Imaging control device and imaging control method

Abstract

An imaging control device (100) comprises: an imaging unit (10) that images, in the same field of view, a first location and a second location different from the first location; a first emission unit (21) that emits light toward the first location; a second emission unit (22) that emits light toward the second location; a brightness information acquisition unit (532) that acquires information pertaining to the brightness of the first location and information pertaining to the brightness of the second location; and an emission time control unit (53) that, on the basis of the information acquired by the brightness information acquisition unit, controls the light emission times of the first emission unit and the second emission unit in an exposure time, during which the imaging unit performs imaging, such that the time during which light is emitted toward the one location, from among the first location and the second location, that has the lower brightness is longer than the time during which light is emitted toward the other location.

Description

[Technical Field]

[0001] The present disclosure relates to an imaging control device and an imaging control method. [Background technology]

[0002] BACKGROUND ART Conventionally, a vehicle has been disclosed that is equipped with a camera that photographs the interior of the vehicle, and that photographs multiple occupants in the vehicle with one camera to acquire information about the multiple occupants (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-190504 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, when a camera or the like captures images of multiple objects located at different positions within the same field of view, the brightness of the imaged objects may differ depending on the positions of the objects. However, the vehicle described in Patent Document 1 has a problem in that, when the brightness differs depending on the positions of the occupants, it may not be possible to obtain information accurately enough about the occupants located in dark positions.

[0005] The present disclosure is intended to solve the above-described problems, and has an object to provide an imaging control device and an imaging control method that can improve the accuracy of information acquisition. [Means for solving the problem]

[0006] An imaging control device according to the present disclosure includes an imaging unit that images a first position and a second position different from the first position within the same field of view, a first irradiation unit that irradiates light toward the first position, a second irradiation unit that irradiates light toward the second position, a brightness information acquisition unit that acquires information related to the brightness of the first position and information related to the brightness of the second position, and an irradiation time control unit that controls, based on the information acquired by the brightness information acquisition unit, the irradiation time of light by the first irradiation unit and the second irradiation unit during an exposure time during which imaging is performed by the imaging unit, so that the time during which light is irradiated toward one of the first and second positions, which is less bright, is longer than the time during which light is irradiated toward the other position. a detection unit that detects a specific object located within the field of view; Equipped with The irradiation time control unit controls the irradiation time of light to the one of the first position and the second position having the lower brightness so that, when the detection unit does not detect a specific object located at the one of the first position and the second position having the lower brightness, the irradiation time of light to the one of the first position and the second position having the lower brightness is shorter than when the detection unit detects a specific object. It is characterized by: [Effects of the Invention]

[0007] According to the present disclosure, the irradiation time of light toward the position to be imaged is controlled based on information regarding the brightness of the position to be imaged, thereby making it possible to suppress differences in brightness between multiple positions and improving the accuracy of information acquisition. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic plan view showing an occupant monitoring system according to a first embodiment. [Figure 2] 1 is a block diagram showing the configuration of an occupant monitoring system according to a first embodiment. [Figure 3] 1 is a block diagram showing an example of a hardware configuration of an imaging control device according to a first embodiment. [Figure 4] 1 is a block diagram showing an example of a hardware configuration of an imaging control device according to a first embodiment. [Figure 5] 4 is a flowchart showing processing performed by the imaging control device according to the first embodiment. [Figure 6] 4 is a timing chart showing the exposure time of an imaging unit and the irradiation time of an irradiation unit controlled by the imaging control device according to the first embodiment. [Figure 7]FIG. 10 is a schematic plan view showing an occupant monitoring system according to a second embodiment. [Figure 8] FIG. 10 is a block diagram showing the configuration of an occupant monitoring system according to a second embodiment. [Figure 9] 10 is a flowchart showing processing performed by an imaging control device according to the second embodiment. [Figure 10] 10 is a timing chart showing the exposure time of an imaging unit and the irradiation time of an irradiation unit controlled by an imaging control device according to the second embodiment. [Figure 11] 10 is a timing chart showing the exposure time of an imaging unit and the irradiation time of an irradiation unit controlled by an imaging control device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Embodiment 1 First, a schematic configuration of a vehicle according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic plan view of an occupant monitoring system 100 according to the first embodiment, and Figure 2 is a block diagram showing the configuration of the occupant monitoring system 100 according to the first embodiment. For example, the occupant monitoring system 100 is a system for detecting an occupant of the vehicle V1 by capturing an image of the interior S1 of the vehicle V1. Furthermore, for example, by analyzing the captured image information of the occupant detected by the occupant monitoring system 100 using an image analysis unit (not shown), it becomes possible to obtain information about the occupant, such as identification information of the occupant, position information of the occupant, posture information of the occupant, etc.

[0010] As shown in FIGS. 1 and 2, an occupant monitoring system 100 according to the first embodiment includes an imaging unit 10, an irradiation device 20, and an imaging control device 50. The imaging control device 50 is electrically connected to the imaging unit 10 and the irradiation device 20 so as to be able to transmit and receive information, and controls the imaging unit 10 and the irradiation device 20 based on information from the imaging unit 10. Note that the imaging control device 50 according to the first embodiment may be provided in an external device to which some of the functions described below are connected via a network. Note that in the first embodiment, the direction in front of a driver seated in a driver's seat P1 of a vehicle V1 in a driving position is defined as the forward direction, and the front-rear, up-down, left-right directions are defined based on this.

[0011] The illumination device 20 emits light to irradiate the interior S1 of the vehicle V1. For example, the illumination device 20 is configured with a plurality of LEDs and receives a current to irradiate the interior S1 of the vehicle V1 with infrared light. Furthermore, for example, the illumination device 20 has a plurality of illumination units that are arranged at different positions to emit light. Specifically, the illumination device 20 has a first illumination unit 21, a second illumination unit 22, a third illumination unit 23, and a fourth illumination unit, and the first to fourth illumination units 21 to 24 irradiate light toward each part of the interior S1 of the vehicle V1. For example, the first illumination unit 21 irradiates an illumination range 21a toward the driver's seat P1 of the vehicle V1, which is a first position. The second illumination unit 22 irradiates an illumination range 22a toward one of the rear seats P2 of the vehicle V1, which is a second position. The third irradiating unit 23 irradiates light onto an irradiation range 23a toward the passenger seat P3 of the vehicle V1. The fourth irradiating unit 24 irradiates light onto an irradiation range 24a toward the other rear seat P4 of the vehicle V1. Note that the first irradiating unit may be arranged to irradiate light onto a seat other than the driver's seat, and the second irradiating unit may be configured to irradiate light onto a seat other than one of the rear seats.

[0012] The imaging unit 10 captures an image within a specific field of view 10a inside the vehicle and outputs imaging information obtained by the imaging. In other words, the imaging unit 10 captures an image within the field of view 10a, which is a specific imaging range inside the vehicle, and outputs a signal corresponding to the imaging information obtained by the imaging. For example, the imaging unit 10 captures images of the driver's seat P1, one rear seat P2, a passenger seat P3, and the other rear seat P4 of the vehicle V1 within the same field of view. Furthermore, for example, the imaging unit 10 is configured by an infrared camera having an image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0013] The imaging control device 50 includes an exposure time control unit 51, an occupant detection unit 52, and an irradiation time control unit 53. The exposure time control unit 51 controls the exposure time during which imaging is performed by the imaging unit 10. For example, the exposure time calculation unit 511 calculates the length of the exposure time during which imaging is performed by the imaging unit 10 based on information from the imaging unit 10 and information from the irradiation time control unit 53. The exposure time control unit 51 includes the exposure time calculation unit 511 and an exposure time setting unit 512. The exposure time setting unit 512 sets the exposure time calculated by the exposure time calculation unit 511. The exposure time setting unit 512 also outputs a control signal to the imaging unit 10 according to the exposure time set by the exposure time setting unit 512 and a preset exposure frequency. In other words, the exposure time setting unit 512 outputs a control signal to the imaging unit 10 according to the exposure time set by the exposure time setting unit 512 and a preset exposure start timing.

[0014] The occupant detection unit 52 detects an occupant in the interior S1 of the vehicle V1 as a specific target. In other words, the occupant detection unit 52 detects an occupant located within the field of view of the image capture unit 10. For example, the occupant detection unit 52 detects an occupant located within the field of view of the image capture unit 10 based on imaging information obtained by the image capture unit 10, and outputs a signal according to the detection result. Specifically, the occupant detection unit 52 detects the presence or absence of an occupant for each seat of the vehicle V1 based on the imaging information obtained by the image capture unit 10. Note that the occupant detection unit 52 may be configured to detect the presence or absence of an occupant using a sensor (not shown) that detects whether a seat belt is fastened in each seat, a weight sensor that detects the weight on each seat, or other sensors (not shown).

[0015] The irradiation time control unit 53 controls the irradiation time of light by the irradiation device 20 based on the imaging information obtained by the imaging unit 10 and the detection result of the occupant by the occupant detection unit 52. The irradiation time control unit 53 has a brightness target value setting unit 531, a brightness information acquisition unit 532, a brightness determination unit 533, an irradiation time calculation unit 534, and an irradiation time setting unit 535.

[0016] The brightness target value setting unit 531, which serves as a target value acquisition unit, acquires a target value for brightness acquired from each seat by the image capture unit 10 and sets the acquired target value. In other words, it acquires and sets a target value for brightness for each seat in the image capture information, and then sets the acquired target value. For example, the brightness target value setting unit 531 sets a target value for brightness for each seat in the image capture information such that, when the image capture unit 10 captures an image of the interior S1 of the vehicle V1, the image capture unit 10 can acquire a sufficient amount of light from each seat. In other words, it sets a target value so that the image capture information acquired by the image capture unit 10 is bright enough to detect occupants. For example, the brightness target value set by the target value setting unit 531 is a digital signal value (DN; Digital Number) of the image sensor. The digital signal value refers to a value (without physical quantity) obtained by converting the amount of photons received by the photodiode of the image sensor into a voltage and then AD-converting the converted voltage. Specifically, if the digital signal value is 8 bits, the target brightness value is 0x80, and the digital signal value DN corresponding to the actual brightness of the seat (occupant) is 0x40, the actual brightness can be said to be half of the target value. In such a case, the irradiation time control unit 53 can adjust the digital signal value DN corresponding to the actual brightness of the seat so that it reaches the target value by doubling the light emission time of the light source to double the radiant flux (W).

[0017] The brightness target value setting unit 531 may be configured to acquire the target value from another component of the imaging control device 50 (not shown), or may be configured to acquire the target value from a device external to the imaging control device 50 (not shown), or may be configured to acquire the target value based on a signal from an input device (not shown) operated by an operator, or may be configured so that the brightness target value setting unit 531 sets the target value based on various conditions, thereby acquiring the target value. Furthermore, the brightness target value setting unit 531 may be configured to set the target value as a single value, or may be configured to set a lower limit target value and an upper limit target value that indicate a target range, or may be configured to set different target values ​​for each seat.

[0018] The brightness information acquisition unit 532 acquires information about the brightness in the interior S1 of the vehicle V1. For example, the brightness information acquisition unit 532 acquires information about the brightness of each seat in the vehicle V1. Specifically, the brightness information acquisition unit 532 acquires information about the amount of light acquired from each of the driver's seat P1, one rear seat P2, the passenger seat P3, and the other rear seat P4 of the vehicle V1 based on imaging information acquired by imaging the imaging unit 10. For example, the brightness information acquisition unit 532 acquires information indicating the amount of light acquired from each seat in the vehicle V1 based on image analysis of the imaging information acquired by imaging the imaging unit 10.

[0019] The brightness determination unit 533 determines whether the brightness in the interior S1 of the vehicle V1 reaches the target value set by the brightness target value setting unit 531, based on the information about the brightness of the interior S1 of the vehicle V1 acquired by the brightness information acquisition unit 532. For example, the brightness determination unit 533 determines whether the amount of light acquired from each seat reaches the target value by comparing the brightness of each seat in the vehicle V1 in the imaging information with the target value for brightness set by the brightness target value setting unit 531. In other words, the brightness determination unit 533 determines whether the imaging information obtained by imaging by the imaging unit 10 has sufficient brightness corresponding to the target value.

[0020] The irradiation time calculation unit 534 calculates the irradiation time of light by the irradiation device 20 based on the information about the brightness of the interior S1 of the vehicle V1 acquired by the brightness information acquisition unit 532. Specifically, the irradiation time calculation unit 534 calculates the irradiation time of light by each of the first to fourth irradiators 21 to 24 so as to reduce the difference in brightness between the seats based on the information about the brightness of the interior S1 of the vehicle V1 acquired by the brightness information acquisition unit 532. For example, the irradiation time calculation unit 534 calculates the length of continuous irradiation time of each of the first to fourth irradiators 21 to 24 so as to reduce the difference in brightness between the seats based on the information about the brightness of the interior S1 of the vehicle V1 acquired by the brightness information acquisition unit 532.

[0021] The irradiation time setting unit 535 sets the time for irradiating light by the irradiation device 20 calculated by the irradiation time calculation unit 534. For example, the irradiation time setting unit 535 outputs a current for causing the irradiation device 20 to emit light according to the set irradiation time to each of the first to fourth irradiating units 21 to 24. Furthermore, for example, the irradiation time setting unit 535 outputs a control signal for causing the irradiation device 20 to emit light based on the set irradiation time to each of the first to fourth irradiating units 21 to 24.

[0022] Next, the hardware configuration of the imaging control device 50 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram showing an example of the hardware configuration of the imaging control device 50 according to the first embodiment, and FIG. 4 is a block diagram showing an example of a hardware configuration of the imaging control device 50 according to the first embodiment, which is different from that shown in FIG. 3. For example, as shown in FIG. 3, the imaging control device 50 includes a processor 50a, a memory 50b, and an I / O port 50c, and is configured so that the processor 50a reads and executes a program stored in the memory 50b. The memory 50b may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM. The memory 50b may also be a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisc, a DVD, or the like. The memory 50b may also be an HDD or an SSD.

[0023] 4, the imaging control device 50 also includes a processing circuit 50d and an I / O port 50c, which are dedicated hardware. The processing circuit 50d is configured, for example, by a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a system LSI (Large-Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each function of the imaging control device 50 is realized by the processor 50a or the processing circuit 50d, which is dedicated hardware, executing a program, which is software, firmware, or a combination of software and firmware.

[0024] Next, details of the processing performed by the imaging control device 50 according to the first embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a flowchart showing the processing performed by the imaging control device 50 according to the first embodiment. As shown in Fig. 5, when the processing starts, the imaging control device 50 sets a target value X for the brightness of each seat of the vehicle V1 (step ST1). In this processing, the brightness target value setting unit 531 sets a target value for the brightness of each seat in the imaging information obtained by imaging by the imaging unit 10.

[0025] After performing the process of step ST1, the imaging control device 50 causes the imaging unit 10 to capture an image of the interior of the vehicle V1 (step ST2). In this process, the exposure time control unit 51 causes the imaging unit 10 to capture an image of the interior of the vehicle V1 based on the length of the exposure time and the preset imaging frequency, which are preset by the exposure time setting unit 512. Also, in this process, the imaging control device 50 causes the imaging unit 10 to capture an image of the interior of the vehicle V1, thereby acquiring imaging information of the image of the interior of the vehicle V1. Also, in this process, the irradiation device 20 irradiates light from each of the first to fourth irradiation units 21 to 24 during the exposure time based on the preset irradiation time.

[0026] After the process of step ST2, the imaging control device 50 acquires information about the brightness of each seat of the vehicle V1 (step ST3). In this process, the brightness information acquisition unit 532 acquires information about the brightness of each seat based on the imaging information acquired in the process of step ST2.

[0027] After the process of step ST3, the imaging control device 50 detects an occupant sitting in each seat of the vehicle V1 (step ST4). For example, in this process, the occupant detection unit 52 detects the presence or absence of an occupant sitting in each seat based on the imaging information acquired in the process of step ST2.

[0028] After performing the processing of step ST4, the imaging control device 50 determines whether the brightness of each seat of the vehicle V1 is equal to or greater than the target value X set by the brightness target value setting unit 531 (step ST5). In other words, the imaging control device 50 determines whether the brightness of each seat of the vehicle V1 has reached the target value X set by the brightness target value setting unit 531. For example, the imaging control device 50 determines, by the brightness determination unit 533, whether the brightness of all seats of the vehicle V1 has reached the target value X set by the brightness target value setting unit 531. Note that in this processing, the brightness determination unit 533 may be configured to exclude seats that are already known to have no occupant from the seats for which it is determined whether the brightness has reached the target value X.

[0029] In the process of step ST5, if the brightness of all seats is equal to or greater than the target value X (YES in step ST5), the imaging control device 50 determines whether or not an occupant has been detected in each seat of the vehicle V1 in the process of step ST4 (step ST6). For example, the imaging control device 50 determines whether or not an occupant has been detected in each seat of the vehicle V1 based on the imaging information obtained by imaging by the imaging unit 10. In this process, the occupant detection unit 52 may be configured to exclude seats that are already known to have no occupant from the seats for which the presence or absence of an occupant is to be determined.

[0030] If the brightness of all seats is not equal to or greater than the target value X in the process of step ST5 (NO in step ST5), or if no occupant is detected in any seat in the process of step ST6 (NO in step ST6), the imaging control device 50 calculates the exposure time for imaging the interior of the vehicle V1 by the imaging unit 10 (step ST7). In this process, the imaging control device 50 calculates the exposure time appropriate for imaging by the imaging unit 10 based on whether the brightness of any seat does not reach the target value X or whether there is a seat in which an occupant could not be detected even though the brightness of all seats reaches the target value X. For example, in this process, the exposure time calculation unit 511 calculates, for the seat with the lowest brightness among the seats, the exposure time at which the brightness of the seat reaches the target value X when the exposure time matches the irradiation time of light by any of the first to fourth irradiation units 21 to 24 that irradiate light toward the seat.

[0031] After performing the process of step ST7, the imaging control device 50 calculates, for each seat other than the seat with the lowest brightness, the light irradiation time of each of the first to fourth irradiators 21 to 24 so that the brightness of each seat becomes the target value X (step ST8). In this process, the irradiation time calculation unit 534 calculates the light irradiation time of the first to fourth irradiators 21 to 24 so that the difference in brightness between each seat, including the seat with the lowest brightness, becomes small, using the target value X for brightness as a reference.

[0032] After performing the processing of step ST8, the imaging control device 50 determines whether or not there was a seat whose brightness reached the target value X in the processing of step ST3 (step ST9). In this processing, the brightness determination unit 533 determines whether or not there was a seat from which information indicating that the brightness was sufficient was acquired in the processing of step ST3.

[0033] In the process of step ST9, if there is a seat whose brightness has reached the target value X (YES in step ST9), the imaging control device 50 determines whether or not an occupant has been detected for each seat whose brightness has reached the target value X (step ST10). For example, in this process, the occupant detection unit 52 determines whether or not an occupant has been detected for all seats whose brightness has reached the target value X. In this process, the occupant detection unit 52 determines whether or not there was a seat in which an occupant was not detected even though the brightness was sufficient. Note that the occupant detection unit 52 may be configured to exclude seats that are already known to have no occupant before performing this process from the seats for which it is determined whether or not an occupant has been detected.

[0034] In the process of step ST10, if an occupant has not been detected in any seat whose brightness has reached the target value X (NO in step ST10), in other words, if there is a seat in which no occupant has been detected even though the brightness has reached the target value X in the process of step ST10, the imaging control device 50 shortens the light emission time of the irradiation unit that irradiates light onto the seat in which no occupant has been detected (step ST11). For example, in the process of step ST10, if there is a seat in which no occupant has been detected even though the brightness has reached the target value X, the imaging control device 50 sets to zero the light emission time of the irradiation unit that irradiates light onto the seat in which no occupant has been detected. In other words, in the process of step ST10, if there is a seat in which no occupant has been detected even though the brightness has reached the target value X, the imaging control device 50 sets to zero the irradiation time of the irradiation unit that irradiates light onto the seat in which no occupant has been detected. In this process, the irradiation time setting unit 535 stops the light emission of the irradiation unit corresponding to the seat in which no occupant has been detected even though the brightness was sufficient, thereby suppressing the amount of current consumed by the irradiation device 20.

[0035] In the process of step ST9, if there is no seat whose brightness has reached the target value X (NO in step ST9), and if the process of step ST11 has been performed, the imaging control device 50 sets the light emission time of each of the first to fourth irradiating units 21 to 24 (step ST12). In this process, the irradiation time setting unit 535 sets the irradiation time of light by each of the first to fourth irradiating units 21 to 24 calculated by the irradiation time calculation unit 534 in step ST8.

[0036] In the processing of step ST6, if occupants are detected in all seats (YES in step ST6), and if the processing of step ST12 is performed, the imaging control device 50 ends the processing. By performing the processing of steps ST1 to ST12 at a preset frequency, the imaging control device 50 repeatedly captures images of the interior of the vehicle V1, making it possible to obtain information about the occupants inside the vehicle V1.

[0037] 6 is a timing chart showing the exposure time of the imaging unit 10 and the irradiation time of each irradiation unit controlled by the imaging control device 50 according to the first embodiment. As shown in FIG. 6, the imaging control device 50 sets the length of the exposure time and the exposure start timing, and the imaging unit 10 repeatedly images the interior of the vehicle V1 at a period Tf. The imaging control device 50 also sets the irradiation time, and controls the first to fourth irradiation units 21 to 24 to irradiate light during the exposure time. In other words, the imaging control device 50 controls the first to fourth irradiators 21 to 24 so that a portion of the exposure time overlaps with the light irradiation time. In other words, the imaging control device 50 controls the first to fourth irradiators 21 to 24 so that the light irradiation time is included in the exposure time.

[0038] For example, the first to fourth irradiators 21 to 24 are controlled by the imaging control device 50 to start irradiating light in synchronization with the start timing of the exposure time and irradiate light according to the irradiation time set for each irradiator. For example, the first to fourth irradiators 21 to 24 are controlled by the imaging control device 50 to continuously irradiate light from the start of the exposure time until the irradiation time set for each irradiator has elapsed. The first to fourth irradiators 21 to 24 irradiate light for exposure time T1 and then irradiate light again for exposure time T2, which is a period Tf after the start of exposure time T1. In this way, the imaging control device 50 according to the first embodiment controls the irradiation times of the first to fourth irradiators 21 to 24 without adjusting the light intensities of the first to fourth irradiators 24, thereby enabling imaging information of sufficient brightness to be obtained by imaging by the imaging unit 10. The irradiation time setting unit 535 only needs to be configured to set the irradiation time for each irradiation unit to irradiate light during the exposure time, and in addition to setting the irradiation time so that light is irradiated continuously, it may also set the irradiation time so that a duty ratio of irradiation during the exposure time is set to perform PWM (Pulse Width Modulation) control.

[0039] Furthermore, the irradiation time setting unit 535 is configured to control the irradiation time of each irradiation unit so that at least one of the irradiation start time and irradiation end time of each irradiation unit is synchronized. This reduces the processing load of the device and enables the device to be made smaller than when the irradiation start time and irradiation end time of each irradiation unit are controlled individually.

[0040] As described above, the occupant monitoring system 100 according to the first embodiment includes an imaging unit 10 that images the driver's seat P1 and one of the rear seats different from the driver's seat P1 within the same field of view 10a, a first irradiating unit 21 that irradiates light toward the driver's seat P1, a second irradiating unit 22 that irradiates light toward one of the rear seats P2, a brightness information acquiring unit 532 that acquires information regarding the brightness of the driver's seat P1 and information regarding the brightness of one of the rear seats P2, and an irradiation time control unit 53 that controls the irradiation time of light by the first irradiating unit 21 and the second irradiating unit 22 during the exposure time T1 during which imaging is performed by the imaging unit 10, based on the information acquired by the brightness information acquiring unit 532, so as to reduce the difference in brightness between the driver's seat P1 and one of the rear seats P2.

[0041] Generally, when capturing images of the interior of a vehicle using an imaging unit such as a camera, if the brightness differs depending on the position of the occupants, it is difficult to capture images of multiple occupants within the same field of view and detect the occupants based on the image information obtained by the image capture. For example, if a light source and a camera are located closer to the driver's seat than the rear seats, the obtained image information is likely to be dark in the rear seats. When capturing images under such conditions, it is difficult to improve the accuracy of information acquisition when detecting occupants from the image information due to the difference in brightness between the driver's seat and the rear seats.

[0042] Since the occupant monitoring system 100 according to the first embodiment is configured as described above, it controls the duration of light irradiation by the multiple irradiators directed toward the imaged position based on information about the brightness of the imaged position, thereby making it possible to reduce the difference in brightness between the multiple positions and improve the accuracy of information acquisition. Furthermore, since it is possible to reduce the difference in brightness between the multiple positions in the imaged information without controlling the light intensity of the irradiators, it is possible to reduce the difference in brightness between the multiple positions in the imaged information with high accuracy compared to when the light intensity is controlled, and it is also possible to simplify the processing and reduce the size of the device.

[0043] The imaging control device 50 according to the first embodiment is configured to detect occupants inside the vehicle V1 based on imaging information obtained by imaging the interior of the vehicle V1, but is not limited to this. The imaging control device may be configured to control the irradiation times of multiple irradiation units that irradiate light toward each position based on the brightness of each position within at least the same field of view. For example, the imaging control device may not perform any detection based on imaging information, and the detection target may not be an occupant or may be something other than a person. Furthermore, the range imaged by the imaging unit does not have to be the interior of a vehicle, but may be the interior of a ship, an airplane, a railroad car, the interior of a building, or outdoors.

[0044] Embodiment 2 Next, we will explain an occupant monitoring system 200 according to embodiment 2. The occupant monitoring system 200 according to embodiment 2 differs from the occupant monitoring system 100 according to embodiment 1 in the configuration of the lighting device and part of the configuration of the imaging control device, but the other configuration is the same as the occupant monitoring system 100 according to embodiment 1. Therefore, the same names or the same reference numerals will be used to designate the same configuration as the occupant monitoring system 100 according to embodiment 1, and explanations thereof will be omitted.

[0045] Fig. 7 is a schematic plan view showing an occupant monitoring system 200 according to embodiment 2, and Fig. 8 is a block diagram showing the configuration of the occupant monitoring system 200 according to embodiment 2. As shown in Figs. 7 and 8, the occupant monitoring system 200 according to embodiment 2 includes an imaging unit 10, an irradiation device 30, and an imaging control device 60.

[0046] The illumination device 30 emits light to irradiate the interior of the vehicle V2. For example, the illumination device 30 is configured with a plurality of LEDs and receives a current to irradiate the interior of the vehicle V2 with infrared light. Furthermore, for example, the illumination device 30 has a plurality of illumination units that are arranged at different positions to emit light. Specifically, the illumination device 30 has a first illumination unit 21, a second illumination unit 32, and a third illumination unit 23, and the first illumination unit 21 to the third illumination unit 23 irradiate light toward each part of the interior of the vehicle V2. For example, the first illumination unit 21 irradiates an illumination area 21a toward the driver's seat P1 of the vehicle V2, which is a first position. The second illumination unit 32 irradiates an illumination area 32a toward one rear seat P2 and the other rear seat P4 of the vehicle V2, which are second positions. The third illumination unit 23 irradiates an illumination area 23a toward the passenger seat P3 of the vehicle V2. Furthermore, the light irradiation area 32a of the second irradiating section 32 partially overlaps with the light irradiation area 21a of the first irradiating section 21 and the light irradiation area 23a of the third irradiating section 23 in the region A1. The direct light from the first irradiating section 21, the direct light from the second irradiating section 32, and the direct light from the third irradiating section 23 overlap each other in an area A1.

[0047] In this way, when there are areas where the direct light from multiple irradiation units overlap and areas where it does not overlap, the areas where the direct light overlaps are brighter than the areas where it does not overlap, resulting in uneven brightness across the entire field of view 10a. When brightness becomes uneven within the field of view 10a, the accuracy of information acquisition through imaging information may decrease.

[0048] For this reason, the imaging control device 60 of embodiment 2 aims to improve the accuracy of information acquisition from imaging information by reducing the amount of light acquired by the imaging unit 10 from areas where direct light from multiple irradiation units overlaps with each other.

[0049] The imaging control device 60 includes an exposure time control unit 51, an occupant detection unit 52, an irradiation time control unit 53, and an imaging information correction unit 64. The imaging information correction unit 64 performs a process of reducing brightness in an area where direct light from a plurality of preset irradiation units overlaps with each other in imaging information obtained by imaging with the imaging unit 10. For example, the imaging information correction unit 64 corrects the imaging information obtained by imaging with the imaging unit 10 so as to reduce brightness in an area where direct light from a plurality of preset irradiation units overlaps with each other. The occupant detection unit 52 detects an occupant based on the imaging information whose brightness has been corrected by the imaging information correction unit 64. Furthermore, for example, the imaging information correction unit 64 corrects the imaging information so as to reduce brightness in an area where direct light from a plurality of preset irradiation units overlaps with each other in accordance with the duration of overlap of the direct light.

[0050] The hardware configuration of the imaging control device 60 according to the second embodiment is similar to the hardware configuration of the imaging control device 50 according to the first embodiment, and therefore a description thereof will be omitted.

[0051] 9 is a flowchart showing the processing performed by the imaging control device 60 according to embodiment 2. The processing performed by the imaging control device 60 according to embodiment 2 differs from the processing performed by the imaging control device 50 according to embodiment 1 in that step ST13 is performed between steps ST3 and ST4, but the other steps are the same as those of the imaging control device 50 according to embodiment 1, and therefore steps similar to those of the processing performed by the imaging control device 50 according to embodiment 1 are denoted by the same reference numerals and description thereof will be omitted.

[0052] After performing the process of step ST3, the imaging control device 60 performs an imaging information correction process to correct the imaging information obtained by imaging with the imaging unit 10 so as to reduce the brightness of an area where direct light from a plurality of preset irradiators overlaps with one another. For example, in this process, the imaging information correction unit 64, which serves as a brightness reduction unit, performs the imaging information correction process as a brightness reduction process to correct the imaging information obtained by imaging with the imaging unit 10 so as to reduce the brightness of an area A1 (see FIG. 7 ) where direct light from the first irradiator 21, the second irradiator 32, and the third irradiator 23 overlap with one another. Note that the imaging information correction unit may be configured to reduce the brightness of an area where direct light from a plurality of irradiators overlaps with one another in the imaging information obtained by imaging with the imaging unit 10. For example, the imaging information correction unit may be configured to control the imaging unit 10 so as to reduce the amount of light acquired by the imaging unit 10 from the area A1 when the imaging unit 10 performs imaging, or may be configured to thin out part of the information corresponding to the area A1 when acquiring imaging information from the imaging unit 10.

[0053] After performing the process of step ST13, the imaging control device 60 performs the process of step ST4.

[0054] 10 is a timing chart showing the exposure time of the imaging unit 10 and the irradiation time of the irradiation unit controlled by the imaging control device 60 according to embodiment 2. Similar to the imaging control device 50 according to embodiment 1, the imaging control device 60 according to embodiment 2 controls the imaging unit 10 and each irradiation unit, and causes the imaging unit 10 to repeatedly capture images of the interior of the vehicle V1 at a period Tf.

[0055] Embodiment 3 Next, an occupant monitoring system 300 according to embodiment 3 will be described. The occupant monitoring system 300 according to embodiment 3 differs from the occupant monitoring system 200 according to embodiment 2 in the processing related to the imaging information correction unit, but other configurations are similar to the occupant monitoring system 200 according to embodiment 2. Therefore, the same names or symbols are used for the same configurations as the occupant monitoring system 200 according to embodiment 2, and descriptions thereof will be omitted.

[0056] 8, an occupant monitoring system 300 according to the third embodiment includes an imaging unit 10, an irradiation device 30, and an imaging control device 70. The imaging control device 70 includes an exposure time control unit 51, an occupant detection unit 52, an irradiation time control unit 53, and an imaging information correction unit 74.

[0057] 7, when light G1 as disturbance light is incident from the outside of vehicle V2 toward interior S1 through a window of vehicle V2, the amount of light acquired by imaging unit 10 during the exposure time may become excessive depending on the intensity of light G1 and the length of time for which light G1 is incident, and the imaging information obtained by imaging may become too bright, resulting in insufficient accuracy in acquiring information from the imaging information. For this reason, exposure time calculation unit 511 according to embodiment 3 calculates the length of the exposure time by imaging unit 10 based on the information acquired by brightness information acquisition unit 532, when the brightness of any seat exceeds a preset brightness, so that the exposure time is shorter than when the brightness does not exceed the preset brightness.

[0058] 11 is a timing chart showing the exposure time of the imaging unit 10 and the irradiation time of the irradiation unit controlled by the imaging control device 70 according to Embodiment 3. For example, when the amount of light acquired by the imaging unit 10 from any seat exceeds a preset value during the exposure time, the imaging control device 70 controls the imaging unit 10 so that the exposure time for subsequent imaging is T4, which is shorter than the exposure times T1 and T2 shown in FIG. 10, which are the exposure times when the amount of light acquired from any seat does not exceed the preset value. This makes it possible to prevent the brightness of the imaging information from becoming excessive (bloated highlights) and improve the accuracy of acquiring information from the imaging information.

[0059] Furthermore, for seats where the brightness of the imaging information has decreased due to the shortened exposure time, the accuracy of acquiring information from the imaging information can be improved by partially overlapping the imaging information from multiple times, for example, two times. For example, the imaging information correcting unit 74 according to the third embodiment is configured to partially overlap the first imaging information acquired during the first exposure time T1 and the second imaging information acquired during the second exposure time T2 at a position of each seat where the brightness of the imaging information is lower than at other positions, and the occupant detection unit 52 detects an occupant within the field of view based on the overlapping information.

[0060] The hardware configuration of the imaging control device 70 according to the third embodiment is similar to the hardware configuration of the imaging control device 50 according to the first embodiment, and therefore a description thereof will be omitted.

[0061] In addition, the present disclosure allows for free combination of the respective embodiments, modification of any of the components of the respective embodiments, or omission of any of the components of the respective embodiments. [Industrial Applicability]

[0062] An imaging device according to the present disclosure can be used, for example, in an occupant monitoring system that acquires information about an occupant in a vehicle by capturing an image of the occupant.

[0063] Various aspects of the present disclosure are summarized below as appendices.

[0064] (Appendix 1) an imaging unit that images a first position and a second position different from the first position within the same field of view; a first irradiating unit that irradiates light toward the first position; a second irradiating unit that irradiates light toward the second position; a brightness information acquisition unit that acquires information about brightness at the first position and information about brightness at the second position; an irradiation time control unit that controls, based on the information acquired by the brightness information acquisition unit, irradiation times of light by the first irradiation unit and the second irradiation unit during an exposure time during which imaging is performed by the imaging unit, so that a time during which light is irradiated toward one of the first position and the second position, which has lower brightness, is longer than a time during which light is irradiated toward the other position. An imaging control device characterized by: (Appendix 2) The brightness information acquisition unit acquires information about brightness at the first position and the second position based on imaging information obtained by imaging by the imaging unit. 2. An imaging control device according to claim 1. (Appendix 3) A detection unit for detecting a specific object located within the field of view is provided. 3. An imaging control device according to claim 1 or 2. (Appendix 4) The detection unit detects a specific object within the field of view based on image information obtained by the image capture unit. 4. The imaging control device according to claim 1, wherein: (Appendix 5) the imaging unit images the first position and the second position within the same field of view during a first exposure time and a second exposure time different from the first exposure time; The detection unit detects a specific object within the field of view based on information obtained by superimposing first imaging information acquired by the imaging unit during the first exposure time and second imaging information acquired by the imaging unit during the second exposure time. 5. An imaging control device according to any one of claims 1 to 4. (Appendix 6) The detection unit detects a specific object within the field of view based on information acquired by the brightness information acquisition unit, and based on information obtained by superimposing the first image capture information and the second image capture information at a position where the brightness of the image capture information is lower between the first position and the second position. 6. An imaging control device according to any one of claims 1 to 5. (Appendix 7) When the detection unit does not detect a specific object located at one of the first position and the second position, the irradiation time control unit controls the irradiation time of light from one of the first position and the second position so that the irradiation time of light from one of the first position and the second position is shorter than when the detection unit detects a specific object. 7. An imaging control device according to any one of claims 1 to 6. (Appendix 8) The irradiation time control unit controls the irradiation times of the light by the first irradiation unit and the second irradiation unit so that at least one of the irradiation start time and the irradiation end time of the first irradiation unit and the second irradiation unit is aligned. 8. An imaging control device according to any one of claims 1 to 7. (Appendix 9) a target value acquisition unit that acquires a target value related to the amount of light acquired by the imaging unit from the first position and the second position, The irradiation time control unit controls the irradiation times of the light by the first irradiation unit and the second irradiation unit based on the information acquired by the brightness information acquisition unit so that the amount of light acquired by the imaging unit from the first position and the second position approaches the target value. 9. An imaging control device according to any one of claims 1 to 8. (Appendix 10) an exposure time control unit that controls the length of the exposure time based on the information acquired by the brightness information acquisition unit; 10. An imaging control device according to any one of claims 1 to 9. (Appendix 11) The exposure time control unit controls the length of the exposure time when the brightness of at least one of the first position and the second position exceeds a preset brightness based on the information acquired by the brightness information acquisition unit, so that the exposure time is shorter than when the brightness does not exceed the preset brightness. 11. An imaging control device according to any one of claims 1 to 10. (Appendix 12) a brightness reduction unit that performs a brightness reduction process to reduce brightness in an area where direct light from the first irradiation unit and direct light from the second irradiation unit overlap in imaging information obtained by imaging with the imaging unit; 12. An imaging control device according to any one of claims 1 to 11. (Appendix 13) The brightness reduction unit performs the brightness reduction process based on the irradiation times of the first irradiation unit and the second irradiation unit. 13. An imaging control device according to any one of claims 1 to 12. (Appendix 14) An imaging control method performed by a device including an imaging unit, a first irradiation unit, a second irradiation unit, a brightness information acquisition unit, and an irradiation time control unit, a step in which the imaging unit images a first position and a second position different from the first position within the same field of view; a step in which the first irradiating unit irradiates light toward the first position; the second irradiating unit irradiating light toward the second position; a brightness information acquisition unit acquiring information about brightness at the first position and information about brightness at the second position; and a step of controlling, by the irradiation time control unit, irradiation times of light by the first irradiation unit and the second irradiation unit during an exposure time during which imaging is performed by the imaging unit, based on the information acquired by the brightness information acquisition unit, so that a time during which light is irradiated toward one of the first position and the second position, which has lower brightness, is longer than a time during which light is irradiated toward the other position. An imaging control method comprising: [Explanation of symbols]

[0065] 10 imaging unit, 10a field of view, 20 irradiation device, 21 first irradiation unit, 21a irradiation range, 22 second irradiation unit, 22a irradiation range, 23 third irradiation unit, 23a irradiation range, 24 fourth irradiation unit, 24a irradiation range, 30 irradiation device, 32 second irradiation unit, 32a irradiation range, 50 imaging control device, 51 exposure time control unit, 52 occupant detection unit (detection unit), 53 irradiation time control unit, 60 imaging control device, 64 imaging information correction unit (brightness reduction unit), 70 imaging control device, 74 imaging information correction unit, 100 occupant monitoring system (imaging control device), 200 occupant monitoring system (imaging control device), 300 occupant monitoring system (imaging control device), 511 exposure time calculation unit, 512 exposure time setting unit, 531 brightness target value setting unit (target value acquisition unit), 532 brightness information acquisition unit, 533 Brightness determination unit, 534 irradiation time calculation unit, 535 irradiation time setting unit, A1 area, G1 light (ambient light), P1 driver's seat, P2 rear seat, P3 passenger seat, P4 rear seat, S1 interior, T1 exposure time (first exposure time), T2 exposure time (second exposure time), T4 exposure time, Tf cycle, V1 vehicle, V2 vehicle, X target value.

Claims

1. an imaging unit that images a first position and a second position different from the first position within the same field of view; a first irradiating unit that irradiates light toward the first position; a second irradiating unit that irradiates light toward the second position; a brightness information acquisition unit that acquires information about brightness at the first position and information about brightness at the second position; an irradiation time control unit that controls, based on the information acquired by the brightness information acquisition unit, irradiation times of light by the first irradiation unit and the second irradiation unit during an exposure time during which image capture is performed by the image capture unit, so that a time during which light is irradiated toward one of the first position and the second position, which has lower brightness, is longer than a time during which light is irradiated toward the other position; a detection unit that detects a specific object located within the field of view, When the detection unit does not detect a specific object located at the one of the first position and the second position having lower brightness, the irradiation time control unit controls the irradiation time of light to the one of the first position and the second position having lower brightness so that the irradiation time of light is shorter than when the detection unit detects the specific object. An imaging control device characterized by:

2. an imaging unit that images a first position and a second position different from the first position within the same field of view; a first irradiating unit that irradiates light toward the first position; a second irradiating unit that irradiates light toward the second position; a brightness information acquisition unit that acquires information about brightness at the first position and information about brightness at the second position; an irradiation time control unit that controls, based on the information acquired by the brightness information acquisition unit, irradiation times of light by the first irradiation unit and the second irradiation unit during an exposure time during which image capture is performed by the image capture unit, so that a time during which light is irradiated toward one of the first position and the second position, which has lower brightness, is longer than a time during which light is irradiated toward the other position; a brightness reduction unit that performs a brightness reduction process to reduce brightness of an area where direct light from the first irradiation unit and direct light from the second irradiation unit overlap in imaging information obtained by imaging by the imaging unit. An imaging control device characterized by:

3. The brightness information acquisition unit acquires information about brightness at the first position and the second position based on imaging information obtained by imaging by the imaging unit.

3. The imaging control device according to claim 1 or 2.

4. A detection unit for detecting a specific object located within the field of view is provided.

3. The imaging control device according to claim 2.

5. The detection unit detects a specific object within the field of view based on image information obtained by the image capture unit.

5. The imaging control device according to claim 1 or 4.

6. the imaging unit images the first position and the second position within the same field of view during a first exposure time and a second exposure time different from the first exposure time; The detection unit detects a specific object within the field of view based on information obtained by superimposing first imaging information acquired by the imaging unit during the first exposure time and second imaging information acquired by the imaging unit during the second exposure time.

6. The imaging control device according to claim 5.

7. The detection unit detects a specific object within the field of view based on information acquired by the brightness information acquisition unit, and based on information obtained by superimposing the first imaging information and the second imaging information at a position where the brightness of the imaging information is lower between the first position and the second position.

7. The imaging control device according to claim 6.

8. When the detection unit does not detect a specific object located at the one of the first position and the second position having lower brightness, the irradiation time control unit controls the irradiation time of light to the one of the first position and the second position having lower brightness so that the irradiation time of light is shorter than when the detection unit detects the specific object.

5. The imaging control device according to claim 4.

9. The irradiation time control unit controls the irradiation times of the light by the first irradiation unit and the second irradiation unit so that at least one of an irradiation start time and an irradiation end time of the first irradiation unit and the second irradiation unit is aligned.

3. The imaging control device according to claim 1 or 2.

10. a target value acquisition unit that acquires a target value related to the amount of light acquired by the imaging unit from the first position and the second position; The irradiation time control unit controls irradiation times of light by the first irradiation unit and the second irradiation unit based on the information acquired by the brightness information acquisition unit so that the amount of light acquired by the imaging unit from the first position and the second position approaches the target value.

3. The imaging control device according to claim 1 or 2.

11. an exposure time control unit that controls the length of the exposure time based on the information acquired by the brightness information acquisition unit; 3. The imaging control device according to claim 1 or 2.

12. The exposure time control unit controls the length of the exposure time when the brightness of at least one of the first position and the second position exceeds a preset brightness based on the information acquired by the brightness information acquisition unit, so that the exposure time is shorter than when the brightness does not exceed the preset brightness.

12. The imaging control device according to claim 11.

13. a brightness reduction unit that performs a brightness reduction process to reduce brightness in an area where direct light from the first irradiation unit and direct light from the second irradiation unit overlap in the imaging information obtained by imaging with the imaging unit; 2. The imaging control device according to claim 1.

14. The brightness reducing unit performs the brightness reducing process based on irradiation times of the first irradiation unit and the second irradiation unit.

14. The imaging control device according to claim 2 or 13.

15. An imaging control method performed by a device including an imaging unit, a first irradiation unit, a second irradiation unit, a brightness information acquisition unit, an irradiation time control unit, and a detection unit, the imaging unit capturing an image of a first position and a second position different from the first position within the same field of view; a step in which the first irradiating unit irradiates light toward the first position; a step in which the second irradiating unit irradiates light toward the second position; the brightness information acquisition unit acquiring information about brightness at the first position and information about brightness at the second position; the illumination time control unit controls, based on the information acquired by the brightness information acquisition unit, illumination times of the first illumination unit and the second illumination unit during an exposure time during which the imaging unit captures an image, so that a time during which light is illuminated toward one of the first position and the second position, which has lower brightness, is longer than a time during which light is illuminated toward the other position; The detection unit detects a specific object located within the field of view, When the detection unit does not detect a specific object located at the one of the first position and the second position having lower brightness, the irradiation time control unit controls the irradiation time of light to the one of the first position and the second position having lower brightness so that the irradiation time of light is shorter than when the detection unit detects the specific object. An imaging control method comprising:

Images