JP2006157634A - On-vehicle imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle imaging system for preventing a light receiver from getting dirt, the light receiver of an imaging apparatus being mounted on a vehicle. <P>SOLUTION: A rectangular transparent plate 2 is provided to a side opposed to the light receiver of a video camera 1 on a vehicle front side window within the cleaning range of a wiper for removing dirt of the vehicle front side window. The transparent plate 2 is made of zinc sulfide (ZnS) for transmitting visible light and infrared ray therethrough, and sized e.g., 50 mm×50 mm with a thickness of 5 mm. The transparent plate 2 can be manufactured by sintering processing and overheat processing, and is mounted on a position formed by cutting off a region of 50 mm square of the vehicle front side window. Thus, the transparent plate 2 can prevent the light receiver of the video camera 1 from getting dirt. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle imaging system that prevents contamination of a light receiving unit of an imaging device mounted on a vehicle.

  A video camera for infrared light is mounted on the front of a vehicle (for example, an automobile) to capture pedestrians in front of the vehicle at night and display the captured image on a display device such as a head-up display. A forward monitoring system has been proposed that alerts the person.

  The light receiving part of the video camera used in such a system uses a material that transmits far infrared light, and ordinary glass does not transmit far infrared light. It was necessary to expose the vehicle from the vehicle to the front grille.

However, when the vehicle is running, the light receiving part of the video camera may become dirty due to the flooding of the flooding from the road, rainfall, etc., and the visibility of the pedestrian may be reduced. A system has been proposed in which a sensor is attached to a video camera to warn of contamination (see Patent Document 1).
Japanese Patent Laid-Open No. 2001-211449

  However, since the system of Patent Document 1 requires a mechanism for detecting dirt, the cost of the imaging system becomes expensive, and when the light receiving unit of the video camera becomes dirty, the dirt is wiped off. There was annoyance.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and the imaging device is obtained by isolating the light receiving portion of the imaging device from the outside of the vehicle with a zinc sulfide transmission plate that transmits visible light and infrared light. It is an object of the present invention to provide an in-vehicle imaging system capable of preventing dirt from adhering to the light receiving unit.

  Another object of the present invention is that the light receiving portion is disposed opposite to the transmission plate provided in a part of the driving window, so that even if dirt is attached to the transmission plate. Another object of the present invention is to provide an in-vehicle imaging system that can easily remove dirt at a lower cost than conventional ones.

  Another object of the present invention is to provide another light receiving portion that receives infrared light and an optical element that forms an image of infrared light transmitted through each light receiving portion in a different region of the image pickup device. An object of the present invention is to provide an in-vehicle imaging system capable of recognizing a pedestrian in front of a vehicle and an occupant in the vehicle with a single imaging device.

  An in-vehicle image pickup system according to a first aspect of the present invention is an in-vehicle image pickup system that is mounted in a vehicle, includes a light receiving unit that receives infrared light, and includes an image pickup device that picks up infrared light transmitted through the light receiving unit. A transmission plate made of zinc sulfide that transmits light and infrared light is provided, and the light receiving unit is isolated from the outside of the vehicle by the transmission plate.

  In the in-vehicle imaging system according to a second aspect of the present invention, in the first aspect of the invention, the light receiving portion is disposed to face the driving window, and the transmission plate is opposed to the light receiving portion and is one of the driving windows. It is provided in the part.

  The in-vehicle imaging system according to a third aspect of the present invention is the first aspect or the second aspect, wherein the imaging device includes an imaging element, another light receiving unit that receives infrared light, and infrared light transmitted through each light receiving unit. And an optical element that forms an image on different regions of the imaging element.

  In the first invention, the light receiving portion of the imaging device is isolated from the outside of the vehicle by the zinc sulfide transmission plate. The infrared light transmitted through the transmission plate is imaged by the imaging device. Further, since the transmission plate transmits visible light, it does not block the field of view of the driver or the like outside the vehicle. Even when a flooding from the road surface or rainfall occurs when the vehicle is traveling, the dirt is blocked by the transmission plate, so that the dirt does not directly adhere to the light receiving portion of the imaging device.

  In the second invention, the light receiving unit of the imaging device is arranged to face the transmission plate provided in a part of the operation window, so that the infrared light transmitted through the transmission plate is The light is transmitted through the light receiving unit of the image pickup device and picked up by the image pickup device. Further, since the transmission plate transmits visible light, it does not block the view of the occupant to the outside of the vehicle. Even when the flooding from the road surface or rainfall occurs when the vehicle is traveling, the dirt is blocked by the transmission plate, and the dirt does not directly adhere to the light receiving portion of the imaging device. The existing wiper provided in the driving window removes the dirt even when the dirt adheres to the transmission plate provided in a part of the driving window.

  In the third invention, the infrared light for recognizing the pedestrian in front of the vehicle is transmitted by one light receiving unit of the imaging apparatus, and the transmitted infrared light is transmitted by an optical element in a predetermined region of the imaging element. Imaging infrared light. The other light receiving unit of the imaging device transmits infrared light for recognizing an occupant in the vehicle, and the transmitted infrared light is infrared light in a region different from the predetermined region of the imaging device by the optical element. Image.

  In the first invention, by separating the light receiving portion of the imaging device from the outside of the vehicle by the transmission plate, dirt adheres to the light receiving portion of the imaging device due to flooding from the road surface, rainfall, etc. when the vehicle is running. Can be prevented. Further, since the transmission plate is made of zinc sulfide that transmits visible light and infrared light, the pedestrian can be recognized without deteriorating the visibility of the occupant.

  In the second invention, the transmission plate is provided in a part of the operation window to prevent the dirt from adhering to the light receiving portion of the imaging apparatus, and the dirt is attached to the transmission plate. However, dirt can be removed without providing an additional mechanism, and the cost of the imaging system can be reduced.

  In the third aspect of the invention, by providing the optical element that forms the infrared light transmitted through the respective light receiving portions in different areas of the imaging element, the pedestrian can be recognized by one imaging apparatus and the occupant Can be recognized, and the cost of the imaging system can be reduced.

  Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is a schematic diagram showing an outline of an in-vehicle imaging system according to the present invention. In the figure, reference numeral 1 denotes a far-infrared light video camera that is mounted on a vehicle and images passengers such as pedestrians and drivers. The video camera 1 is installed at an upper center portion inside the front window of the vehicle, and is connected to an ECU 3 for pedestrian recognition via a communication line 7 for in-vehicle LAN conforming to IEEE1394.

  A rectangular transmission plate 2 is provided on the surface of the vehicle front window facing the light receiving portion of the video camera 1 and in the cleaning range of the wiper for removing dirt on the vehicle front window. The transmission plate 2 is made of zinc sulfide (ZnS) that transmits visible light and infrared light, and has a size of, for example, 50 mm × 50 mm and a thickness of 5 mm. The transmission plate 2 can be manufactured by sintering processing and overheat treatment, and is attached to a location where a 50 mm square region of the vehicle front window is cut out. Thereby, the transmission plate 2 transmits far-infrared light imaged by the video camera 1 and does not block the field of view around the vehicle with the naked eye of the driver.

  A pedestrian recognition ECU 3 is connected to a display device 4 having an operation unit, an occupant recognition ECU 6, and an airbag ECU 5 that controls the operation of the airbag via a communication line 7.

  FIG. 2 is a block diagram showing the configuration of the video camera 1. Reference numeral 11 denotes an image capturing unit. The image capturing unit 11 is a light receiving unit of the video camera 1 and includes a germanium lens 111 that transmits far-infrared light 18 from the front of the vehicle. The light receiving surface of the lens 111 is arranged in a direction perpendicular to the front direction of the vehicle, and guides the transmitted far infrared light to the mirror 113.

  The mirror 113 is arranged with an inclination angle of 45 degrees with respect to the optical axis so that the optical axis of the lens 111 is positioned at the center, and reflects the far infrared light transmitted through the lens 111. Guide to prism 114. The prism 114 has a triangular prism shape having a right isosceles triangular cross section, the optical axis of the lens 111 guided through the mirror 113 is positioned at the center of one oblique side surface, and the oblique side surface is They are arranged at an angle of 45 degrees with respect to the optical axis. A dielectric multilayer film that reflects far-infrared light is formed on the oblique side surface of the prism 114.

  A lens 112 made of germanium, which is the other light receiving portion of the video camera 1 and transmits far-infrared light 19 from an occupant in the vehicle, is disposed in the opposite direction of the mirror 113 so as to face the prism 114. is there. The optical axis of the lens 112 is matched with the optical axis of the lens 111. The light receiving surface of the lens 112 is disposed so as to face a passenger such as a vehicle driver. The prism 114 is arranged such that the optical axis of the lens 112 is positioned at the center of the other oblique side surface, and the oblique side surface forms an angle of 45 degrees with respect to the optical axis. A dielectric multilayer film that reflects far-infrared light is formed on the oblique side surface of the prism 114.

  In the apex angle direction of the prism 114, a germanium lens 115 is arranged to form images of far-infrared light reflected by each hypotenuse surface of the prism 114 in different regions of the far-infrared imaging device 116 described later. It is. The far-infrared imaging device 116 is disposed with an appropriate distance from the lens 115 so that the optical axis of the lens 115 is positioned at the center of the imaging surface.

  The far-infrared light 18 that has passed through the lens 111 that is one light receiving unit of the video camera 1 is reflected by the mirror 113 and guided to the prism 114. The far-infrared light 18 whose optical path has been changed by the prism 114 passes through the lens 115 and is imaged in a predetermined imaging region of the far-infrared imaging element 116. Further, the far-infrared light 19 transmitted through the lens 112 which is the other light receiving unit of the video camera 1 is guided to the prism 114. The far-infrared light 19 whose optical path has been changed by the prism 114 passes through the lens 115 and is imaged in an imaging area different from the area of the far-infrared imaging element 116.

  The lenses 111, 112, 115, the mirror 113, the prism 114, and the far infrared imaging element 116 are accommodated in the casing 110 of the video camera 1.

  The far-infrared imaging device 116 converts the far-infrared light 18 and 19 input for each imaging region into a luminance signal corresponding to the intensity of the far-infrared light, and outputs the luminance signal to the signal processing unit 12.

  The signal processing unit 12 performs processing for removing various distortions generated in the optical system, low-frequency noise removal processing, correction processing for correcting gamma characteristics, and the like on the luminance signal input from the image capturing unit 11. Then, the processed luminance signal is temporarily stored in the image memory 13 as image data for pedestrian recognition and image data for occupant recognition. In this case, the pedestrian area 131 and the occupant area 132 of the image memory 13 are stored separately for each imaging area.

  The interface unit 14 outputs the image data stored in the image memory 13 to the pedestrian recognition ECU 3 or the occupant recognition ECU 6 in accordance with a command transmitted from the pedestrian recognition ECU 3 or the occupant recognition ECU 6. Control, conversion of the transfer rate according to the resolution of the image captured by the video camera 1, creation of packet data from the image data, and the like. Further, the interface unit 14 outputs the pedestrian recognition image data stored in the image memory 13 to the pedestrian recognition ECU 3 under the control of the control unit 15, and the occupant recognition image data is output to the occupant recognition. It outputs to ECU6.

  The control unit 15 controls processing of the image capturing unit 11, the signal processing unit 12, and the interface unit 14 via the bus 16. For example, it interprets a command from the ECU 3 for pedestrian recognition or the ECU 6 for occupant recognition, and stores image data captured by the image capturing unit 11 in the image memory 13. The stored image data is read out and output to the pedestrian recognition ECU 3 or the occupant recognition ECU 6 via the interface unit 14.

  FIG. 3 is a block diagram showing a configuration of the ECU 3 for pedestrian recognition. In the figure, reference numeral 31 denotes an interface unit which transfers instructions to the video camera 1 and image data from the video camera 1.

  The control unit 35 stores image data for pedestrian recognition input from the video camera 1 via the interface unit 31 in the image memory 32 for each frame unit. Further, the control unit 35 outputs the image data stored in the image memory 32 to the image processing LSI 34 in units of frames.

  The image processing LSI 34 includes a pedestrian recognition unit 341 and an emphasis display providing unit 342. The pedestrian recognition unit 341 reads out image data in units of one frame from the image memory 32, and the similarity between the luminance distribution of the read image data and the standard patterns H1, H2,. Judgment of pedestrians by judging the degree.

  When the pedestrian recognition unit 341 recognizes a pedestrian, the highlighting addition unit 342 performs a highlighting process such as surrounding the recognized pedestrian with a frame, and outputs the processed image data to the output unit 33. Output to.

  The image processing LSI 34 performs the above-described processing in units of one frame, and when the processing for one frame of image data is completed, the image processing LSI 34 continues the same processing for the next frame, and outputs the processed image data to the output unit 33. Output to.

  The output unit 33 outputs the input image data to the display device 4. The control unit 35 controls operations of the interface unit 31, the image processing LSI 34, and the like.

  The display device 4 displays the highlighted pedestrian on the display along with the external environment based on the image data output from the pedestrian recognition ECU 3.

  FIG. 4 is a block diagram showing a configuration of the ECU 6 for occupant recognition. In the figure, reference numeral 61 denotes an interface unit that transfers commands to the video camera 1 and transfers image data from the video camera 1.

  The control unit 65 stores the occupant recognition image data input from the video camera 1 via the interface unit 61 in the image memory 62 for each frame. The control unit 65 outputs the image data stored in the image memory 62 to the image processing LSI 64 in units of frames.

  The image processing LSI 64 includes an occupant recognition unit 641. The occupant recognition unit 641 reads out image data in units of one frame from the image memory 62, and the similarity between the luminance distribution of the read image data and the standard patterns J1, J2,... To determine whether the occupant is leaning forward, rearward, leftward, or rightward, and outputs the determination result to an airbag ECU 5 described later via the interface unit 61. At the same time, the processed image data is output to the output unit 63.

  The image processing LSI 64 performs the above-described processing in units of one frame, and when the processing for one frame of image data is completed, the image processing LSI 64 continues the same processing for the next frame and outputs the determination result to the airbag ECU 5. In addition, the processed image data is output to the output unit 63.

  The output unit 63 outputs the input image data to the display device 4. The control unit 65 controls operations of the interface unit 61, the image processing LSI 64, and the like.

  The display device 4 displays the recognized occupant on the display based on the image data output from the occupant recognition ECU 6.

  Airbag ECU5 receives the determination result which shows the attitude | position of the passenger | crew output from ECU6 for passenger | crew recognition. When detecting an abnormal situation such as a collision of the vehicle, the airbag ECU 5 is installed in advance in a predetermined position in the vehicle so as to most reduce the impact on the occupant based on the received determination result indicating the occupant's posture. The operation order of the plurality of airbags is determined, and a control signal is transmitted to each airbag so that each airbag operates in the determined order.

  Next, the operation of the in-vehicle imaging system according to the present invention will be described. When the driver operates the operation unit provided in the display device 4 to turn on the operation switch of the video camera 1, the pedestrian recognition ECU 3 or the occupant recognition ECU 6 that receives the operation signal from the operation unit, respectively. Sends an initial command to the video camera 1 via the interface units 31 and 61.

  The video camera 1 that has received the initial command starts imaging in front of or inside the vehicle from the image capturing unit 11. The signal processing unit 12 temporarily stores the captured image data in the pedestrian area 131 or the occupant area 132 of the image memory 13, and then synchronizes each frame of image data via the interface unit 14. Then, it is sent to the ECU 3 for pedestrian recognition or the ECU 6 for occupant recognition.

  The pedestrian recognition ECU 3 temporarily stores image data for one frame in the image memory 32. The image processing LSI 34 reads the image data stored in the image memory 32, performs image processing for recognizing a pedestrian, and then outputs the processed image data to the display device 4.

  The occupant recognition ECU 6 temporarily stores image data for one frame in the image memory 62. The image processing LSI 64 reads the image data stored in the image memory 62, performs image processing for recognizing the occupant's posture, and then outputs the processed image data to the display device 4. The determination result is output to the airbag ECU 5.

  When the airbag ECU 5 detects an abnormal situation such as a collision of the vehicle, the airbag ECU 5 is configured to reduce the impact on the occupant most based on the determination result indicating the posture of the occupant received from the ECU 6 for occupant recognition. The operation order of a plurality of airbags installed in advance at a predetermined position is determined, and the operation of the airbag is controlled in the determined order.

  FIG. 5 is an explanatory diagram showing an example of an image displayed on the display device 4. As shown in the figure, the display surface is divided into two, and on the display surface D18, the far-infrared light 18 that has passed through the lens 111, which is one light-receiving unit of the video camera 1, is imaged, and image data obtained by imaging the image. The pedestrian is recognized based on the pedestrian, and the recognized pedestrian is surrounded by a rectangular highlight so as to call the driver's attention. On the display surface D19, the far-infrared light 19 that has passed through the lens 112, which is the other light-receiving unit of the video camera 1, is imaged, the posture of the occupant is recognized based on the image data obtained by the imaging, and the recognized occupant Is displayed.

  As described above, in the present invention, the video camera 1 is disposed inside the front window of the vehicle, facing the lens 111 that is the light receiving unit of the video camera 1, and visible light and By providing the zinc sulfide transmitting plate 2 that transmits infrared light, it is possible to prevent dirt from adhering to the light receiving portion of the video camera 1 due to flooding from the road surface or rainfall during traveling of the vehicle. Further, the transmission plate 2 transmits visible light and infrared light, so that even if the transmission plate 2 is provided on the front window of the vehicle, it does not hinder the driver's field of view around the vehicle. Moreover, the dirt adhering to the transmission plate 2 can be removed by an existing wiper that cleans the front window of the vehicle, and it is not necessary to provide an additional mechanism, and an inexpensive on-vehicle imaging system can be provided. In addition, by using the prism 114 that captures far-infrared light that has passed through each light-receiving unit in different imaging regions of the far-infrared imaging device 116, the front of the vehicle and the inside of the vehicle can be captured by a single video camera 1. The expensive far-infrared imaging device 116 can be shared, and an inexpensive on-vehicle imaging system can be provided.

  In the above-described embodiment, the prism 114 is used. However, the present invention is not limited to this. It is only necessary to be able to refract the optical path of far-infrared light, and a mirror is used instead of the prism 114. It may be configured to.

  In the above-described embodiment, the transmission plate 2 is provided on the front window of the vehicle. However, the location where the transmission plate 2 is mounted is not limited to this, and is provided on the vehicle rear window. Also good. Further, the transmission plate 2 can be provided at a position facing the light receiving portion of the video camera 1 according to the mounting position of the video camera 1. For example, when the video camera 1 is installed around the inside of the headlight, the transmission plate 2 can be used as a part of the headlight window.

  In the above-described embodiment, germanium is used as the material of the lenses 111, 112, and 113. However, the present invention is not limited to this, and the configuration uses chalcogen glass, zinc sulfide (ZnS), or the like. May be.

  In the above-described embodiment, as the far-infrared imaging element 116, an imaging element such as a bolometer type, pyroelectric type, thermopile type, or SOI diode can be used.

  In the above-described embodiment, the far-infrared light video camera 1 may be configured to use a near-infrared light video camera or a mid-infrared light video camera.

It is a schematic diagram which shows the outline | summary of the vehicle-mounted imaging system which concerns on this invention. It is a block diagram which shows the structure of a video camera. It is a block diagram which shows the structure of ECU for pedestrian recognition. It is a block diagram which shows the structure of ECU for passenger | crew recognition. It is explanatory drawing which shows the example of the image displayed with a display apparatus.

Explanation of symbols

1 Video camera 2 Transmission plate 3 ECU for pedestrian recognition
4 Display device 5 Airbag ECU
6 ECU for occupant recognition
111, 112, 115 Lens 113 Mirror 114 Prism 116 Far-infrared imaging device

Claims (3)

In a vehicle-mounted imaging system that is mounted in a vehicle, has a light receiving unit that receives infrared light, and includes an imaging device that images infrared light transmitted through the light receiving unit.
A zinc sulfide transmission plate that transmits visible light and infrared light is provided.
The light receiving unit is
An in-vehicle imaging system characterized by being isolated from the outside of the vehicle by the transmission plate. The light receiving unit is
It is placed opposite the driving window,
The transmission plate is
The in-vehicle imaging system according to claim 1, wherein the in-vehicle imaging system is provided in a part of the driving window so as to face the light receiving unit. The imaging device
An image sensor;
Other light receiving parts that receive infrared light,
The in-vehicle imaging system according to claim 1, further comprising: an optical element that forms an image of infrared light transmitted through each light receiving unit in different regions of the imaging element.

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