JP2010271143A - Imaging device, distance measuring device, exterior monitoring device, and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive imaging device for imaging a plurality of optical images and preferably an inexpensive imaging device for distance measurement having a combination of two sets of stereo cameras. <P>SOLUTION: The imaging device includes an imaging sensor 13 having an imaging surface divided into a plurality of imaging regions and an optical filter 14 that separates a plurality of image information by light beams with which the imaging surface is irradiated from any of different directions and preferably image information irradiated from a lens 12 of a short-distance photographing camera and a lens 11 of a long-distance photographing camera into each image information to form the information in the individual imaging regions of the imaging surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging device, a distance measuring device, a vehicle exterior monitoring device, and an imaging method.

  Install a TV camera in the car to monitor the front of the vehicle, recognize the distance to the person in front of the vehicle, other vehicles, obstacles, etc., and if there is a risk of colliding with them, notify the driver, 2. Description of the Related Art An ASV (Advanced Safety Vehicle) device that operates a vehicle brake to stop or decelerate is known.

  What is indispensable in the ASV apparatus is an object distance measuring apparatus in front of the vehicle. A distance measuring device that measures a distance from an object in front of a vehicle using a television camera or the like is already known. Such a distance measuring device generally has a pair of cameras, called stereo cameras, placed on a vehicle at an interval, and the same object is photographed by both cameras. This is a distance measurement method that applies the so-called triangulation principle to calculate the distance from the object.

  In such a vehicle-mounted distance measuring apparatus using a stereo camera, it is necessary to be able to measure a distance from a short-distance obstacle near the vehicle to a relatively long-distance obstacle such as a forward vehicle traveling at high speed. On the other hand, in order to improve the distance measurement accuracy for long-distance obstacles by triangulation using a stereo camera, it is necessary to extend the baseline length, which is the length between the two cameras, or to increase the focal length of the camera. . When the base line length is increased, the distance between the cameras is increased, the stereo camera device is likely to be enlarged, and there is a limit as a vehicle-mounted distance measuring device. On the other hand, when the focal length of the camera is increased, the measurement accuracy of an obstacle at a short distance decreases due to the characteristics of the lens. Further, when the focal length is increased, the viewing angle of the camera is narrowed, so that the field of view that can be measured is narrowed. For obstacles in the vicinity of the vehicle, it is necessary to be able to recognize the vehicle diagonally in front of the vehicle. For short-distance obstacles, a wide viewing angle of the camera is required.

  In order to solve this problem, a distance measuring device using two sets of stereo cameras having different focal lengths is known (in the present application, a camera combining two sets of stereo cameras is also referred to as a twin stereo camera). . For example, the distance measurement range of a normal in-vehicle twin stereo camera is about 20m to 100m in the case of a long-distance shooting camera, and about 5m to 30m in front of the vehicle in the case of a short-distance shooting camera. is there. That is, with a stereo camera for long-distance shooting, it is possible to monitor an object 20 m or more away, but the accuracy of distance measurement cannot be maintained for objects closer to it. For this reason, there is no problem when traveling on a highway at a relatively high speed, but an object in the vicinity of the vehicle cannot be monitored, and it is often not useful when traveling at a low speed. Further, as a feature of the long-distance shooting camera, it is not possible to use a wide-angle camera in order to shoot a high-precision image at a long distance, and monitoring in front of the vehicle near the side of the vehicle becomes insufficient. On the other hand, with a stereo camera for short-distance shooting, it is possible to monitor an object in the vicinity of the vehicle and it is easy to make a wide-angle camera. However, the accuracy of distance measurement cannot be maintained for an object farther than 30 m.

  For this reason, a twin stereo camera for distance monitoring actually mounted on a vehicle is often a stereo camera system that combines a stereo camera for long-distance shooting and a stereo camera for short-distance shooting. When traveling at high speeds, the distance to a relatively far obstacle is monitored by a stereo camera for long-distance shooting. When traveling at a low speed, the distance from the obstacles ahead of the vehicle by a stereo camera for short-distance shooting is monitored. To monitor. Two sets of stereo cameras, ie, a long-distance shooting stereo camera and a short-distance shooting stereo camera, are switched artificially or automatically in accordance with the traveling state.

  Patent Document 1 proposes an out-of-vehicle monitoring apparatus equipped with a twin stereo camera system capable of always performing distance measurement over a wide range from a long distance to a short distance in the above-described twin stereo camera system. This out-of-vehicle monitoring device measures the distance of an object in each image information with two sets of stereo cameras for long-distance shooting and stereo camera for short-distance shooting, and the distance that can be measured by both stereo cameras. By collating the object in the image processing technology and adopting only one image, the object from the short distance of about 5 m to the long distance of about 100 m is put in one image information, and the short distance Enables distance measurement from to a long distance.

  This eliminates the need to determine the switching time, which has been a problem in the conventional technology in which two pairs of near and near stereo cameras are switched according to the situation. In addition, while driving at a high speed during operation of the stereo camera for long-distance shooting, which was a problem in the prior art, the other vehicle immediately outside the detection range of the stereo camera for long-distance shooting immediately before the own vehicle Even in the case where the vehicle is interrupted, it is possible to detect the interrupting vehicle and immediately connect to the warning operation or the danger avoidance operation.

  As described above, it has become relatively easy to measure and monitor the distance of an obstacle or the like in front of a running vehicle with a vehicle outside monitoring apparatus using two sets of far and near stereo camera systems. However, conventional out-of-vehicle monitoring devices have required two sets of stereo cameras, a long-distance stereo camera and a short-distance stereo camera, that is, a camera system that combines at least four cameras. For this reason, the camera system was complicated and expensive. In particular, in a twin stereo camera system for distance measurement, optical image information is converted into electronic image information by an image sensor (CCD or the like), and the electronic image information is computer processed to measure distance. It is necessary to have at least four image sensors that convert the image data into electronic image information. In addition, the imaging surface of the imaging element is an aggregate of a large number of pixels, and it is necessary to increase the number of pixels in order to improve measurement accuracy. The increase in the number of pixels of the image sensor has an effect on aspects other than the cost of the twin stereo camera system for distance measurement, such as an increase in the size of the imaging screen and an increase in the amount of electronic information processing corresponding to the number of pixels. As described above, an imaging apparatus that simultaneously captures a plurality of optical images, such as a twin stereo camera system, is likely to be expensive and large-scale.

  In view of the above problems, an object of the present invention is to provide an inexpensive imaging device that can capture a plurality of optical images, a distance measuring device including the imaging device, a vehicle outside monitoring device, and a plurality of optical images at a low cost. It is to provide an imaging method.

  An imaging apparatus according to the present invention includes an imaging element that converts optical information into electronic information, and an optical filter that forms image information using light rays on an imaging surface of the imaging element. The imaging device uses the imaging surface divided into a plurality of imaging regions, and an optical filter is disposed in front of the imaging surface, and this optical filter is a light beam that is emitted toward the imaging surface from different directions. A plurality of pieces of image information are separately formed in each of the divided imaging regions on the imaging surface.

  With reference to FIG. 1, separation of a plurality of pieces of image information irradiated from different directions by an optical filter will be described. In FIG. 1, an optical filter 14 is disposed in front of an imaging surface having two imaging regions 13a and 13b (on the side on which optical information is irradiated). Then, light beams including two pieces of image information, that is, image information formed by the lens 11 of the long-distance shooting camera and image information formed by the lens 12 of the short-distance shooting camera are in different directions (in FIG. 1). Is irradiated on the imaging surface 13 via the optical filter 14 from the upper left and lower left). A part of the optical filter 14 (the central part in FIG. 1) includes a light shielding unit 15 that blocks part of the light emitted from the lens 11 and the lens 12 toward the imaging surface 13. With the optical filter 14 having such a structure, as shown in FIG. 1, the light emitted from the lens 11 of the long-distance photographing camera obliquely downward and forward does not irradiate the imaging region 13a, but only the imaging region 13b. Irradiate. On the other hand, the light emitted from the lens 12 of the short-distance photographing camera obliquely upward and forward does not irradiate the imaging region 13b, but irradiates only the imaging region 13a. In this way, two pieces of image information by the light beams emitted from the two directions of the diagonally lower front and the diagonally upper front are separated by the optical filter 14, and the imaging area 13 a in the imaging surface 13 disposed after the optical filter 14, Images are formed separately on 13b.

  In the description of FIG. 1, the imaging surface 13 is composed of two imaging regions 13a and 13b, and the two pieces of image information are separated on the respective imaging regions 13a and 13b, but the imaging surface 13 is composed of a large number of imaging regions, The two pieces of image information are each divided into a plurality of image areas, and it is preferable that the plurality of image areas on the imaging surface 13 are irradiated for each of the divided image areas. Each imaging area on the imaging surface 13 may correspond to the divided image area.

  The image information divided into a plurality of image areas and irradiated to each of the plurality of imaging areas on the imaging surface 13 is converted into electronic information by the imaging element, and the image information of the plurality of image areas converted into the electronic information is The short-distance image information of the short-distance photographing camera and the long-distance photographing camera, which are re-combining processing by an image combination processing device (not shown) and separated into two electronic information states, respectively. It becomes long-distance image information. A computer equipped with an image processing program may be used as the image combination processing device.

  In the example shown in FIG. 1, the light shielding unit 15 is an image of a light shielding plate that blocks light. However, the light shielding unit 15 does not necessarily absorb or reflect light, and is incident on the light shielding unit 15. It is only necessary to change the direction of a part of the light so as not to reach a predetermined imaging area on the imaging surface 13. Such a light shielding member may be a lens, a prism, a diffraction grating, or the like. That is, the optical filter according to the present invention is preferably any one of a lenticular lens, a microlens array, a lattice-shaped light shielding plate, or a light shielding member having translucency only in a predetermined direction.

  A distance measuring device according to the present invention includes a stereo camera system including a pair of short-distance shooting stereo cameras and a pair of long-distance shooting stereo cameras. Normally, a stereo camera for short-distance shooting is provided with a wide-angle lens, and a stereo camera for long-distance shooting is relatively provided with a telephoto lens. This distance measurement device further includes a distance information acquisition device, which acquires stereo image information captured by the respective stereo cameras as electronic information and integrates the respective stereo image information. One integrated stereo image information can be obtained. Further, the distance information acquisition device can calculate and acquire distance information of an object existing from a short distance to a long distance in the integrated stereo image information.

  In the distance measuring device according to the present invention, the combination of at least one imaging device in a stereo camera for short-distance shooting and at least one imaging device in a stereo camera for long-distance shooting is the above-described imaging device according to the present invention. Is included. That is, at least one imaging device in the short-distance shooting stereo camera and at least one imaging device in the long-distance shooting stereo camera are shared by one imaging device. The irradiation light from the lens of the stereo camera for short-distance shooting and the irradiation light from the lens of the stereo camera for long-distance shooting irradiate the imaging surface of the shared imaging device from different directions. is doing. Furthermore, each irradiation light irradiates the imaging surface through the optical filter provided in the imaging apparatus according to the present invention. For this reason, the irradiation light from the lens of the stereo camera for short-distance shooting and the irradiation light from the lens of the stereo camera for long-distance shooting are separated by an optical filter and irradiated to separate imaging areas on the imaging surface, respectively. ing.

  In the distance measuring device according to the present invention, the lens of the stereo camera for short-distance shooting and the lens of the stereo camera for long-distance shooting that irradiate the shared imaging device with optical information are arranged close to each other. The arrangement of the lenses is preferably arranged so as to be perpendicular to the arrangement of the pair of lenses (base line of the stereo camera) in the short-distance shooting stereo camera. In this stereo camera system, it is preferable that the arrangement of the pair of lenses in the stereo camera for short-distance shooting and the arrangement of the pair of lenses in the stereo camera for long-distance shooting are parallel to each other. These are preferably arranged in the lateral direction (horizontal direction).

  The vehicle exterior monitoring device of the present invention includes the above-described distance measuring device of the present invention mounted on a vehicle, and acquires an object in an image captured by a stereo camera system including both a stereo camera and the distance measuring device. A risk determination device that determines the risk during driving is provided on the basis of the distance information.

  Moreover, it is preferable that the vehicle exterior monitoring device of the present invention includes a notification device that notifies danger or a risk avoidance device that avoids danger based on the information of the risk determination device. Examples of the notification device include an audible alarm device such as an alarm buzzer and warning sound, and a visual alarm device such as an alarm lamp and warning character display. Examples of the danger avoidance device include a vehicle speed control device, an automatic brake device, an automatic horn warning device, and an automatic hazard lamp lighting device.

  In the imaging method of the present invention, a light irradiation process for irradiating a plurality of image information by light on an imaging surface from different directions and a plurality of image information by irradiated light are separated by an optical filter, and each image information An optical image separation step of forming an image on separate imaging regions of the imaging surface, and an imaging step of imaging each separated image information with an imaging element having an imaging surface having a plurality of imaging regions, and converting each image information to electronic information Including.

  According to the present invention, an inexpensive imaging device that captures a plurality of optical images, a distance measuring device including the imaging device, a vehicle exterior monitoring device, and an imaging method that captures a plurality of optical images at a low cost are provided. Can do.

It is principle explanatory drawing which separates the optical image information irradiated to an imaging surface from two directions with an optical filter, and makes each optical image information. 1 is a schematic diagram of an imaging apparatus according to Embodiment 1 of the present invention. It is a schematic diagram of the imaging device which concerns on Embodiment 2 of this invention. It is a schematic diagram of the imaging device which concerns on Embodiment 3 of this invention. It is an image figure of the conversion process from the optical image information separated and divided | segmented and displayed on the imaging area of the imaging surface in the imaging device which concerns on this invention to the combined electronic image information. It is an illustration figure of the scenery outside a vehicle (vehicle front). It is the image of the scenery outside a vehicle image | photographed with the camera for short distance photography. It is the image of the scenery outside a vehicle image | photographed with the camera for long distance photography. It is an arrangement plan of each lens of a twin stereo camera system in a distance measuring device concerning Embodiment 6 of the present invention. It is an arrangement plan of each lens of a twin stereo camera system in a distance measuring device concerning Embodiment 7 of the present invention. It is an arrangement plan of each lens of a twin stereo camera system in a distance measuring device concerning Embodiment 8 of the present invention.

  The present invention will be described by way of example embodiments. The following embodiment is an example of the present invention, and the present invention may be modified or changed without departing from the spirit of the present invention, and is described in the embodiment. It may not be.

(Embodiment 1)
An imaging apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view for explaining the imaging apparatus according to the first embodiment. In FIG. 2, an optical filter 14 is disposed in front of the imaging surface 13 (on the light irradiation side) with an interval. The imaging surface 13 is composed of a plurality of imaging areas 13a, 13b, 13c and the like. The imaging regions 13a, 13b, 13c, and the like may be individual pixels in an imaging element such as a CCD element, but in the present embodiment are an aggregate of a plurality of pixels in the imaging element. The pixels in each imaging region are connected to an imaging signal processing device, an imaging signal storage device, and the like including an image combination processing device (not shown).

  The optical filter 14 is made of a plate-like light transmitting body such as glass or plastic, and a plurality of light shielding portions 15a and 15b are provided on both surfaces thereof. The light shielding part 15a on the front side (side not facing the imaging surface 13) and the light shielding part 15b on the rear side (side facing the imaging surface 13) have the same shape and the same arrangement interval. As shown in FIG. 2, the arrangement of the light shielding portions 15a and the light shielding portions 15b is shifted by a predetermined length in the horizontal direction. In the first embodiment, the light-shielding portions 15a and 15b are extended in the same shape in the depth direction in FIG. That is, the light shielding portions 15a and 15b each form a striped pattern parallel to the depth direction of the drawing.

  Here, as shown in FIG. 2, a part of light (optical image information) indicated by a straight line irradiated obliquely from the upper right is partially blocked by the optical filter 14 and partially transmitted. The transmitted light beam forms a striped pattern on the imaging surface 13. If the widths of the imaging regions 13a, 13b, and 13c and the distance between the imaging surface 13 and the optical filter 14 are appropriately set, the light rays indicated by straight lines are alternately captured from the imaging region 13b on the imaging surface 13. An image is formed only on the top. On the other hand, a part of light rays (light image information) indicated by a dotted line irradiated from the upper left side are partially blocked by the optical filter 14 and partially transmitted. The transmitted light beam forms a striped pattern on the imaging surface 13. Light rays (optical image information) indicated by dotted lines form an image only on every other imaging area from the imaging area 13 a on the imaging surface 13. In this manner, the light beam (optical image information) indicated by a straight line and the light beam (optical image information) indicated by a dotted line are separated and divided and formed on the imaging surface 13.

  Two pieces of optical image information formed separately on the imaging surface 13 are converted into electronic information for each pixel such as the imaging regions 13a, 13b, and 13c, and the imaging signal processing device and the imaging signal are used as image information as electronic information. Sent to a storage device.

  The imaging apparatus according to the present embodiment uses two very simple optical filters to separate two pieces of optical image information into separate imaging areas on the imaging surface of one imaging element, and each image information is divided into a plurality of pieces. Images can be formed by dividing into regions. For this reason, the imaging apparatus of this embodiment has few manufacturing parts, is inexpensive, is easy to assemble, and has few failures. As will be described in detail later, the imaging apparatus of the present embodiment forms two pieces of image information on one imaging plane and converts them into electronic information. Since the image is separated or divided only in one direction, the fineness of the pixels in the respective image information in the separation and non-division directions is different from the image information formed on one imaging surface. Absent.

(Embodiment 2)
The imaging device according to the second embodiment is similar to the imaging device according to the first embodiment, but the structure of the optical filter 14 is different. As shown in the schematic cross-sectional view of FIG. 3, the optical filter 14 according to the second embodiment is an optical filter element in which a light shielding member parallel to the light beam of irradiation light including image information is disposed inside a transparent medium such as glass or plastic. 14a, 14b. In FIG. 3, two optical filter elements 14a and 14b that are parallel to two light beams irradiated from different directions are shown. Usually, however, there are many combinations of optical filter elements 14a and 14b in FIG. It is connected in the left-right direction.

  Also in this case, if the distance between the optical filter element 14 and the imaging surface 13 is set to a predetermined length, the light beam that has passed through the optical filter element 14a (dotted light beam in FIG. 3) passes through the imaging region 13a on the imaging surface 13. The light beam that has been irradiated and transmitted through the optical filter element 14 b (solid light beam in FIG. 3) irradiates the imaging region 13 b on the imaging surface 13. The dotted light beam does not irradiate the imaging region 13 b on the imaging surface 13, and the solid light beam does not irradiate the imaging region 13 a on the imaging surface 13. If there are a plurality of such combinations of the optical filter element 14 and the imaging surface 13 in the horizontal direction in FIG. 3, the light image by the solid line light beam and the light image by the dotted light beam in FIG. Formed on the surface 13. If the structure of the optical filter element 14 and the imaging surface 13 shown in FIG. 3 is directly connected to the depth direction of the paper surface of FIG. 3, the optical image information formed on the imaging surface 13 is separated from the two optical image information. And are alternately formed in a striped pattern.

  Since the optical image information on the imaging surface 13 in the present embodiment is the same as the optical image information on the imaging surface 13 in the first embodiment, description after the conversion from optical image information to electronic information is omitted. Note that one of the features in the present embodiment is that the optical filter 14 can efficiently block light emitted from a direction other than a predetermined direction, and noise light is not easily irradiated on the imaging surface 13.

(Embodiment 3)
FIG. 4 shows an imaging apparatus according to Embodiment 3 of the present invention. FIG. 4 is a cross-sectional view for explaining an image pickup apparatus in which an optical filter 14 made of a lenticular lens and an image pickup surface 13 made of a plurality of image pickup regions are combined. In FIG. 4, the left figure is a sectional view of a lenticular lens, and the right figure is an explanatory sectional view in which one lenticular lens separates and irradiates two image information on the imaging regions 13 a and 13 b on the imaging surface 13. .

  The lenticular lens 14c in the present embodiment collects light irradiated from different directions at different positions. If it demonstrates according to FIG. 4, the light irradiated from diagonally upper right will be condensed by the lenticular lens which is the optical filter element 14c, and will form an image in the imaging area 13b on the imaging surface 13. FIG. The light irradiated obliquely from the upper left is condensed by the same lenticular lens (optical filter element) 14 c and forms an image in the imaging region 13 a on the imaging surface 13. In this embodiment, two imaging regions 13a and 13b correspond to one lenticular lens that is the optical filter 14c. A plurality of combinations of the single lenticular lens and the imaging regions 13a and 13b are connected in the horizontal direction in FIG. 4, and two pieces of optical image information are imaged corresponding to the imaging regions 13a and 13b on the imaging surface 13, respectively. An image is formed by being divided and divided into regions. The computerization of optical images formed in the imaging region 13a and the imaging region 13b and the subsequent processing are the same as in the first and second embodiments.

  The difference between the present embodiment and the first and second embodiments is that all the light irradiated to the optical filter 14 is used by being refracted and there is no light that is shielded and wasted. For this reason, the optical image formed on the imaging surface 13 is bright and clear. Conversely, the imaging apparatus of this embodiment can recognize light image information with a small amount of light as sufficiently bright and clear image information.

(Embodiment 4)
The optical filter element 14c in FIG. 4 may be a microlens instead of a lenticular lens, and the optical filter element 14 may be a microlens array. In this case, the optical filter element 14 has a plurality of microlenses arranged in the depth direction of the paper surface of FIG. As in the third embodiment, the imaging surface 13 includes imaging regions 13a and 13b that are elongated in the depth direction of the drawing. The imaging apparatus shown in FIG. 4 that is regarded as described above is an imaging apparatus according to the fourth embodiment. The imaging apparatus according to the fourth embodiment has the same effects as those described for the imaging apparatus according to the third embodiment. However, in the imaging apparatus according to the fourth embodiment, the arrangement direction of the optical filter 14 is further specified. There is an advantage in assembling the equipment that there is no need to

  In the imaging devices according to the first to third embodiments, the optical filter 14 is parallel to the imaging surface 13, the longitudinal direction of the light shielding portions 15 a and 15 b or the longitudinal direction of the lenticular lens element, and the imaging region 13 a on the imaging surface 13. , 13b etc. had to be aligned with the longitudinal direction. However, in the present embodiment, as long as the optical filter 14 is parallel to the imaging surface 13, the optical filter 14 can be freely arranged with respect to the arrangement direction of the imaging regions 13a and 13b on the imaging surface 13.

(Processing of optical image information formed separately on the imaging surface)
Until now, the optical image information formed separately on the imaging surface has been mainly described based on the image information in a state of being separated into two imaging regions. However, it is preferable that each separated image information is divided into a plurality of partial image information at the same time as being separated and formed in an imaging region on the imaging surface. Then, partial image information formed in these divided imaging regions is converted into electronic information by the imaging element and combined as respective image information.

  With reference to FIG. 5, a description will be given of optical image information formed by being separated and divided on the imaging surface, and a process of combining the respective image information. The left diagram in FIG. 5 is an image diagram of the entire imaging surface in which the separated and divided optical image information is formed on the imaging surface. The upper right diagram and the lower right diagram in FIG. 5 are image diagrams in which only the imaging region of one image information is extracted and combined from the entire imaging surface of the left diagram.

  If it demonstrates according to FIG. 5, the left figure of FIG. 5 represents the whole imaging surface 13, and this imaging surface 13 is divided | segmented into the 10 strip-shaped horizontal imaging area labeled imaging area 131-140. . Then, as described in the first to fourth embodiments, each of the two pieces of optical image information separated and divided by the optical filter is divided into a plurality of (5 in this example) image areas, and alternately. Are formed as optical images on the imaging regions 131-140.

  In FIG. 5, the content of one image information is A, and the content of the other image information is B. On the entire imaging surface 13, the contents of the image information A and the image information B are divided into five pieces and arranged alternately in strip-like imaging areas 131 to 140. This is converted into electronic information by an image sensor, and further subjected to image processing by an image combination processing device such as a computer, so that the imaging areas 131 to 140 are separated into an odd-numbered imaging area and an even-numbered imaging area. When the separated imaging regions are arranged in ascending order of the codes, the image information 141 and the image information 142 shown in the right diagram of FIG. 5 are obtained. In this way, the optical image information that is separated and formed on the imaging surface is separated and combined as two pieces of image information as electronic information.

  In this way, the imaging surface 13 is divided into strip-shaped imaging areas 131 to 140, allocated to the respective image information, and further set as two pieces of image information, whereby the longitudinal direction of the imaging area in each image information In FIG. 5, the number of pixels in the horizontal direction is not reduced, and fine image information can be obtained in the longitudinal direction.

(Embodiment 5)
A distance measuring device according to a fifth embodiment of the present invention will be described. The distance measuring device according to the fifth embodiment is a vehicle-mounted distance measuring device for recognizing the distance of an obstacle or the like that appears in front of a traveling vehicle. The external appearance, function, mounting position on the vehicle, and the like of this measuring device are similar to those of a conventional on-vehicle distance measuring device. That is, the distance measuring apparatus according to the fifth embodiment includes a twin stereo camera system including a pair of short-distance shooting stereo cameras and a pair of long-distance shooting stereo cameras. Furthermore, optical image information captured by each stereo camera is acquired as electronic image information, and the respective stereo image information converted into electronic information is integrated into integrated stereo image information, which is far from a short distance in the integrated stereo image information. A distance information acquisition device that acquires distance information of an object existing up to a distance is provided.

  The distance measuring device of the present embodiment includes the above-described imaging device according to the present invention, and the left and right cameras in the short-distance shooting stereo camera and the left and right cameras in the long-distance shooting stereo camera are: The left is left and the right is right, and the lenses are arranged close to each other. The left and right imaging devices corresponding to the adjacent lenses are shared by one imaging device. That is, the left cameras and the right cameras of the two sets of stereo cameras in the twin stereo camera system are each constituted by one imaging device according to the present invention. Note that the imaging apparatus according to the present invention may be a combination of only one of the left and right cameras. In the description, only one imaging apparatus is used.

  The distance measuring device according to the present embodiment includes an imaging device that has few manufacturing parts, is inexpensive, easy to assemble, and has few failures, as already described in the imaging device according to the present invention. It has the same effect as the imaging device.

  The distance measurement by the distance measurement device of the present embodiment will be described taking distance measurement of an obstacle or the like in a landscape in front of the vehicle as an example. FIG. 6 is a front view of the vehicle when the distance measuring device according to the present embodiment is mounted on the windshield of the traveling vehicle and the front of the vehicle is monitored. FIG. 7 is an image (abbreviated as a short-distance image) obtained by photographing the scenery in front of the vehicle shown in FIG. 6 with a short-distance photographing camera (one of the stereo cameras, for example, the right camera) of the distance measuring apparatus according to the present embodiment. .) Images close to the vehicle and obliquely forward of the vehicle are sufficiently focused and suitable for distance measurement. However, this image is an image that is not suitable for distance measurement because it starts to blur when it is far from the road sign at the left end of the road at a position about 30 m ahead of the vehicle. On the other hand, FIG. 8 shows an image (a long-distance image and a long-distance image) obtained by photographing the landscape in front of the vehicle shown in FIG. 6 with a long-distance photographing camera (one of the stereo cameras, for example, the right camera) of the distance measuring device of this embodiment. Abbreviated). For a position about 20 m ahead of the vehicle and far from the road sign at the left end of the road, the image is sufficiently focused and suitable for distance measurement. However, the image within 20 m ahead of the vehicle is blurred and is not suitable for distance measurement. In addition, the viewing angle of the camera is relatively narrow, and the oblique front of the vehicle cannot be photographed as much as the long-distance photographing camera.

  In the distance measuring apparatus according to the present embodiment, first, the optical image information of the short-distance image and the optical image information of the long-distance image are formed separately on one imaging surface, and then converted into electronic information for each image. Combined as information, image information based on two pieces of electronic information is acquired. Then, the short-distance image and the long-distance image based on the electronic information are integrated, for example, at a position 25 m ahead and integrated into one image information. Since each camera is fixed to the windshield of the vehicle and the focal length is also fixed, the position of the front 25 m in the image corresponds to a predetermined position on the imaging surface. In this way, clear image information suitable for measuring the distance from the vicinity of the vehicle to the distance can be obtained. Further, in the vicinity of the vehicle, clear image information is obtained with a wide viewing angle.

  Other methods may be used for integrating the two images. For example, as described in Cited Document 1, since each of the short-distance image and the long-distance image has a stereo image, the shape and distance of the object in the image are recognized from each stereo image, and the perspective image Both near and near images may be integrated so that objects having the same distance and shape in both images overlap each other.

  Although the description has been given for the right camera of the stereo camera, it is possible to obtain integrated image information in the same manner for the left camera. Once the images for distance measurement by the left and right cameras are obtained, various distance information acquisition devices applying the triangulation that has been known in the past can be used to detect each obstacle in the image information using stereo images. Distance measurement is possible.

(Embodiment 6)
FIG. 9 shows a distance measuring apparatus according to Embodiment 6 of the present invention. FIG. 9 is a view of the in-vehicle distance measuring device installed on the windshield of the vehicle as viewed from the lens side of the camera. Among the long-distance photographing lenses 11a and 11b arranged horizontally on the left and right sides, and the short-distance photographing lenses 12a and 12b arranged horizontally on the left and right, the lenses 11a and 12a arranged on the left side and arranged on the right side. The lenses 11b and 12b thus arranged are arranged close to each other. In addition, the left lens 11a disposed in close proximity to the direction in which the left and right short-distance photographing lenses 12a and 12b or the long-distance photographing lenses 11a and 11b are arranged, that is, the direction of the base line connecting the left and right cameras of the stereo camera. , 12a and the right lens 11b, 12b are arranged vertically. In other words, the two lenses of the stereo cameras of the perspective are arranged in the horizontal direction, and the two left lenses 11a and 12a and the two right lenses 11b and 12b are arranged almost vertically.

  By arranging the left lenses 11a and 12a and the right lenses 11b and 12b close to each other, optical image information emitted from the left lenses 11a and 12a and optical image information emitted from the right lenses 11b and 12b are obtained. Each can easily irradiate one imaging surface. Therefore, the imaging surfaces of the imaging devices corresponding to the left lenses 11a and 12a and the right lenses 11b and 12b can be easily shared.

  If the direction in which the lenses (for example, the left lenses 11a and 12a) that share the imaging surface are aligned is perpendicular to the direction of the baseline of the stereo camera (the line connecting the lenses of the two cameras), The longitudinal direction of the imaging region on the shared imaging surface is a direction perpendicular to the surface formed by the light rays of the two incident image information (see, for example, FIG. 2 and FIG. 5). And the longitudinal direction of the imaging region are parallel to each other. In this embodiment, since the baseline direction of the stereo camera is horizontal, the longitudinal direction of the small imaging region is also horizontal.

  In distance measurement using triangulation with a stereo camera, distance measurement is performed based on the distance between the two cameras (base line) of the stereo camera, so the accuracy of the horizontal image parallel to the base line (number of pixels) ) Affects the distance measurement accuracy of the object in the image. As can be seen from FIG. 5, the two images formed on the imaging surface in the present embodiment can use only half of the pixels on the imaging surface in the vertical direction, but all the pixels on the imaging surface in the horizontal direction. I use it. For this reason, in the distance measurement using the twin stereo camera in the present embodiment, the two pieces of near-far image information use all the pixels in the imaging surface for the baseline direction of the stereo camera. Since the distance measurement by the stereo camera is performed by the pixels along the base line direction, the distance measurement device of the present embodiment can maintain an accurate measurement accuracy not inferior to the distance measurement by the conventional twin stereo camera.

  In the distance measuring device of the present embodiment, since the distance of the base line of the stereo camera for long-distance shooting is the same as the distance of the base line of the stereo camera for short-distance shooting, the distance information from the image information acquired from each stereo camera The processing for measuring the distance of the object is simplified, and the image processing speed and accuracy are improved.

(Embodiment 7)
The distance measuring device according to the seventh embodiment of the present invention is a modification of the distance measuring device according to the sixth embodiment. A distance measuring apparatus according to this embodiment is shown in FIG. FIG. 10 is a view of the in-vehicle distance measuring device installed on the windshield of the vehicle as seen from the lens side of the camera, as in FIG. Among the long-distance photographing lenses 11a and 11b arranged horizontally on the left and right sides, and the short-distance photographing lenses 12a and 12b arranged horizontally on the left and right, the lenses 11a and 12a arranged on the left side and arranged on the right side. The lenses 11b and 12b thus arranged are arranged close to each other.

  The left and right short-distance photographing lenses 12a and 12b are arranged inside the left and right long-distance photographing lenses 11a and 11b, respectively. The base lines of the short-distance photographing lenses 12a and 12b overlap the base lines of the long-distance photographing lenses 11a and 11b. That is, the lenses 11a, 12a, 12b, and 11b are leveled in this order from left to right.

  In the distance measuring device according to the present embodiment, since the four lenses are aligned, it is possible to make the device inconspicuous and compact. Since the distance measuring device of the present embodiment is installed on the windshield of the vehicle, it is difficult to stand out and it is an important factor not to disturb the driver's visual field.

  Further, in the distance measuring apparatus of the present embodiment, since the base line of the long-distance shooting stereo camera is longer than the base line of the short-distance shooting stereo camera, the distance measurement of the long-distance object that tends to have a large measurement error in the distance measurement. Measurement accuracy can be improved.

(Embodiment 8)
The distance measuring device according to the eighth embodiment of the present invention is a modification of the distance measuring device according to the seventh embodiment. A distance measuring apparatus according to this embodiment is shown in FIG. FIG. 11 is a view of the in-vehicle distance measuring device installed on the windshield of the vehicle as seen from the lens side of the camera, as in FIG. Among the long-distance photographing lenses 11a and 11b arranged horizontally on the left and right sides, and the short-distance photographing lenses 12a and 12b arranged horizontally on the left and right, the lenses 11a and 12a arranged on the left side and arranged on the right side. The lenses 11b and 12b are arranged close to each other.

  The left and right long-distance photographing lenses 11a and 11b and the left and right short-distance photographing lenses 12a and 12b are arranged horizontally from left to right in the order of the lenses 11a, 12a, 11b, and 12b.

  In the distance measuring apparatus according to the present embodiment, the distance between the lenses of the stereo camera for long-distance shooting is the same as the distance between the lenses (baseline distance) of the stereo camera for short-distance shooting. The processing for measuring the distance of the inside object is simplified, and the image processing speed and accuracy are improved.

(Embodiment 9)
A vehicle exterior monitoring device according to the present invention will be described as a ninth embodiment. The vehicle exterior monitoring device according to the ninth embodiment includes the distance measurement device according to the present invention described in the fifth to eighth embodiments, and based on the distance information of the object in front of the vehicle acquired by the distance measurement device according to the present invention. A risk determination device that determines a risk during driving, a notification device that notifies the danger based on information of the risk determination device, and a risk avoidance device that avoids the risk are provided.

  The risk determination device sets predetermined determination criteria for the distance of obstacles ahead of the vehicle and the traveling speed of the host vehicle, and determines the risk based on this. The risk may be one kind of judgment criterion or a stepwise judgment criterion depending on the degree. The notification device that notifies the danger by the risk judgment device includes an alarm buzzer, sound, lamp, display of characters and symbols, operation of existing instruments, and the like. In addition, the notification device can notify not only the driver and passengers in the host vehicle but also the driver of other vehicles and people around the vehicle by an alarm or a warning light. The danger avoidance device is a device that controls a vehicle speed or performs a brake operation based on a risk determination result. Thereby, danger may be avoided in a shorter time than the driver.

11, 11a, 11b: Long-distance shooting camera lens 12, 12a, 12b: Short-distance shooting camera lens 13: Imaging surface 13a, 13b, 13c: Imaging region 14: Optical filters 14a, 14b, 14c: Optical filter element 15 , 15a, 15b: light shielding portions 131, 133, 135, 137, 139: imaging regions 132, 134, 136, 138, 140 divided for long-distance images on the imaging surface: divided for short-distance images on the imaging surface Imaging area 141: long-distance image 142 combining divided imaging information: short-distance image combining divided imaging information

JP-A-11-39596

Claims (11)

An imaging device having an imaging surface divided into a plurality of imaging regions;
A plurality of pieces of image information by light rays radiated to the imaging surface from different directions, separated into respective image information, and formed in separate imaging regions of the imaging surface; and
An imaging apparatus comprising:   2. The imaging according to claim 1, wherein the plurality of pieces of image information formed separately on the imaging surface are further divided into a plurality of image regions and formed in separate imaging regions on the imaging surface. apparatus.   The imaging apparatus according to claim 1, wherein the optical filter separates the plurality of pieces of image information into only one direction of the imaging surface.   The optical filter includes any one of a lenticular lens, a microlens array, a lattice-shaped light shielding plate, or a light shielding member having translucency only in a predetermined direction. The imaging device described.   The plurality of pieces of image information by light rays from different directions include image information irradiated from a lens of a short-distance shooting camera and image information irradiated from a lens of a long-distance shooting camera. Item 5. The imaging device according to any one of Items 1 to 4.   An image combination processing device that converts image information divided into the plurality of image areas into electronic information by the imaging device and combines the image information of the plurality of image areas converted into the electronic information. Item 6. The imaging device according to any one of Items 2 to 5. A pair of short-distance shooting stereo cameras, a pair of long-distance shooting stereo cameras, and stereo image information captured by each stereo camera are acquired, and the respective stereo image information is integrated and integrated stereo image information. And a distance information acquisition device that acquires distance information of an object existing from a short distance to a long distance in the integrated stereo image information,
The combination of at least one imaging device in the stereo camera for short-distance shooting and at least one imaging device in the stereo camera for long-distance shooting is the imaging device according to any one of claims 1 to 6. A distance measuring device comprising:   A lens that irradiates optical information to the imaging device that is the combination in the stereo camera for short-distance shooting and a lens that irradiates optical information to the imaging device that is the combination in the stereo camera for long-distance shooting are close to each other. And a pair of short-distance shooting stereo cameras or a pair of long-distance shooting stereo cameras arranged perpendicular to a base line of a pair of lenses. The described distance measuring device. The distance measuring device according to claim 7 or 8 mounted on an automobile,
An out-of-vehicle monitoring device for an automobile, comprising: a risk determination device that determines a risk during driving based on distance information of the object acquired by the distance measurement device.   The vehicle exterior monitoring device according to claim 9, further comprising: a notification device that notifies the danger based on information of the danger determination device, or a danger avoidance device that avoids the danger. A light irradiation process of irradiating the imaging surface with a plurality of image information by light from different directions;
An optical image separation step of separating the plurality of irradiated image information by an optical filter and forming the image information as separate image information in separate imaging regions of the imaging surface;
An imaging step of imaging each separated image information by an imaging device having an imaging surface having a plurality of imaging regions;
An imaging method comprising:

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