehicles.

  In the above-described embodiment, the captured image highlighting the approaching moving body is displayed on the display device mounted on the vehicle. However, the present invention is not limited to this, and HUD (Head Up display) The captured image can also be displayed on a windshield or the like.

It is a schematic diagram which shows the outline | summary of the mobile body determination system which concerns on this invention. It is a block diagram which shows the structure of a moving body determination apparatus. It is explanatory drawing which shows an example of a captured image. It is explanatory drawing which shows the motion vector of a pixel. It is explanatory drawing which shows the example of calculation of the motion vector of a mobile body determination apparatus. It is a flowchart which shows the process sequence of the motion vector calculation of a moving body determination apparatus. It is a flowchart which shows the process sequence of the mobile body determination of a mobile body determination apparatus. It is explanatory drawing which shows the example of a connection block. It is explanatory drawing which shows the example of the mobile body specified by the connection block. It is explanatory drawing which shows the calculation information calculated with a moving body determination apparatus. It is explanatory drawing which shows the example of the captured image with which the display information was synthesize | combined. It is explanatory drawing which shows the example in the case of dividing a picked-up image and using a motion vector calculation method properly. It is explanatory drawing which shows the example of a pixel block or a local area | region. It is a schematic diagram which shows the outline | summary of the mobile body determination system of Embodiment 4. FIG. 10 is a schematic diagram illustrating an outline of a moving object determination system according to a fifth embodiment. It is explanatory drawing which shows the example which converts the picked-up image imaged with the fisheye lens into a correction image. It is explanatory drawing which shows the example of the captured image with which the display information at the time of using a fisheye lens was synthesize | combined. It is a schematic diagram which shows the outline | summary of the moving body determination system which concerns on Embodiment 7 of this invention. It is a block diagram which shows the structure of a control apparatus. 18 is a flowchart illustrating a processing procedure of a moving object determination device according to Embodiment 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video camera 2 Moving body determination apparatus 3, 3a, 3b Wireless transmission apparatus 4 Convex mirror 5 Communication line 6 Control apparatus 7 Communication line 21, 61 Image input part 22, 62 A / D conversion part 23, 63 Image memory 24, 64 RAM
25, 65 Communication unit 26, 66 Storage unit 27, 67 Auxiliary storage unit 28, 68 CPU
29 CD-ROM

Claims (11)

In a moving body determination system comprising: an imaging device that captures an area including a road; and a mobile body determination device that determines the presence of a mobile body based on a captured image obtained by capturing with the imaging device.
The mobile body determination device is
A specifying means for specifying a connected block formed by connecting pixels whose motion vector angle difference between captured images is equal to or less than a first threshold;
Means for determining the presence of a moving object based on the identified connected block;
Generating means for generating display information for highlighting the determined moving body;
An output means for combining the generated display information with a captured image and outputting it. Storage means for storing an approach direction on a captured image corresponding to a direction in which a moving body approaches the imaging device;
Calculating means for calculating an angle difference between the direction of the motion vector of the connected block and the approach direction;
The generating means includes
The moving body determination system according to claim 1, wherein display information is generated when the angle difference calculated by the calculation means is equal to or smaller than a second threshold value. Transmission means having directivity in the transmission direction;
Determination means for determining a direction on a road that can collide with a moving body that moves in a direction approaching the imaging device, and
The transmission means includes
The moving body determination system according to claim 2, wherein the captured image obtained by combining the display information is transmitted to an in-vehicle device that moves in the direction determined by the determination unit. A transmission means installed on one road,
Determination means for determining a direction on a road that can collide with a moving body that moves in a direction approaching the imaging device, and
The transmission means includes
The moving body determination system according to claim 2, wherein a captured image obtained by combining display information is transmitted to an in-vehicle device that moves on the one road in the direction determined by the determination unit. Based on a block matching method using a pixel block in each of the captured images at the first imaging time point and the second imaging time point at which the image capturing time points are different, the first motion vector of the pixel of the captured image at the first image capturing time point is calculated. Means for calculating;
A local area is obtained in each of the new captured image obtained by moving the pixel of the captured image at the first imaging time point and the captured image at the second imaging time point according to the first motion vector calculated by the means. Means for calculating a second motion vector of a pixel of the new captured image based on a gradient method using
The moving body determination system according to any one of claims 1 to 4, wherein a combined vector of the first and second motion vectors calculated by both means is used as a motion vector of a pixel of a captured image.   6. The moving object determination system according to claim 5, wherein the size of the pixel block or the local region is larger in a region corresponding to a short distance of the captured image than in a region corresponding to a long distance of the captured image. Means for calculating a motion vector of a pixel in a region corresponding to a long distance of the captured image based on a gradient method using a local region in each of a plurality of captured images at different imaging points;
A unit that calculates a motion vector of a pixel in a region corresponding to a short distance of the captured image based on a block matching method using a pixel block in each of a plurality of captured images at different imaging points;
The moving body determination system according to any one of claims 1 to 4, wherein the motion vector calculated by both means is used as a motion vector of a pixel of a captured image.   The moving object determination system according to claim 5, wherein the pixel block or the local region has a horizontally long rectangular shape.   The moving body determination system according to any one of claims 1 to 4, further comprising means for acquiring a motion vector of a pixel of a captured image. In the moving body determination method for determining the presence of a moving body based on a captured image obtained by imaging,
Specify a connected block formed by connecting pixels whose angle difference between the motion vectors of the captured image pixels is equal to or less than the first threshold,
Based on the identified connected block, determine the presence of the moving body,
Generate display information to highlight the determined moving object,
A moving body determination method comprising: combining generated display information with a captured image and outputting the synthesized image. In a computer program for causing a computer to determine the presence of a moving object based on a captured image obtained by imaging,
Computer
Means for calculating an angular difference of motion vectors of pixels of a captured image;
Means for determining whether the angle difference calculated by the means is equal to or less than a first threshold;
Means for specifying a connected block formed by connecting pixels whose angle difference is equal to or less than a threshold;
Means for determining the presence of a moving object based on the identified connected block;
Means for generating display information for highlighting the determined moving body;
A computer program that functions as means for combining generated display information with a captured image.

Images