JP2009255740A - Photographing device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the visibility of an occupant and more accurately detect the occupant using a photographed image. <P>SOLUTION: The photographing device for the vehicle mounted on the vehicle is provided with light shutting-off devices 3a-3c; a camera 1; and an ECU 2. The light shutting-off devices 3a-3c are provided at a window of the vehicle, and can take a shutting-off state for shutting-off at least a part of external light transmitting through the window and a transmitting state for transmitting the external light other than the shutting-off state. The camera 1 photographs an object to be photographed in a cabin. The ECU 2 obtains brightness information regarding the object to be photographed from the photographed image by the camera 1, and controls the light shutting-off devices 3a-3c whether they are in shutting-off states or in transmitting states based on the brightness information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device for a vehicle, and more particularly to an imaging device for a vehicle for imaging a vehicle occupant (for example, a driver).

  2. Description of the Related Art Conventionally, a technique for mounting an imaging device (camera) on a vehicle and detecting the state of a vehicle occupant (for example, whether the driver is looking aside or sleeping) using an image captured by the imaging device has been considered. It has been. Here, in the vehicle interior, the image captured by the imaging device varies greatly depending on whether or not the environment is exposed to external light. Captures the imaging target correctly because the illuminance of the imaging target (occupant) changes due to external light, or the shadow (brightness) formed on the imaging target changes depending on the direction of external light. The occupant's state may not be detected correctly using the captured image.

Patent Document 1 discloses a technique for preventing the influence of external light on an imaging result obtained by an imaging apparatus. Specifically, in the photographing apparatus described in Patent Document 1, an infrared cut filter is attached to a window of a vehicle, the driver is irradiated with an infrared LED, and the driver is photographed with an infrared CCD camera. Thus, the photographing apparatus can correctly photograph the driver with the infrared CCD camera without the influence of external light.
Japanese Patent No. 3119031

  In the device described in Patent Document 1, light in a predetermined wavelength band is always shielded from outside light by an infrared cut filter attached to a vehicle window. Therefore, depending on the performance of the infrared cut filter (specifically, the degree of transmission of visible light), the visibility when the occupant looks out of the vehicle may deteriorate. In addition, when detecting the state of the occupant using the image captured by the camera, depending on the situation, it is possible to correctly detect the occupant when the external light is transmitted into the vehicle interior (as compared to the case where the external light is not transmitted). There may be cases. In this case, the apparatus described in Patent Document 1 cannot obtain a more accurate detection result.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicular imaging device capable of improving the visibility of an occupant and more accurately detecting the occupant using a captured image.

  In order to solve the above problems, the present invention employs the following configuration. That is, the first invention is a vehicle imaging device mounted on a vehicle. The vehicle imaging device includes a light shielding unit, an imaging unit, and a control unit. The light shielding unit is provided in a window of the vehicle and can take a shielding state in which at least a part of the external light transmitted through the window is shielded and a transmission state in which the external light is transmitted more than the shielding state. An imaging part images the imaging target in a vehicle interior. The control unit obtains luminance information regarding the imaging target from the image captured by the imaging unit, and controls whether the light shielding unit is in a shielding state or a transmission state based on the luminance information.

  In the second invention, the light shielding part may be provided in each of a plurality of windows of the vehicle. At this time, the control unit selects a light shielding unit to be in a shielding state among the respective light shielding units based on the luminance distribution in the image region to be imaged.

  In 3rd invention, the control part may contain the area | region selection part and the shielding selection part. The area selection unit selects a high-brightness area having a relatively high luminance and a low-brightness area having a relatively low luminance from image areas to be imaged in the captured image. The shielding selection unit selects a light shielding unit to be in a shielding state among the light shielding units based on the arrangement pattern of the high luminance region and the low luminance region.

  In the fourth invention, the control unit determines whether each of the partial areas obtained by dividing the image area to be imaged in the captured image has a luminance higher than a predetermined reference. When it is determined that the luminance is higher than a predetermined reference in all of the above, all of the light shielding portions may be in a shielding state.

  In the fifth invention, the imaging unit may be arranged to image the driver seat from the front to the rear of the driver seat of the vehicle. At this time, two of the light shielding portions are respectively provided in the windows of the right and left doors. In addition, when the left area of the image area to be imaged is higher in luminance than the right area by a predetermined reference, the control unit sets the light shielding section provided in the right door window to a shielding state, and When the brightness of the right area of the image areas is higher than a predetermined reference compared to the left area, the light shielding portion provided in the window of the left door is set in a shielding state.

  In the sixth invention, the imaging unit may be arranged to image the driver seat from the front to the rear of the driver seat of the vehicle. At this time, one of the light shielding portions is provided on the front window of the vehicle. In addition, when the lower region of the image region to be imaged has higher luminance than a predetermined reference, the control unit sets the light shielding unit provided in the front window in a shielding state.

  In the seventh invention, the light shielding part may be constituted by a liquid crystal panel.

  According to the first invention, the imaging apparatus for a vehicle includes a light shielding unit that can take a shielding state and a transmission state, and relates to an imaging target in a captured image whether the light shielding unit is in a shielding state or a transmission state. Control based on luminance information. According to this, since it is possible to determine whether or not light shielding is necessary based on the luminance information, when the light shielding is necessary, the light shielding portion is in a shielding state, and when it is not necessary, the light shielding portion is transmitted. State. That is, by shielding external light with a light shielding part when necessary, it is possible to detect an occupant more accurately using a captured image, and by not shielding with a light shielding part when unnecessary, The visibility of the driver can be improved.

  According to the second invention, a plurality of light shielding portions are provided, and control of whether or not to enter a shielding state is performed for each light shielding portion. As a result, only the windows that need to be shielded can be shielded, and each light shielding unit can be controlled so that the windows that do not need to be shielded are not shielded. Necessary windows are shaded, so passengers can be detected more accurately using captured images, and unnecessary windows are not shaded, reducing driver visibility unnecessarily. Visibility can be improved more.

  According to the third invention, the vehicular imaging apparatus uses the arrangement pattern of the high-luminance area and the low-luminance area selected from the image areas to be imaged in order to select the light-shielding portion to be shielded. By using such an arrangement pattern, it is possible to easily estimate from which direction the external light is radiated to the imaging target, and it is possible to easily select a light shielding portion to be shielded.

  According to the fourth aspect, when it is determined that the luminance of each partial region in the image region to be imaged is high, the control unit sets all the light shielding units to a shielding state. Here, in the above case, since the external light transmitted through each window is too strong as a whole, the brightness of the image to be imaged is too high, so that the contour or feature point of the imaged object may not be detected accurately. There is. On the other hand, according to the fourth invention, in the above case, since all the light shielding portions can be in the shielding state, the illuminance in the passenger compartment can be lowered as a whole, and image recognition can be performed. Processing can be performed accurately.

  According to the fifth aspect, depending on whether the left or right side of the image area to be imaged has high brightness, one of the light shielding portions provided in the windows of the left and right doors is in a shielding state. According to this, even if it is a case where external light irradiates through either of the left and right door windows, only the necessary windows can be shielded accurately.

  According to the sixth invention, when the lower side of the image area to be imaged has high brightness, the light shielding portion provided on the front window is in a shielding state. According to this, when the external light is irradiated through the front window, only the necessary window can be shielded accurately.

  According to the seventh aspect of the present invention, the window glass and the liquid crystal panel can be integrally configured by configuring the light shielding portion with the liquid crystal panel, so that space saving of the vehicle can be achieved.

  Hereinafter, an imaging device for a vehicle according to an embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a configuration of a vehicle imaging device according to the present embodiment. In FIG. 1, the vehicle imaging device includes a camera 1, an ECU (Electrical Control Unit) 2, a right light shielding device 3 a, a front light shielding device 3 b, a left light shielding device 3 c, and a vehicle safety system 4. The vehicle imaging device shown in FIG. 1 is mounted on a vehicle, images a vehicle occupant (driver in this embodiment) with the camera 1, and uses the captured image to detect the occupant's state (for example, the driver looks aside). Or whether you are asleep. Hereinafter, each configuration shown in FIG. 1 will be described in detail.

(Configuration of vehicle imaging device)
The camera 1 is an example of the imaging unit described in the claims, and images an imaging target (occupant, more specifically, a driver) in the passenger compartment. The camera 1 is arranged at a position where an imaging target can be imaged. In the present embodiment, the camera 1 is disposed on the steering column of the vehicle so as to capture the driver's face so that the imaging direction is rearward (and slightly upward). Hereinafter, an image captured by the camera 1 is referred to as a captured image. The camera 1 outputs the captured image to the ECU 2.

  In other embodiments, the vehicle imaging device may further include an illumination device that illuminates the imaging target. As a result, even when the interior of the vehicle is dark, such as when traveling at night or in a tunnel, the imaging object can be imaged with high sensitivity. For example, an imaging means (typically a near infrared CCD camera) having high sensitivity characteristics in the near infrared region may be used as the camera 1 and an infrared LED may be used as the illumination device.

  The ECU 2 is an example of a control unit described in the claims, and includes an information processing device such as a microcomputer and a storage device such as a memory. The ECU 2 executes various control processes by executing a program stored in advance in the storage device. Specifically, the ECU 2 acquires a captured image from the camera 1 and controls the light shielding devices 3a to 3c based on the captured image. The ECU 2 detects the state of the driver by performing image recognition processing on the captured image, and outputs the detection result to the vehicle safety system 4. In the present embodiment, the ECU 2 detects the direction of the driver's face and the degree of opening of the driver's eyes (eyelids) (called the eyelid opening).

  In the present embodiment, the ECU 2 has a main microcomputer 5 and a sub-microcomputer 6. The main microcomputer 5 controls each of the light shielding devices 3a to 3c and detects the face direction of the driver. On the other hand, the sub-microcomputer 6 detects the heel opening. In the present embodiment, the configuration in which the ECU 2 includes two microcomputers has been described as an example. However, in other embodiments, the control unit described in the claims may be realized by one microcomputer. Moreover, in this embodiment, although the microcomputer which performs the process which detects a driver | operator's state, and the microcomputer which controls each light-shielding apparatus 3a-3c shall be the same, the control part as described in a claim is each light-shielding. It may be an information processing device that controls the devices 3a to 3c, and may be configured separately from a device (circuit) that detects the state of the driver.

  Each of the light shielding devices 3a to 3c is an example of a light shielding unit described in the claims, and has a function of shielding external light that passes through the window of the vehicle and irradiates the vehicle interior. Each light-shielding device 3a-3c can take the shielding state which shields the external light which permeate | transmits a window, and the permeation | transmission state which permeate | transmits the said external light, and switches a shielding state and a permeation | transmission state according to the control instruction | command of ECU2. Is possible. In the present embodiment, each of the light shielding devices 3a to 3c includes a liquid crystal panel and a drive circuit for the liquid crystal panel. That is, the liquid crystal panel has a configuration in which liquid crystal is sealed between two transparent plates. A drive circuit changes the transmittance | permeability of a liquid crystal panel by controlling the voltage applied to the electrode formed in the transparent plate of a liquid crystal panel according to the control instruction | indication of ECU2. The light shielding device only needs to be able to switch between the shielding state and the transmission state, and can take an intermediate state between the shielding state and the transmission state as in the liquid crystal panel (that is, the transmittance is continuously changed). The configuration may be possible. Further, the transmission state does not need to be a state in which external light is completely transmitted in a strict sense, and may be a state in which external light is transmitted at least as compared with the shielding state.

  The right light shielding device 3a is provided in a right front window of the vehicle, the front light shielding device 3b is provided in a front window of the vehicle, and the left light shielding device 3c is provided in a left front window of the vehicle. In the present embodiment, the ECU 2 can individually control the light shielding devices 3a to 3c. For example, only the right light shielding device 3a is in a shielding state, and the front light shielding device 3b and the left light shielding device 3c are in a transmissive state. It is also possible. Note that each of the light shielding devices 3a to 3c does not need to shield the entire surface of the window, and it is sufficient that at least external light applied to the imaging target (driver's face) can be shielded. In this embodiment, the case where the light shielding devices are provided in the three windows of the vehicle has been described as an example. However, the number of the light shielding devices may be any number as long as the number is one or more.

  In the present embodiment, the light shielding device includes a liquid crystal panel. However, the light shielding device may be any device that can switch between a shielding state and a transmission state. In other embodiments, the light shielding device may be, for example, glass using an electrochromic material (electrochromic glass). When the liquid crystal panel or the electrochromic glass is used as a light-shielding device, the liquid crystal panel or the electrochromic glass can also serve as a window glass, so that space saving of the device can be achieved.

  Further, the light shielding device may be a blind that moves up and down in accordance with a control instruction from the ECU 2. A blind is a structure which can roll up and take out the sheet wound, for example by roll shape with a motor. Such a blind is attached to, for example, the upper side of the window, and a sheet is taken out to cover the window with the sheet, thereby shielding external light from the window. When the blind is used as a light-shielding device, the blind is not limited to shielding all wavelengths of light, but may be one that blocks only a part of the wavelengths. For example, when the camera 1 is an infrared camera, the blind may at least block infrared light, or may block visible light so that the driver does not feel external light dazzling. It may be a thing. When the blind is used as a light shielding device, external light can be shielded even when the window is opened.

  The vehicle safety system 4 warns the driver before the collision, avoids the collision (for example, control of the brake), and reduces the damage at the time of the collision (for example, pulls the seat belt at the time of the collision) based on the state of the driver detected by the ECU 2 ) And the like for performing the operation for maintaining the safety of the vehicle. In the present embodiment, it is assumed that the vehicle safety system 4 is a control device that performs control to change the timing for giving a warning to the driver according to the state of the driver.

(Operation of imaging device for vehicle)
Next, with reference to FIGS. 2 to 5, the operation of the vehicle imaging device configured as described above will be described. FIG. 2 is a flowchart showing processing executed by the ECU 2 of the vehicle imaging device. The process shown in FIG. 2 is started in response to the vehicle power being turned on (ignition power or accessory power is turned on), and is executed while the vehicle power is on. In another embodiment, the process shown in FIG. 2 may be executed while the vehicle is traveling.

  In step S <b> 1, the ECU 2 acquires a captured image from the camera 1. The acquired captured image includes an image of the driver's face (face image). Note that the process of step S1 is repeatedly executed at a rate of once per predetermined time. Following step S1, the process of step S2 is executed.

  In subsequent step S2, ECU 2 calculates the luminance distribution (luminance value of each pixel) of the face region from the captured image acquired in step S1. The face area is a face image area in the captured image area. That is, the ECU 2 calculates a luminance value for each pixel included in the face area. Area information indicating an area to be imaged (face area) is stored in a storage device in the ECU 2, and the ECU 2 identifies the face area with reference to the area information. Specifically, the ECU 2 calculates a luminance value from the captured image for the pixels in the region indicated by the region information among the pixels constituting the captured image.

  The content of the region information may be determined in advance, but is preferably updated as appropriate. This is because the face area changes depending on the person who becomes the driver, and also changes depending on the posture of the driver, so that an accurate face area is set in accordance with such a change. For example, the ECU 2 may calculate the contour of the driver's face based on the captured image acquired at the time when the processing shown in FIG. 2 is started, and store information indicating the region in the contour as region information. Good. Further, the ECU 2 may execute the face area update process at predetermined time intervals during the execution of the process shown in FIG. In order to obtain an accurate face area, the update process of the face area is performed when the imaging target is correctly recognized in the image recognition process of the imaging target (driver's face) (for example, the determination result in step S7 described later) This is preferably executed when the result is affirmative or when the result of determination in step S4 described later is negative. That is, it is preferable that the ECU 2 executes the update process of the face area based on the captured image used in the image recognition process in the above case.

  Following step S2, the process of step S3 is executed. In step S3, the ECU 2 determines, based on the luminance distribution calculated in step S2, a region having a relatively high luminance (high luminance region) and a region having a relatively low luminance (low luminance region) in the face region. And elect. In this embodiment, ECU2 which performs step S2 is equivalent to the area | region selection part as described in a claim. Hereinafter, with reference to FIG. 3 and FIG. 4, the selection method of a high-intensity area | region and a low-intensity area | region is demonstrated.

  3 and 4 are diagrams illustrating an example of a captured image. In the present embodiment, the face area is divided into a plurality of partial areas in order to select a high luminance area and a low luminance area. Specifically, as shown in FIGS. 3 and 4, the face area 11 is divided into four partial areas, that is, an upper left area 12, an upper right area 13, a lower left area 14, and a lower right area 15. Here, the ECU 2 divides the face region 11 into the four partial regions 12 to 15 by dividing the face region 11 into two in the vertical direction at the center position of the face region 11 and dividing into two in the left and right direction at the center position. As described above, according to the method of setting a partial region using the region information (for example, information indicating the outline of a face), the feature point of the face is not required to set the partial region. Even if it cannot be detected, a partial region can be set. In another embodiment, the ECU 2 may set a partial region based on a feature point obtained as a result of the image recognition process in addition to the region information or instead of the region information. Specifically, the ECU 2 identifies the position of the nose by image recognition processing, and divides the face area 11 into the four partial areas 12 to 15 by dividing the nose position in the vertical and horizontal directions, respectively. May be. In the present embodiment, the case where the face area is divided into four partial areas 12 to 15 has been described as an example. However, in other embodiments, the number of partial areas may be any number.

  In the present embodiment, in step S <b> 2, the ECU 2 performs a specifying process for specifying whether each of the partial areas 12 to 15 is a high-luminance area or a low-luminance area. Specifically, first, the ECU 2 calculates the luminance of each of the partial areas 12-15. For example, the average value of the luminance of the pixels in the partial area is calculated as the luminance of the partial area. That is, ECU2 calculates the average value of the brightness | luminance of the pixel in a (1) partial area for every partial area 12-15. Next, the ECU 2 determines whether or not the brightness of all the partial areas 12 to 15 is higher than a predetermined reference, that is, whether or not the brightness of all the partial areas 12 to 15 is equal to or higher than a predetermined first threshold value. Determine. If the result of this determination is affirmative, all of the partial areas 12 to 15 are specified as high brightness areas. On the other hand, when the result of the determination is negative, the ECU 2 determines that the luminance of the two partial areas is higher than the predetermined second threshold value when the difference between the luminance of the certain partial area and the luminance of the other partial area is greater than or equal to a predetermined second threshold value. The higher one is the high luminance region, and the lower one is the low luminance region. The first threshold value and the second threshold value are stored in a storage device in the ECU 2 and may be predetermined fixed values, for example, time (whether it is nighttime or daytime), The value may vary according to the environment (illuminance or weather) around the vehicle.

  By the specifying process, a high luminance region and a low luminance region are specified from among the partial regions 12 to 15. In the above identification process, not all of the partial areas 12 to 15 are necessarily specified as a high luminance area or a low luminance area. However, in other embodiments, all of the partial areas 12 to 15 are high. It may be specified as either a luminance region or a low luminance region.

  FIG. 3 shows a captured image in a case where external light is transmitted through the window on the right front side of the vehicle and external light is irradiated from the left side of the driver (as viewed from the front of the driver). In this case, as shown in FIG. 3, light hits the lower left part of the driver's face (as viewed from the front of the driver). Therefore, in this case, typically, only the lower left region 14 is a high luminance region, and the upper left region 12, the upper right region 13, and the lower right region 15 are low luminance regions.

  On the other hand, FIG. 4 shows a captured image in a case where external light is transmitted through the front window of the vehicle and external light is emitted from the front of the driver. In this case, as shown in FIG. 4, light hits the lower part of the driver's face. Therefore, in this case, typically, the lower left region 14 and the lower right region 15 are high luminance regions, and the upper left region 12 and the upper right region 13 are low luminance regions.

  As described above, in the present embodiment, the vehicular imaging apparatus divides the face area 11 into a plurality of partial areas, and determines whether or not light is applied to each partial area. According to this, it can be easily estimated from which direction the external light is applied to the driver's face. For example, when the captured image shown in FIG. 3 is obtained, it can be inferred that external light is emitted from the window on the right front side of the vehicle. When the captured image shown in FIG. It can be assumed that external light is radiated from the window. Although details will be described later, in the present embodiment, the vehicular imaging apparatus uses the arrangement pattern of the high luminance region and the low luminance region to estimate the direction in which the external light is applied to the driver's face. It is discriminated whether the light shielding device should be shielded.

  Returning to the description of FIG. 2, in step S4 following step S3, the ECU 2 determines whether or not the window needs to be shielded from light. Specifically, this determination is made based on whether or not at least one partial region is specified as a high luminance region in step S3. When at least one partial region is specified as the high luminance region, it is determined that the window needs to be shielded, and the processes of steps S5 and S6 are executed. On the other hand, when none of the partial areas is specified as the high luminance area, it is determined that it is not necessary to shield the window, the processing of steps S5 and S6 is skipped, and step S7 described later is executed.

  In step S5, the ECU 2 selects a light shielding device that should be in a shielding state among the light shielding devices 3a to 3c. The selection in step S5 is performed based on the luminance distribution in the face region 11, that is, based on the arrangement pattern of the high luminance region and the low luminance region. In this embodiment, ECU2 which performs step S5 is equivalent to the shielding selection part as described in a claim. Further, the ECU 2 stores information (typically a table) that associates the arrangement pattern of the high-luminance area and the low-luminance area with the light shielding device to be shielded in the case of the arrangement pattern. The selection in step S5 is performed using this table.

  FIG. 5 is a diagram illustrating an example of a table in which arrangement patterns and light shielding devices are associated with each other. In the table shown in FIG. 5, light shielding devices that should be in a shielding state are associated with six types of arrangement patterns. Specifically, the right light-shielding device 3a is associated with an arrangement pattern in which only the lower left area 14 is a high luminance area, and an arrangement pattern in which the upper left area 12 and the lower left area 14 are high luminance areas. Further, the left light shielding device 3c is associated with an arrangement pattern in which only the lower right area 15 is a high luminance area and an arrangement pattern in which the upper right area 13 and the lower right area 15 are high luminance areas. Further, the front light shielding device 3b is associated with the arrangement pattern in which the lower left region 14 and the lower right region 15 are high luminance regions. Moreover, all the light shielding devices 3a to 3c are associated with the arrangement pattern in which all the partial regions 12 to 15 are high luminance regions.

  In the selection process of step S5, the ECU 2 selects the light shielding device associated in the table with respect to the arrangement pattern specified in step S3, as the light shielding device that should be in the shielding state. For example, when the arrangement pattern identified in step S3 is an arrangement pattern in which only the lower left area 14 is a high luminance area, or an arrangement pattern in which the upper left area 12 and the lower left area 14 are high luminance areas, the right light shielding device 3a. Is selected. In the present embodiment, when the arrangement pattern specified in step S3 is an arrangement pattern that is not included in the table, the light shielding device is not selected. Following step S5, the process of step S6 is executed.

  In step S6, the ECU 2 gives a control instruction for setting the shielding state to the light shielding device selected in step S5. When this control instruction is given to the light shielding device, the light shielding device operates to be in a light shielding state, and as a result, the window is shielded from light. The ECU 2 only needs to shield at least external light applied to the imaging target (driver's face), and may shield the entire liquid crystal panel, which is the selected light shielding device, or may partially shield the light. . Note that if the light shielding device is not selected in step S5, the ECU 2 does not give a control instruction. Following step S6, the process of step S7 is executed.

  As a result of the processing in steps S1 to S6 described above, the vehicular imaging apparatus irradiates the driver's face with external light. As a result, the brightness of the face image included in the captured image is too high, or the brightness of the face image If the difference is too large, the light shielding device at an appropriate position can be put in a shielding state so as to shield external light. In addition, although the process of said step S1-S6 shall be performed by the main microcomputer 5 of ECU2, in other embodiment, the submicrocomputer 6 may perform the said process, and the main microcomputer 5 and The sub-microcomputer 6 may cooperate to execute the process.

  In steps S7 to S9, a process for detecting the state of the driver using the captured image acquired in step S1 is executed. Note that the processing in steps S7 to S9 is an example, and the present invention can be applied to a system that performs some kind of image recognition processing on an image of a captured image.

  In step S7, the ECU 2 executes a process for detecting the driver's face orientation (face orientation detection process). The face orientation detection process is executed by the main microcomputer 5 of the ECU 2. The face orientation detection process is performed as follows, for example. First, the main microcomputer 5 calculates the positions of the left end and the right end of the driver's face by extracting the contour of the driver's face from the captured image. Next, the center position of the driver's face is calculated by specifying the position of the driver's nose from the captured image. Further, the direction of the driver's face is calculated based on the ratio of the length from the left end position to the center position and the length from the right end position to the center position. When the driver's face orientation is calculated as described above, the process of step S8 is then executed.

  In step S8, the ECU 2 determines whether or not the driver's face orientation could be detected in step S7. The case where the face orientation cannot be detected in step S7 is, for example, the case where the contour of the driver's face cannot be extracted and the position of the left end and / or right end of the face cannot be calculated, For example, the position of the driver's nose cannot be specified, and the center position of the face cannot be calculated. One reason that the face orientation cannot be detected as in these cases is that the brightness of the face image included in the captured image is too high as a result of external light being applied to the driver's face, It is possible that the difference in brightness is too large. If the determination result of step S8 is affirmative, the process of step S9 is executed. On the other hand, if the determination result of step S8 is negative, the process of step S1 described above is executed again.

  In step S9, the ECU 2 executes a process for calculating the degree of opening of the driver's eyes (a lid opening degree detection process). Note that the lid opening degree detection process is executed by the sub-microcomputer 6 of the ECU 2. The lid opening degree detection process is performed, for example, as follows. First, the sub-microcomputer 6 calculates a range for searching for the driver's eyes from the position of the nose calculated in the face orientation calculation process. Next, the eye (eye width) is searched and detected within the calculated range, and the degree of opening (opening degree) is calculated from the detected eye. After the eaves opening is calculated as described above, the process of step S10 is executed next.

  In the present embodiment, the face opening degree detection process (step S9) is executed after the face direction detection process (step S7) ends, but the face direction detection process and the eyelid opening degree detection process are different. Since it is executed by the information processing apparatus (main microcomputer 5 and sub-microcomputer 6), a part or all of these two processes may be executed in parallel. By executing the face orientation detection process and the eyelid opening detection process in parallel, the processing time of the process for detecting the driver's state can be shortened. If the two processes are not executed in parallel, the ECU 2 may include only the main microcomputer 5.

  In step S10, the ECU 2 outputs information indicating the state of the driver detected in steps S7 and S9 to the vehicle safety system 4. The vehicle safety system 4 having input the information performs control according to the driver's state. For example, when the vehicle safety system 4 determines that the driver is more tired than usual from the information, the vehicle safety system 4 sets the timing for issuing a warning to the driver earlier than the normal time. After step S10, the process of step S1 is executed again. Thereafter, the processing loop of steps S1 to S10 is repeatedly executed until the condition for ending the processing shown in FIG. 2 is satisfied (for example, until the vehicle is turned off).

  In the process of the flowchart described above, a process for detecting the state of the driver by the image recognition process is performed regardless of the determination result (step S4) whether or not the window needs to be shielded from light. Here, in another embodiment, when it is determined that the window needs to be shielded (Yes in step S4), the ECU 2 does not perform the processes in steps S7 to S10 after step S6, but in step S1. You may make it return to a process. This is because the image recognition process may not be performed accurately in the above case.

  As described above, according to the present embodiment, the vehicle imaging device sets the light shielding devices 3a to 3c in the shielding state based on the luminance of the image of the imaging target (driver's face) in the captured image. Controls whether to make it transparent. As a result, since the external light is shielded for the portion of the vehicle window that needs to be shielded, it is possible to prevent the imaging target from being accurately detected by the external light. Moreover, since the light-shielding device is maintained in the transmissive state for portions of the vehicle window that do not require light-shielding, visibility can be improved.

  For example, as shown in FIG. 3, when only the lower left region 14 of the face region 11 is a high luminance region, strong external light is transmitted through the window on the right front side and irradiates the driver's face. Conceivable. Therefore, in this case, the ECU 2 puts the right light shielding device 3a corresponding to the right front window into a shielding state, and places the front light shielding device 3b and the left light shielding device 3c into a transmission state. Accordingly, external light from the right front window that needs to be shielded can be shielded, and visibility of other windows that do not need to be shielded can be maintained by setting the light shielding device in a transmissive state. The ECU 2 is not limited to the above case, and the left region of the face region 11 is higher in luminance than the right region by a predetermined reference (for example, the upper left region 12 and the lower left region 14 are high luminance regions). The right light-shielding device 3a is preferably in a shielding state. Conversely, the ECU 2 determines that the right area of the face area 11 has a higher brightness than the left area by a predetermined reference (for example, when the upper right area 13 and the lower right area 15 are high intensity areas). It is preferable that the side light-shielding device 3c is in a shielding state.

  Also, as shown in FIG. 4, when the lower left region 14 and the lower right region 15 of the face region 11 are high luminance regions, strong external light is transmitted through the front window and irradiates the driver's face. It is thought that there is. Therefore, in this case, the ECU 2 puts the front light-shielding device 3b corresponding to the front window into a shielding state, and places the right light-shielding device 3a and the left light-shielding device 3c into a transmissive state. Accordingly, external light from the front window that needs to be shielded can be shielded, and the visibility of other windows that do not need to be shielded can be maintained by setting the light shielding device in a transmissive state. As described above, when the luminance of the lower region of the face region 11 is higher than a predetermined reference in the lower region (in the case of FIG. 4), the ECU 2 may set the front light shielding device 3b in a shielding state. preferable.

  Further, when the brightness of all the partial areas 12 to 15 in the face area 11 is higher than a predetermined reference (specifically, when all the partial areas 12 to 15 are high brightness areas), each window is displayed. The transmitted external light is considered to be too strong overall. In such a case, if only some of the light-shielding devices are in the shielding state, a luminance difference (brightness / darkness) occurs in the driver's face, and there is a possibility that the image recognition process cannot be performed accurately. Therefore, in this case, the ECU 2 puts all the light shielding devices 3a to 3c into a shielding state. Thereby, the illuminance in the passenger compartment can be lowered as a whole, and the image recognition process can be performed accurately.

  In addition, according to the above embodiment, when the driver's face is irradiated with strong external light, the external light can be blocked, so that the driver feels the external light dazzling and hinders driving. Can be prevented. In addition, when the driver's face is irradiated with strong external light, the driver may squint. However, if the driver squints, the ECU 2 performs “driving” in the eyelid opening degree detection process described above. May mistakenly determine that the person is staring. However, in this embodiment, for example, when strong light is radiated on the entire driver's face, the exterior of the driver's face is irradiated so that all the light shielding devices 3a to 3c are in a shielding state. Since the light can be shielded, it is possible to prevent the driver from narrowing his eyes because the external light is dazzling.

  As described above, the present invention can be used as, for example, an imaging device mounted on a vehicle for the purpose of improving the visibility of an occupant and more accurately detecting the occupant using a captured image. It is.

Block diagram showing the configuration of an imaging device for a vehicle The flowchart which shows the process which ECU2 of the imaging device for vehicles performs The figure which shows an example of a captured image The figure which shows an example of a captured image The figure which shows an example of the table which linked | related the arrangement pattern and the light-shielding apparatus

Explanation of symbols

1 Camera 2 ECU
3a-3c Shading device 4 Vehicle safety system

Claims (7)

An imaging device for a vehicle mounted on a vehicle,
A light shielding portion that is provided in the window of the vehicle and can take a shielding state that shields at least a part of the external light that passes through the window and a transmission state that transmits the external light rather than the shielding state;
An imaging unit for imaging an imaging target in the passenger compartment;
A vehicle having a control unit that obtains luminance information about the imaging target from an image captured by the imaging unit and controls whether the light shielding unit is in the shielding state or the transmission state based on the luminance information; Imaging device. The light shielding portion is provided in each of the plurality of windows of the vehicle,
The vehicle imaging device according to claim 1, wherein the control unit selects a light shielding unit to be in the shielding state among the light shielding units based on a luminance distribution in the image region to be imaged. The controller is
An area selection unit that selects a high-brightness area having a relatively high luminance and a low-brightness area having a relatively low luminance from the image areas to be imaged in the captured image;
The vehicle imaging according to claim 2, further comprising: a shielding selection unit that selects a light shielding unit to be in the shielding state among the light shielding units based on an arrangement pattern of the high luminance region and the low luminance region. apparatus.   The control unit determines whether or not the brightness is higher than a predetermined reference for each of the partial areas obtained by dividing the image area to be imaged in the captured image into a plurality of the partial areas. The vehicular imaging device according to claim 2, wherein when it is determined that the luminance is higher than a predetermined reference, all of the light shielding portions are in the shielding state. The imaging unit is arranged to image the driver seat from the front to the rear of the driver seat of the vehicle,
Two of the light shielding portions are respectively provided in the windows of the right and left doors,
When the left area of the image area to be imaged has a luminance higher than a predetermined reference compared to the right area, the controller sets the light shielding section provided in the right door window in a shielding state, The light shielding part provided in the window of the left door is in a shielding state when the right area of the image area to be imaged has a brightness higher than a predetermined reference compared to the left area. An imaging device for a vehicle. The imaging unit is arranged to image the driver seat from the front to the rear of the driver seat of the vehicle,
One of the light shielding portions is provided on a front window of the vehicle,
The said control part makes a light-shielding part provided in the said front window into a shielding state, when the lower area | region among the said image area | regions of the imaging object has a brightness | luminance more than a predetermined reference | standard compared with an upper area | region. The vehicle imaging device according to 2.   The vehicular imaging apparatus according to claim 1, wherein the light shielding portion is configured by a liquid crystal panel.

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