WO2023013108A1 - Multi-camera device - Google Patents

Abstract

Provided is a multi-camera device that makes it possible to satisfy a required distance accuracy and imaging cycle that vary with circumstance using a single multi-camera device. The present invention recognizes the outside world using a parallax found using a plurality of images obtained from an arbitrary set of two or more of a plurality of cameras and comprises an imaging timing switching unit (the synchronous/asynchronous switching unit 32) that switches the plurality of cameras between synchronous and asynchronous in accordance with a desired distance accuracy and imaging cycle and a parallax calculation unit 31 that calculates the parallax using the plurality of images and the deviation in imaging timing between the plurality of cameras.

Description

Multi-camera device

The present invention relates to a multi-camera device.

As background art in this technical field, there is Japanese Patent Application Laid-Open No. 2011-205388 (Patent Document 1). In the publication, the problem is described as "to make it possible to more easily detect the deviation of the photographing timing of the stereo camera." Images obtained by photographing the presentation signal with two left and right cameras constituting a stereo camera are input. If the frequency of the presentation signal is greater than the Nyquist frequency of the frame rate of the camera, the filtering unit 93 extracts the left and right folding signals of a specific frequency from the capture signal by filtering. The matching processing unit 94 detects the phase shift of the left and right return signals, and the shift amount calculation unit 95 detects the shift of the shooting timing of the camera from the phase shift of the return signals.".

JP 2011-205388 A

A stereo camera that measures distance by triangulation is known as a multi-camera device that detects objects and measures distance. There is a distance accuracy and a processing cycle as indicators of device performance, but these performances have a trade-off relationship.

A synchronous stereo camera that synchronizes multiple cameras and captures images at the same time has excellent distance accuracy, and an asynchronous stereo camera that captures images at different times with multiple cameras (see Patent Document 1) is characterized by excellent processing cycle. Since the required distance accuracy and processing cycle change depending on the situation, there is a problem that if only one of them is adopted, the required performance cannot be satisfied depending on the scene.

An object of the present invention is to provide a multi-camera device that can meet the required distance accuracy and imaging cycle that change according to the situation with a single multi-camera device.

In order to achieve the above object, the present invention provides a multi-camera device that recognizes the external world using parallax obtained using a plurality of images obtained from an arbitrary set of two or more of a plurality of cameras, , an imaging timing switching unit that switches between synchronization and asynchronization of the plurality of cameras according to a desired distance accuracy and imaging cycle; and a parallax calculator that calculates the parallax.

According to the present invention, it is possible to provide a multi-camera device that can satisfy the required performance by appropriately switching the synchronization and asynchronization of the cameras even when the required distance accuracy and imaging cycle change.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

FIG. 2 is an explanatory diagram showing the configuration of the multi-camera device according to the first embodiment; FIG. 1 is an explanatory diagram showing the configuration of an in-vehicle multi-camera device according to Embodiment 1. FIG. FIG. 4 is an explanatory diagram of an image processing unit according to the first embodiment; FIG. 4 is an explanatory diagram of a parallax calculation unit according to the first embodiment; FIG. 4 is an explanatory diagram of the difference in distance measurement processing between a synchronous stereo camera and an asynchronous stereo camera; FIG. 4 is an explanatory diagram of a difference in imaging cycle between a synchronous stereo camera and an asynchronous stereo camera; 4 is an explanatory diagram of a synchronous/asynchronous switching unit according to the first embodiment; FIG. FIG. 9 is an explanatory diagram of a parallax calculation unit according to the second embodiment; FIG. 9 is an explanatory diagram of a required performance calculation unit according to the second embodiment; FIG. 10 is an explanatory diagram of a required performance integrated determination unit in the second embodiment; FIG. 11 is an explanatory diagram of a case in which imaging timing is set for each camera according to the third embodiment;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Example 1]
Embodiment 1 will be described with reference to FIGS. 1 to 7. FIG.

Figure 1 shows the configuration of the multi-camera device. The multi-camera device 10 is composed of a multi-camera 12 composed of a plurality of cameras 11 , a memory 13 , a CPU 14 , an image processing section 15 and an external output section 16 . Images captured by (each camera 11 of) the multi-camera 12 are stored in the memory 13 . The image processing unit 15 performs processing such as object detection on the stored image, and the obtained result is output to the outside through the external output unit 16 .

In this embodiment, the in-vehicle multi-camera device shown in FIG. 2 will be described. The multi-camera device 10 is mounted on a vehicle (hereinafter also referred to as a vehicle) 1, captures images around the vehicle, and captures a plurality of images obtained from an arbitrary set of two or more of the plurality of cameras 11. The surroundings of the vehicle (outside world) are recognized by, for example, detecting a target object using the parallax obtained using the parallax, and the obtained information is output to the control command unit 2 as a controller. The control command unit 2 determines (operating states of) the brakes (not shown), the engine 3, the steering 4, etc., which are control means of the own vehicle, based on the input information (information on the detected target object, etc.). The vehicle 1 is controlled (acceleration/deceleration control and steering control). Since the vehicle 1 travels in various scenes such as highways and shopping streets, it is necessary to switch between synchronous and asynchronous switching according to this embodiment in order to always satisfy the required performance (more specifically, the required performance of distance accuracy and imaging cycle (processing cycle)). is necessary.

Next, the image processing unit 15 will be explained using FIG. The image processing unit 15 of this embodiment includes a parallax calculation unit 31 and a synchronous/asynchronous switching unit 32 .

First, the synchronous/asynchronous switching unit 32 determines whether the multi-camera 12 (each camera 11 of it) performs synchronous imaging or asynchronous imaging according to the required distance accuracy and imaging cycle (specifically, outputs a synchronous or asynchronous flag) (explained later). This result is transmitted to the multi-camera 12 and used to control the imaging timing of the camera 11 and to correct the parallax of the asynchronous stereo cameras in the parallax calculator 31 . That is, the synchronous/asynchronous switching unit 32 has a function as an imaging timing switching unit that switches between synchronous and asynchronous operation of the plurality of cameras 11 according to desired distance accuracy and imaging cycle.

The parallax calculation unit 31 is configured by blocks as shown in FIG. The parallax calculation unit 31 receives at least two images 1 and 2 as inputs from the multi-camera 12 in the parallax calculation processing unit 41, and executes parallax calculation processing. In the parallax calculation process, a position where the same point in image 2 is captured as to a specific point in image 1 is searched. The displacement of the coordinate positions of the points obtained as a result of the search at this time is called parallax, which is converted into distance. For the calculated parallax (distance), the parallax correction amount is calculated based on the flag (synchronization flag or asynchronous flag) indicating the synchronous/asynchronous state set in the multi-camera 12 by the synchronous/asynchronous switching unit 32 (parallax correction amount calculation The processing unit 43) and the parallax correction processing unit 42 execute the correction to obtain the final parallax.

An explanation of this parallax correction processing is shown in FIG. In the synchronous stereo camera shown in FIG. 5, the parallax is calculated for the target object 51 based on the image obtained from the left camera 52 at a certain time t and the image obtained from the right camera 53 at the same time t. . On the other hand, in the asynchronous stereo camera shown in the lower part of FIG. 5, the parallax is calculated based on the images obtained from the left camera 52 at a certain time t and the right camera 54 at a different time t+1. If the sensor or the target object is moving, the distance to the target object 51 is different when these two images are captured. 55 needs to correct the calculated parallax. In other words, it is necessary to calculate (correct) the parallax using the two images and the deviation amount of imaging timing between the left and right cameras (corresponding to the correction 55 due to time change). Since the correction includes an error, the distance accuracy of the asynchronous stereo camera is generally inferior to that of the synchronous stereo camera.

Fig. 6 shows the difference in imaging cycle at this time. When the imaging cycle of the camera is Δt, the imaging cycle of the synchronous stereo camera shown in FIG. 6 is Δt. On the other hand, in the asynchronous stereo camera, as shown in the lower part of FIG. 6, the imaging period is Δt/2 when imaging is performed with a shift of exactly half the imaging period. Since a new image cannot be obtained for the duration of the imaging cycle after an image has been obtained, the shorter the imaging cycle, the higher the responsiveness of the system. In addition, when targeting an object whose shape changes moment by moment, such as a person, the shorter the imaging cycle, the less deformation between images. The shorter the distance, the smaller the amount of movement between images, so there are advantages such as easier tracking.

Next, the synchronous/asynchronous switching unit will be explained using FIG. The synchronous/asynchronous switching unit 32 determines whether the multi-camera 12 (each camera 11 thereof) performs synchronous imaging or asynchronous imaging according to the required distance accuracy and imaging cycle. As described above, a synchronous flag is output when distance accuracy is required, and an asynchronous flag is output when a short imaging cycle is required.

First, in S71, a determination is made according to the type of target object that determines (the operating state of) the control means of the own vehicle. If the target object is a vehicle, it is assumed that there is no sudden change in behavior or shape, so a synchronous stereo camera is desirable. On the other hand, if the target object is not a vehicle (such as a pedestrian), it is assumed that there will be abrupt changes in behavior or shape, so the imaging cycle must be shortened, and an asynchronous stereo camera is desirable. Therefore, if the target object is a vehicle in S71, the process proceeds to S72, and if the target object is not a vehicle, the process proceeds to S76 to output the asynchronous flag.

Next, in S72, judgment is made based on the behavior of the own vehicle. Here, it is determined whether the vehicle is traveling straight or turning, based on vehicle information such as the steering angle. When the vehicle is traveling straight ahead, the surrounding environment is unlikely to change abruptly, but when the vehicle is turning, the direction of the sensor changes significantly, so there is a high possibility that the surrounding environment will change rapidly. A stereo camera is preferable. Therefore, if the vehicle is traveling straight in S72, the process proceeds to S73, and if the vehicle is not traveling straight (if the vehicle is turning), the process proceeds to S76 to output an asynchronous flag.

Next, in S73, determination is made using the surrounding environment based on the result of object detection. Here, it is determined whether or not there is a blind spot area around the own vehicle (in other words, whether or not there is a blind spot where an object may suddenly jump out). If there are few blind spots around the vehicle and visibility is good, the possibility of an object suddenly appearing is low. Therefore, an asynchronous stereo camera capable of shortening the imaging cycle is desirable. Therefore, in S73, if the view of the surroundings is good, the process proceeds to S74, and if the view of the surroundings is poor, the process proceeds to S76 to output an asynchronous flag.

Next, in S74, determination is made based on the travel road. Here, it is determined whether the vehicle is traveling straight ahead or turning, based on map information or the like. Estimates the vehicle's driving path using map information and the results of white line detection by sensors, determines whether the vehicle will go straight or turn for the same reason as in S72, and asynchronously when the possibility of turning is high. Switch to stereo camera. That is, if the estimated traveling road is a straight road in S74, the process proceeds to S75 to output a synchronous flag. to output

In this embodiment, a plurality of conditions are treated with the same weight, but in reality, each judgment may be weighted so that important judgments are prioritized, or each judgment is scored and the total is calculated. The score may be the final decision.

(Effect of Example 1)
A stereo camera that measures distance by triangulation is known as a multi-camera device that detects an object and measures distance. There is a distance accuracy and a processing cycle as indicators of device performance, but these performances have a trade-off relationship.

　In order to improve the accuracy of ranging, it is desirable to synchronize multiple cameras and take images at the same time to remove the effects of movement and deformation of the target object. At this time, the processing cycle of the entire device is equal to the imaging cycle of the camera alone.

On the other hand, a device that captures images at different times with multiple cameras is called an asynchronous stereo camera. In the above-mentioned Patent Document 1, "The matching processing unit 94 detects the phase shift between the left and right return signals, and the shift amount calculation unit 95 detects the shift in the shooting timing of the camera from the phase shift of the return signals." and corrects the distance measurement result by estimating the amount of deviation in the measured distance due to imaging at different times. Although the distance measurement accuracy at this time is inferior to that of a synchronous stereo camera, since images are taken at different times by a plurality of cameras, the processing cycle of the entire apparatus is shorter than the image capturing cycle of each camera.

Synchronous stereo cameras have excellent distance accuracy, while asynchronous stereo cameras have excellent processing cycle. There was a problem that the performance could not be satisfied.

The multi-camera device 10 of the present embodiment described above recognizes the external world using parallax obtained using a plurality of images obtained from an arbitrary set of two or more of a plurality of cameras. an imaging timing switching unit (synchronous/asynchronous switching unit 32) that performs synchronous/asynchronous switching of the plurality of cameras according to a desired distance accuracy and imaging cycle; and a parallax calculator 31 that calculates the parallax by using the amount of deviation in imaging timing between the cameras.

Further, the desired distance accuracy and imaging cycle are determined by the type of target object that determines the control means of the own vehicle, the presence or absence of a blind spot area around the own vehicle (whether or not there is a blind spot where a sudden jump may occur), the map It is determined by whether the own vehicle is traveling straight or turning, which is determined from at least one of information or vehicle information such as steering angle.

According to this embodiment, the multi-camera device 10 that satisfies the required performance in various scenes is realized by switching the synchronous/asynchronous mode of the multi-camera device 10 according to the required distance accuracy and processing cycle. can be done.

[Example 2]
In the first embodiment, an embodiment has been described in which synchronization and asynchronization of the camera are switched. In a second embodiment, in addition to switching between synchronous and asynchronous cameras, an embodiment will be described in which an asynchronous stereo camera smoothly changes the imaging timing deviation amount between cameras.

FIG. 8 shows an explanatory diagram of the parallax calculation unit in the second embodiment. The parallax calculation unit 31 of this embodiment includes a required performance calculation unit 81 and an imaging timing deviation amount calculation unit 82 in addition to the above-described first embodiment.

The required performance calculation unit 81 calculates the required performance that the multi-camera device 10 should satisfy (more specifically, the required performance of distance accuracy and imaging cycle). An explanatory diagram of the required performance calculation unit 81 is shown in FIG. 91, 92, 93 and 94 in FIG. 9 are required performances calculated from the same viewpoints as S71, S72, S73 and S74 in FIG. In the present embodiment, the shift amount of imaging timing is not simply switched, but is smoothly changed. Therefore, the required performance is calculated so as to change smoothly depending on the scene by scoring instead of a simple determination based on presence or absence.

The target type-based required performance calculation unit 91 calculates the required performance according to the type of the target object. For example, when considering a sensor that can determine the type of vehicle or pedestrian, pedestrians are more likely to undergo rapid changes in movement compared to vehicles. . In addition, since it is desirable that the response speed is higher as the time TTC[s] until collision is shorter, the target imaging cycle Δt_a[s] is set according to the type of target object and a table set for each TTC. Vehicles and pedestrians are used as examples of types, but a plurality of types with different possibilities of occurrence of movement changes may be added, such as trucks, which have few sudden changes in movement.

The required performance calculation unit 92 based on the blind spot information calculates the required performance so that the collision can be avoided in time when an object pops out of the blind spot. When determining the target imaging cycle Δt_b[s], n [frame] is the frame required to detect the target object and perform collision determination, z [m] is the distance to the blind spot of the target object, and v_car is the vehicle speed. [m/s], and the collision avoidable distance is z_th[m]. Since it is sufficient not to pass the collision avoidable distance between jumping out and collision avoidance judgment, the required imaging cycle is the following formula should be determined so as to satisfy At this time, if n is far away, erroneous braking can be suppressed by increasing it, and if it is nearby, the danger is high, so decreasing it will widen the allowable range of braking. You can change it.

In the required performance calculation unit 93 based on vehicle behavior, a method of linearly changing the required distance accuracy and the required imaging period according to the angular velocity ω [rad/s] of the own vehicle can be considered. The larger ω is, the more rapid the turn is, and the response speed of the sensor needs to be increased. Therefore, the target imaging cycle Δt_c[s] can be expressed by the following formula, for example. As long as the relationship is such that Δt_c becomes smaller when ω is large, other formulas or a form of referring to a table in which values corresponding to ω are stored in advance may be used.

The required performance calculation unit 94 based on the surrounding environment changes the required imaging cycle Δt_d[s] for the entire scene. For example, it receives map information of the surrounding area based on GPS information, and increases Δt_d to reduce responsiveness and improve distance accuracy because the visibility of the surrounding area is good on highways, and the visibility of the surrounding areas such as residential areas is poor and diverse. In an environment where an object is expected to pop out, Δt_d is decreased to increase responsiveness. As with the target type-based required performance calculation unit 92, three or more types of switching may be performed as long as the environment requires different required imaging cycles, in addition to highways and residential areas. Also, the above environment may be determined by scene understanding by image recognition instead of GPS.

The required performance calculated from the multiple viewpoints described above is integrated by the required performance integration determination unit 95 . If the required performance cannot be satisfied at the same time, priority is given according to the urgency of control of the own vehicle, and the items with the highest priority are integrated so as to be satisfied. FIG. 10 shows a flow chart of integration processing (that is, processing for calculating the final target imaging cycle) of the required performance integration determination unit 95 . Specifically, Δt_a and Δt_b include target objects that are supposed to collide in order to set the required imaging cycle, so it is possible to calculate the times TTC_a and TTC_b until the collision when the collision occurs. TTC_a and TTC_b are compared with a threshold value (S101, S102), and TTC_a and TTC_b are compared (S103). [s] or Δt_b[s] is adopted (S104, S105). On the other hand, if these values are equal to or greater than the thresholds, there is time to spare before collision avoidance control is performed even if an object pops out. w_a, w_b, w_c, w_d), the final requested imaging cycle (=final target imaging cycle) is calculated and adopted (S106).

From the above, the required distance accuracy and the required imaging cycle are sent to the imaging timing deviation amount calculation unit 82 (FIG. 8), and the imaging timing deviation amount calculation unit 82 calculates the imaging timing deviation amount that satisfies the received required performance. In other words, the imaging timing deviation amount calculation unit 82 has a function as an imaging timing determination unit that determines the imaging timing deviation amount between the plurality of cameras 11 according to the desired distance accuracy and imaging cycle. The calculated (determined) image pickup timing deviation amount is transmitted to the multi-camera 12 to control the image pickup timing of the camera 11, and is also sent to the parallax correction amount calculation processing unit 43 and used for the parallax correction processing in the asynchronous stereo camera. be done.

(Effect of Example 2)
The multi-camera device 10 of the present embodiment described above, instead of the imaging timing switching unit, determines the imaging timing shift amount between the plurality of cameras according to desired distance accuracy and imaging cycle. A timing determination unit (imaging timing deviation calculation unit 82) is provided. Further, the apparatus further includes a required performance calculation unit 81 that calculates a (final) required imaging cycle for determining the amount of deviation in imaging timing between the plurality of cameras.

According to the present embodiment, by smoothly changing the imaging timing deviation amount of the multi-camera device 10 in accordance with the required distance accuracy and processing cycle, it is possible to obtain characteristics that are more suitable for various scenes than in the first embodiment. A multi-camera device 10 can be realized.

[Example 3]
Embodiment 3 describes an embodiment in which the cameras of the multi-camera device are used for different purposes. In the present embodiment, an example will be described in which the multi-camera device 10 is composed of a total of three cameras, one monitoring camera and two vehicles equipped with the cameras, and the two vehicles are respectively controlled.

Fig. 11 shows an overview of the system. A base camera 111 that constitutes a monitoring camera installed in the environment takes an image at a fixed timing and transmits the image and the timing to the (in-vehicle) cameras 112 and 113 mounted on the vehicles 7 and 8 . The camera 112 mounted on the vehicle 7 traveling straight needs to detect and measure the distance from the preceding vehicle 9 far in front of the own vehicle, so the performance required for distance measurement accuracy is high. Therefore, the camera 112 takes images at the same timing as the base camera 111 and processes them as a synchronous stereo camera to satisfy the required performance. On the other hand, the camera 113 mounted on the vehicle 8 that is turning is required to have high response performance because the viewing range changes greatly depending on the time when the direction of the own vehicle changes. Therefore, by shifting the imaging timing of the camera 113 from that of the base camera 111, processing as an asynchronous stereo camera satisfies the required performance. That is, the multi-camera device 10 of the present embodiment uses the imaging timing of at least one base camera 111 among the plurality of cameras as a reference, and the cameras 112 and 113 other than the base camera 111 achieve desired distance accuracy and imaging timing for each camera. A plurality of imaging timing determination units are provided for determining the deviation amount of the imaging timing according to the cycle.

As a result, even if images are aggregated from multiple independent cameras and image processing is used for different purposes, it is possible to satisfy the performance requirements set individually for each camera.

The timing is set by communicating and synchronizing the imaging times between the cameras, and by setting the base camera 111 to fire (project) an infrared light flash at the imaging timing, and the other cameras 112 and 113 to transmit the captured images. It is conceivable to adjust the imaging timing (as a reference) using an infrared light flash reflected in the image.

(Effect of Example 3)
The multi-camera device 10 of the present embodiment described above uses the imaging timing of at least one base camera 111 among the plurality of cameras as a reference, and the cameras 112 and 113 other than the base camera 111 are set to the desired timing for each camera. An imaging timing determination unit is provided that determines the amount of deviation in imaging timing according to the distance accuracy and the imaging cycle.

Also, the base camera 111 transmits its own imaging timing and image to the cameras 112 and 113 other than the base camera 111 .

In addition, the base camera 111 emits an infrared light flash at its own imaging timing, and the cameras 112 and 113 other than the base camera 111 emit desired infrared light flashes based on the timing of the captured infrared light flash. An imaging timing determination unit is provided that determines the amount of deviation in imaging timing according to the distance accuracy and the imaging cycle.

According to this embodiment, a plurality of cameras installed for different purposes, such as a surveillance camera and an in-vehicle camera, adjust their imaging timings according to their respective purposes, so that each camera satisfies different performance requirements. multi-camera device 10 can be realized.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

In addition, each of the above configurations may be partially or wholly configured by hardware, or may be configured to be realized by executing a program on a processor. Further, the control lines and information lines indicate those considered necessary for explanation, and not all control lines and information lines are necessarily indicated on the product. In practice, it may be considered that almost all configurations are interconnected.

1: vehicle (own vehicle), 10: multi-camera device, 11: camera, 12: multi-camera, 13: memory, 14: CPU, 15: image processing unit, 16: external output unit, 31: parallax calculation unit, 32 : synchronous/asynchronous switching unit (imaging timing switching unit), 81: required performance calculating unit (second embodiment), 82: imaging timing deviation amount calculating unit (imaging timing determining unit) (second embodiment)

Claims (9)

A multi-camera device that recognizes the external world using parallax obtained using a plurality of images obtained from an arbitrary set of two or more cameras,
an imaging timing switching unit that switches between synchronization and asynchronization of the plurality of cameras according to desired distance accuracy and imaging cycle;
A multi-camera device, comprising: a parallax calculator that calculates the parallax by using the plurality of images and a shift amount of imaging timing between the plurality of cameras. The multi-camera device according to claim 1,
A multi-camera device, comprising: instead of the imaging timing switching section, an imaging timing determining section that determines an amount of deviation in imaging timing between the plurality of cameras according to desired distance accuracy and imaging cycle. A multi-camera device according to claim 2,
A multi-camera apparatus, further comprising a required performance calculation unit that calculates a required imaging cycle for determining an amount of deviation in imaging timing between the plurality of cameras. The multi-camera device according to claim 1,
A multi-camera device, wherein the desired distance accuracy and imaging cycle are determined by the type of target object that determines the control means of the own vehicle. The multi-camera device according to claim 1,
A multi-camera device, wherein the desired distance accuracy and imaging cycle are determined by the presence or absence of a blind area around the vehicle. The multi-camera device according to claim 1,
A multi-camera device, wherein the desired distance accuracy and imaging cycle are determined based on whether the vehicle is traveling straight ahead or turning, as determined from at least one of map information and vehicle information. The multi-camera device according to claim 1,
Based on the imaging timing of at least one base camera among the plurality of cameras,
A multi-camera apparatus, wherein each of the cameras other than the base camera includes an imaging timing determination unit that determines an imaging timing shift amount according to a desired distance accuracy and an imaging cycle for each camera. A multi-camera device according to claim 7,
A multi-camera apparatus, wherein the base camera transmits its own imaging timing and image to a camera other than the base camera. A multi-camera device according to claim 7,
The base camera emits an infrared light flash at its own imaging timing,
The camera other than the base camera is characterized by comprising an imaging timing determination unit that determines the deviation amount of the imaging timing according to the desired distance accuracy and imaging cycle for each camera based on the timing of the infrared light flash that is imaged. A multi-camera device.

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