JP2010076492A - Vehicular imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular imaging apparatus capable of suppressing an excessive increase in exposure after a wiper appears on an image. <P>SOLUTION: A vehicular imaging apparatus 10 includes a camera controller 12. The camera controller 12 controls exposure of a camera 11 depending on a brightness value of an imaged frame image. The camera controller 12 acquires operation information of a wiper 2, and suppresses an AUTO exposure control when the wiper 2 appears on the frame image based on the acquired operation information of the wiper 2. Consequently, an increase in exposure when the wiper 2 appears on the frame image in the vehicular imaging apparatus 10 is suppressed and therefore an excessive increase in exposure after the wiper 2 appears on the frame image is suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device for a vehicle used in a vehicle such as an automobile.

As a conventional vehicle imaging device, for example, the one described in Patent Document 1 is known. In this vehicle imaging device, the front of the vehicle is imaged by a camera (imaging device) mounted on the vehicle. Then, the exposure amount of the camera is obtained based on the brightness value of the captured image by the exposure amount control means, and the exposure amount is controlled.
JP 2008-54170 A

  Here, in the above-described vehicular imaging apparatus, there is the following fear. That is, for example, as shown in FIG. 4, when the wiper 2 is actuated and appears in the image 31, the brightness value of the image 31 decreases, so that the exposure amount control means controls the exposure amount to increase. At this time, for example, the exposure amount remains large even after the reflection of the wiper 2 due to the influence of a control delay (delay) or the like, and the exposure amount may be excessive.

  Therefore, an object of the present invention is to provide a vehicle imaging apparatus that can suppress an excessive exposure amount after a wiper is reflected in an image.

  In order to solve the above problems, an imaging apparatus for a vehicle according to the present invention includes an exposure amount control unit that controls an exposure amount of an imaging apparatus according to a luminance value of a captured image, and information acquisition that acquires operation information of a wiper. And exposure amount control suppression means for suppressing control by the exposure amount control means when the wiper is reflected in the image based on the wiper operation information acquired by the information acquisition means. .

  According to this vehicle imaging device, since an increase in the exposure amount when the wiper is reflected in the image is suppressed, it is possible to suppress the exposure amount from being excessive after the wiper is reflected. As a result, an image having no problem in the exposure state can be acquired even after the wiper is reflected.

  Further, it is preferable that the exposure amount control suppressing unit suppresses the control by the exposure amount control unit to be canceled when the wiper is reflected in the image. In this case, the exposure amount when the wiper is reflected in the image is consequently equal to the exposure amount when the wiper is not reflected. Therefore, it is possible to suitably suppress an increase in the exposure amount when the wiper is reflected in the image.

  Further, it is preferable that the exposure amount control suppressing unit controls the exposure amount so that the exposure amount when the wiper is reflected in the image becomes the exposure amount when the wiper is not reflected in the image. Thereby, the increase in the exposure amount when the wiper is reflected in the image can be suitably suppressed.

  Specifically, when the wiper is reflected in the image, the exposure amount control suppressing unit may set the exposure amount to a constant value and deactivate the exposure amount control unit.

  Further, the image processing apparatus further comprises image position estimating means for estimating the image position of the wiper when the wiper is reflected in the image based on the wiper operation information acquired by the information acquiring means, and the exposure amount control suppressing means It is preferable to change the calculation area for calculating the luminance value of the amount control means according to the image position of the wiper estimated by the image position estimation means. In this case, since the image area not including the wiper is used as the calculation area, it is possible to reduce an adverse effect on the luminance value due to the wiper appearing in the image, and the exposure amount when the wiper is reflected in the image. Can be suppressed.

  According to the present invention, it is possible to prevent the exposure amount from becoming excessive after the wiper is reflected in the image. As a result, an image having no problem in the exposure state can be acquired even after the wiper is reflected.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

[First Embodiment]
First, a first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram showing a vehicular imaging apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the vehicle imaging device 10 of the present embodiment is mounted on a vehicle 1 such as an automobile, and includes a camera (imaging device) 11, a camera control device 12, and an image processing device 13.

  The camera 11 images the surroundings (here, the front) of the vehicle 1 and outputs a frame image (image) for each predetermined imaging cycle to the camera control device 12 as an image signal. This frame image has a frame number provided in the order of imaging.

  The camera control device 12 is for controlling the exposure amount of the camera 11 and taking an image. Specifically, the camera control device 12 automatically controls the exposure amount (exposure value) in the camera 11 according to the luminance value (brightness per unit region value) of the frame image input from the camera 11 ( Hereinafter, it is referred to as “AUTO exposure control”. Further, the camera control device 12 outputs the frame image input from the camera 11 to the image processing device 13. The image processing device 13 performs image processing on the frame image input from the camera control device 12.

  Here, the camera control device 12 is connected to a wiper control device 3 that controls the operation of the wiper 2. The wiper control device 3 outputs to the camera control device 12 an operation start signal related to whether or not the wiper 2 has started operation and an operation signal related to wiper operation information such as the operation speed of the wiper 2.

  Further, the camera control device 12 is configured to display the wiper 2 in the frame image based on the input wiper operation information, that is, when the wiper 2 or its shadow appears in the frame image (the wiper 2 crosses the front of the camera 11). The AUTO exposure control is suppressed (details will be described later).

  Next, the process of the vehicle imaging device 10 will be described with reference to FIGS. 2 is a flowchart showing a processing procedure of the vehicle imaging device 10 in FIG. 1, FIG. 3 is a diagram showing a frame image by the vehicle imaging device 10 in FIG. 1, and FIG. 4 is a frame image by the conventional vehicle imaging device. FIG. 3 and 4, the frame image 21 is time-sequential in the order of (a) to (e), and the other vehicle 5 is reflected in the frame image 21.

  In the vehicle imaging device 10 of the present embodiment, when the operation of the wiper 2 is started (when the operation start signal is input to the camera control device 12: Yes in S1), the camera control device 12 performs the following operation. Processing is executed.

  First, based on the operation speed of the wiper 2 in the wiper operation information, the frame number of the frame image 22 (see FIG. 3), which is the frame image 21 in which the wiper 2 is reflected, is calculated (S2). Then, when the calculated frame number matches the frame number of the current frame image 21, the wiper 2 is detected in the frame image 21 assuming that it is the timing when the wiper 2 is reflected in the frame image 21 (S2).

  Here, when the wiper 2 is reflected in the frame image 21, the luminance value of the frame image 21 decreases due to the influence of the wiper 2. Therefore, when the wiper 2 is detected in the frame image 21, the exposure time is extended so that the AUTO exposure control is activated and the exposure amount is increased.

  On the other hand, in this embodiment, when the wiper 2 is detected in the frame image 21, the AUTO exposure control is suppressed to be canceled (cancelled), and the currently set exposure time of the camera 11 is short (under). (S3). Specifically, the control value is determined and controlled so as to shorten the exposure time based on the exposure time table stored in advance and associated with the frame number. That is, when the wiper 2 is reflected in the frame image 21, the camera control means 12 of the present embodiment reduces the exposure amount increased by the AUTO exposure control accordingly. In S3, the control value may be determined and controlled so that the exposure time is shortened based on the luminance value of the entire frame image 21.

  Thus, in the present embodiment, since AUTO exposure control is suppressed when the wiper 2 is reflected, the exposure amount is excessive in the frame image 32 (see FIG. 4) after the wiper 2 is reflected as in the prior art. Can be suppressed. As a result, the frame image 22 having no problem in the exposure state is captured and acquired by the camera 11 even after the wiper 2 is reflected.

  Subsequently, the frame image 21 captured by the camera 11 is output to the image processing device 13 and image processing is executed (S4). Then, the number of elapsed frames is incremented by the camera control device 12 (S5), and the process proceeds to S3 until the number of elapsed frames becomes larger than a predetermined frame number that is a preset number of frames (S6). → S3).

  On the other hand, when the wiper 2 is not operating (when the operation start signal is not input to the camera control device 12: No in S1), when the wiper 2 is not reflected in the frame image 21 (No in S2). The frame image 21 captured by the camera 11 is output to the image processing device 13 as it is, and image processing is executed (S7). Then, when the number of elapsed frames is larger than the specified number of frames (Yes in S6) and after S7, the processes of S1 to S7 are repeatedly executed until imaging is completed (S8).

  As described above, according to the vehicle imaging device 10 of the present embodiment, since the increase in the exposure amount when the wiper 2 is reflected in the frame image 21 is suppressed, the exposure amount becomes excessive after the wiper 2 is reflected. It becomes possible to suppress. As a result, it is possible to obtain the frame image 21 having no problem in the exposure state even after the wiper 2 is reflected.

  In other words, the vehicle imaging device 10 can be suitably used in subsequent image processing by suppressing (shifting so as to cancel) luminance value deviations between the plurality of frame images 21 acquired during the operation of the wiper 2. It is possible to suppress an increase in the number of frame images 21, that is, an increase in the number of frame images 32 (see FIG. 4) that are too bright to be used.

  In the present embodiment, as described above, when the wiper 2 is reflected in the frame image 21, the AUTO exposure control is suppressed to cancel. Therefore, the exposure amount when the wiper 2 is reflected in the frame image 21 is eventually equal to the exposure amount when the wiper 2 is not reflected, and it is preferable to increase the exposure amount when the wiper is reflected in the frame image 21. Can be suppressed.

  In the above, the camera control device 12 that executes the AUTO exposure control constitutes the exposure amount control means. The camera control device 12 that acquires the operation information of the wiper 2 constitutes information acquisition means. Based on the operation information of the wiper 2, the camera control device 12 that suppresses the AUTO exposure control constitutes an exposure amount control suppressing means.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the description of the present embodiment, differences from the first embodiment will be mainly described.

  The camera control device 12 of the present embodiment estimates the image position of the wiper 2 when the wiper 2 is reflected in the frame image 21 based on the input wiper operation information. Then, as shown in FIG. 5, when the wiper 2 is reflected in the frame image 21, a photometric area (calculation area) 25 for calculating a luminance value by AUTO exposure control (hereinafter referred to as “photometric”) is estimated. The wiper 2 is changed according to the image position of the wiper 2.

  As shown in FIG. 5A, in the normal frame image 21 in which the wiper 2 is not reflected, the entire image is a photometric area 25a. Further, as shown in FIG. 5B, in the frame image 22 when the wiper 2 is reflected on the right side of the image, the ½ left area which is the left half of the frame image 22 is changed to the photometric area 25b. Further, as shown in FIG. 5C, in the frame image 22 when the wiper 2 is reflected on the left side of the image, the ½ right area which is the right half of the frame image 22 is changed to the photometric area 25c.

  In the camera control device 12, the following processing is executed. That is, when the wiper 2 is detected in the frame image 21 (Yes in S2 of FIG. 6), the image position of the wiper 2 is estimated (S11). Then, according to the image position of the wiper 2, the processing area for photometry is changed from the photometry area 25a to the photometry areas 25b and 25c (S12).

  The photometric area 25 to be changed may be determined based on an exposure time table stored in advance and associated with the frame number, or may be determined from the luminance distribution of the immediately preceding frame image 21.

  As described above, according to the vehicular imaging apparatus of the present embodiment, the area of the frame image 21 that does not include the wiper 2 is selected as the photometric area 25, and thus the luminance value when the wiper 2 is reflected in the frame image 21. The adverse effect on can be reduced. As a result, an increase in the exposure amount when the wiper 2 is reflected in the frame image 21 can be suppressed, and the frame image 22 having no problem in the exposure state can be acquired even after the wiper 2 is reflected.

  In the above, the camera control device 12 that estimates the image position of the wiper 2 when the wiper 2 is reflected in the frame image 21 based on the operation information of the wiper 2 constitutes an image position estimation unit.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the description of the present embodiment, differences from the first embodiment will be mainly described.

  The camera control device 12 of the present embodiment controls the exposure amount so that when the wiper 2 is reflected in the frame image 21, the exposure amount is obtained when the wiper 2 is not reflected in the frame image 21. Specifically, when the wiper 2 appears in the frame image 21, the camera control device 12 switches from AUTO exposure control to manual exposure control that manually controls the exposure amount of the camera 11. The shutter speed is fixed to a constant value when the wiper 2 is not reflected.

  In the camera control device 12, the following processing is executed. First, a manual exposure control section that is a section for switching from AUTO exposure control to manual exposure control is set. Here, a change history of the shutter speed at the time of AUTO exposure control is recorded, and a manual exposure control section is set based on this change history.

  FIG. 7 is a graph showing a change history of the shutter speed of the camera 11. In the figure, the horizontal axis indicates the number of frames, and the vertical axis indicates the shutter speed per frame of the camera 11. FIG. 7A shows the shutter speed when only the AUTO exposure control is operated, and FIG. 7B shows the shutter speed when the AUTO exposure control and the manual exposure control are operated.

  As shown in FIG. 7A, in the section A in which the wiper 2 is reflected in the frame image 21, the AUTO exposure control is activated and the shutter speed is increased. Even after the passage of section A, the shutter speed changes. Therefore, in this embodiment, a section after the passage of section A and until the change in shutter speed settles is set as the manual exposure control section B. The manual exposure control section B is periodically changed, for example, every time the wiper operates 100 times.

  Subsequently, when the number of frames is within the manual exposure control section B, the control of the exposure amount of the camera 11 is switched from the AUTO exposure control to the manual exposure control. The shutter speed in this manual exposure control is set to be fixed to the shutter speed in the frame image 21 immediately before the manual exposure control section B, as shown in FIG.

  As described above, according to the vehicle imaging device of the present embodiment, the exposure amount when the wiper 2 is reflected in the frame image 21 is equal to the exposure amount when the wiper 2 is not reflected. An increase in the amount of exposure when the image is reflected can be suitably suppressed.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the camera 11 is used as the imaging device, but various imaging devices other than the camera 11 may be used.

  In the above embodiment, the camera control device 12 uses a signal output from the wiper control device 3. However, a separate sensor for detecting the operation information of the wiper 2 is provided and a signal output from the sensor is used. May be used.

  Moreover, in the said embodiment, although the camera 11 makes object the vehicle front, in order to cope with retreat (back | bag) of the vehicle 1, you may make object the vehicle back, and may make object the vehicle side.

1 is a schematic configuration diagram illustrating a vehicle imaging device according to a first embodiment of the present invention. It is a flowchart which shows the process sequence of the imaging device for vehicles of FIG. It is a figure which shows the frame image by the imaging device for vehicles of FIG. It is a figure which shows the frame image by the conventional imaging device for vehicles. It is a figure which shows the frame image by the imaging device for vehicles concerning 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the imaging device for vehicles which concerns on 2nd Embodiment of this invention. It is a graph which shows the change history of the shutter speed of the camera in the imaging device for vehicles concerning a 3rd embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Wiper, 10 ... Imaging device for vehicles, 11 ... Camera (imaging device), 12 ... Camera control device (exposure amount control means, information acquisition means, exposure amount control suppression means, image position estimation means), 21, 22 ... Frame image (image), 25, 25a, 25b, 25c .. Photometric area (calculation area).

Claims (5)

Exposure amount control means for controlling the exposure amount of the imaging device in accordance with the luminance value of the captured image;
Information acquisition means for acquiring operation information of the wiper;
Exposure amount control suppression means for suppressing control by the exposure amount control means when the wiper is reflected in the image based on the wiper operation information acquired by the information acquisition means. An imaging apparatus for a vehicle.   2. The vehicular imaging apparatus according to claim 1, wherein the exposure amount control suppression unit suppresses the control by the exposure amount control unit to be canceled when the wiper is reflected in the image.   2. The exposure amount control suppressing unit controls the exposure amount so that the exposure amount when the wiper is reflected in the image is equal to the exposure amount when the wiper is not reflected in the image. Vehicle imaging device.   4. The vehicle imaging according to claim 3, wherein when the wiper is reflected in the image, the exposure amount control suppressing unit sets the exposure amount to a constant value and deactivates the exposure amount control unit. apparatus. Further comprising image position estimating means for estimating an image position of the wiper when the wiper is reflected in the image based on the operation information of the wiper acquired by the information acquiring means;
When the wiper is reflected in the image, the exposure amount control suppressing unit is configured to calculate a calculation region for calculating the luminance value of the exposure amount control unit in the image by the image position estimating unit. The vehicular imaging device according to claim 1, wherein the vehicular imaging device is changed according to the image position of the vehicle.

Images