Delay time measurement system and method

Abstract

A delay time measurement system and method. A processor controls a light source apparatus to operate at a preset frequency; a time synchronization apparatus receives a collection instruction from the processor, collects a valid signal of a photoelectric detection apparatus at a preset moment, and synchronously triggers an image collection apparatus to collect an image; the processor receives a display image collected by the image collection apparatus, and determines a photon capture moment of an imaging device to be tested; and the delay time of said imaging device is determined on the basis of the moment of the valid signal and the photon capture moment.

Description

Delay time detection system and method

[0001] Related applications

[0002] The present application claims priority to Chinese Patent Application No. 202411053079.4, entitled “Delay time detection system” and filed on August 2, 2024, Chinese Patent Application No. 202411053173.X, entitled “Delay time detection system and method” and filed on August 2, 2024, and Chinese Patent Application No. 202411815185.1, entitled “Delay time detection method, system and time measurement target plate” and filed on December 11, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of delay detection, and in particular, to a delay time detection system and method. BACKGROUND

[0004] A virtual reality head-mounted display device, referred to as a VR headset, displays images for the left and right eyes on two screens corresponding to the left and right eyes, respectively, and the human eye perceives stereoscopic vision in the brain after obtaining such different information. Video see-through (VST) technology is a technology that captures real-world images through a camera and fuses them into a virtual scene in real time. It is one of the key technologies in the fields of virtual reality (VR), augmented reality (AR), extended reality (XR), and mixed reality (MR).

[0005] VST technology is implemented through a VR headset, i.e., a VST mode of the VR headset. This mode captures real-time video images using the camera of the VR headset, combines the real-time video images with computer-generated images, and presents them to the user on the display screen of the VR headset. The data processing used in its implementation includes real-time video capture, image processing, scene reconstruction, and rendering display, which has a high processing complexity. Therefore, it brings VST latency to the VST mode of the VR headset, thereby affecting the user experience. Precise measurement of the VST latency of the VR headset can provide a data support basis for optimizing the delay and improving the user experience.

[0006] However, there is currently no scientific, objective, and precise measurement scheme for the VST latency of the VR headset in the industry. SUMMARY

[0007] According to various embodiments of the present application, a delay time detection system and method are provided.

[0008] The application provides a delay time detection system for realizing delay time detection of a to-be-tested imaging device, comprising a time measurement target plate, an image acquisition device, a photoelectric detection device and a processor; the time measurement target plate comprises a light source device and a time synchronization device; the time synchronization device and the image acquisition device are connected with the processor respectively; the light source device, the image acquisition device and the photoelectric detection device are connected with the time synchronization device respectively; the to-be-tested imaging device is arranged between the time measurement target plate and the image acquisition device, used for acquiring an image of the light source device and displaying the image on a display component of the to-be-tested imaging device; the image acquisition device is used for acquiring a display image comprising the display component of the to-be-tested imaging device and transmitting the display image to the processor; the photoelectric detection device is arranged in front of the display component of the to-be-tested imaging device and is used for detecting refreshing of the display component; the processor is used for controlling the light source device to operate at a preset frequency; the time synchronization device is used for receiving an acquisition instruction of the processor, starting to acquire an effective signal of the photoelectric detection device at a preset time and synchronously triggering the image acquisition device to acquire an image at the time when the effective signal is acquired; the processor is further used for receiving the display image acquired by the image acquisition device and performing image processing on the display image to determine a photon capture time of the to-be-tested imaging device; and the delay time of the to-be-tested imaging device is determined according to the time when the effective signal is acquired and the photon capture time.

[0009] The application further provides a delay time detection method, comprising the following steps: controlling a light source device to operate at a preset frequency, so that a to-be-tested imaging device acquires an image of the light source device and displays the image on a display component of the to-be-tested imaging device; starting to acquire a signal of a photoelectric detection device at a preset time, recording an effective signal time and synchronously triggering an image acquisition device to acquire a display image of the to-be-tested imaging device at the effective signal time; receiving the display image acquired by the image acquisition device and determining a photon capture time of the to-be-tested imaging device based on the display image; and determining the delay time of the to-be-tested imaging device according to the effective signal time and the photon capture time.

[0010] The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the application will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to better describe and illustrate the embodiments and / or examples of the inventions disclosed herein, reference can be made to one or more drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed inventions, the presently described embodiments and / or examples, and the best mode presently contemplated of these inventions.

[0012] Figure 1 is a schematic diagram of photons generated by a light source at 0 ms according to one embodiment.

[0013] Figure 2 is a schematic diagram of photons generated by a light source at 5 ms according to one embodiment.

[0014] Figure 3 is a schematic diagram of the time difference between the arrival time of a photon and the triggering time of a photodiode according to one embodiment.

[0015] Figure 4 is a schematic diagram of the structure of a delay time detection system according to one embodiment.

[0016] Figure 5 is a schematic diagram of the structure of a light source device according to one embodiment.

[0017] Figure 6 is a display image captured by an image capturing device according to one embodiment.

[0018] Figure 7 is a schematic diagram of the structure of a time synchronization device according to one embodiment.

[0019] Figure 8 is a schematic diagram of the structure of a photodetection device according to one embodiment.

[0020] Figure 9 is a schematic diagram of a photodetection assembly integrated in an image capturing device according to one embodiment.

[0021] Figure 10 is a schematic diagram of generating a marker light source image according to one embodiment.

[0022] Figure 11 is a marker light source image and a display image according to one embodiment.

[0023] Figure 12 is a schematic diagram of the time axis of the operation of a delay time detection system according to one embodiment.

[0024] Figure 13 is a schematic diagram of the area in which an LED light bead is in a lighting state in an image according to one embodiment.

[0025] Figure 14a is a schematic diagram of the position of a first LED light bead in a lighting state in an image according to one embodiment.

[0026] Figure 14b is a schematic diagram of the position of a first LED light bead in a lighting state in an image according to another embodiment.

[0027] Figure 14c is a schematic diagram of the position of a first LED light bead in a lighting state in an image according to yet another embodiment.

[0028] Figure 15 is a schematic diagram of the structure of a time measurement marker according to one embodiment.

[0029] Figure 16 is a schematic diagram of the application process of Mark according to one embodiment.

[0030] FIG. 17 is a schematic diagram of a region of a light source framed in an image, according to one embodiment.

[0031] FIG. 18 is a flowchart of a method of detecting latency, according to one embodiment.

[0032] FIG. 19 is a schematic diagram of an image captured by an image capture device, according to one embodiment.

[0033] FIG. 20 is a flowchart of a method of detecting latency, according to another embodiment. DETAILED DESCRIPTION

[0034] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0035] Video See-through (VST), i.e., video see-through technology, is a technology that captures images of the real world through a camera and fuses them into a virtual scene in real time. In a VR headset, the VST mode captures video streams of the real world through the camera of the VR headset, then combines these video streams with virtual content, and presents them to the user through the VR headset or other display devices. In the VST mode of the VR headset, there is a delay in the display of the VR headset, and the delay reduces the user's experience, and even causes motion sickness in the user. Therefore, accurate latency detection can help manufacturers optimize the hardware or software of the device to reduce latency. Photon-to-Photon (PTP) latency is a method for measuring the latency of a VST system. Taking a VR headset as an example, PTP latency refers to the time required for the camera of the VR headset to capture photons (light signals) of the real world, and for these light signals to be processed and presented on the display of the VR headset.

[0036] In the related art, when detecting the latency of a VR headset device, the imaging device to be tested belongs to a terminal integrated device, and the latency of the VR headset is affected by the hardware, software, and use environment, as well as the intervention of the camera exposure time, frame rate, and display screen refresh frame rate during latency detection. Therefore, the stability and accuracy of the VR headset latency detection are difficult to guarantee.

[0037] In the related art, when the VST mode of the VR head-mounted display is detected, the PTP delay is detected as the delay time. The detection of the delay time in the related art mainly includes two parts: one is the light generation end; and the other is the light detection end. The light generation end is a light source. The light detection end is a photodiode, which is fixedly installed in front of the display assembly of the VR head-mounted display, so as to detect the light signal output by the display assembly. By connecting the light generation end and the light detection end to the same industrial computer, the time difference between the light generation end and the light detection end is calculated and counted to determine the delay time of the device. However, this method does not consider the influence of VST camera exposure and screen refresh, so the measurement accuracy is not high.

[0038] In the related art, the light source and the camera of the VR head-mounted display are not strictly synchronized. The camera of the VR head-mounted display has three main processes in one event, including Reset (reset process), Exposure (exposure process) and Readout (readout process). The Reset is the initialization process of the camera, which mainly clears the charge of each pixel to ensure that there is no residual charge at the beginning of exposure, so as to avoid the influence of residual image of the previous frame on the image quality of the current frame. The Exposure is the process of capturing light signals by the camera, during which each pixel in the camera sensor receives light to accumulate charge. The Readout is the process of reading the charge of each pixel from the camera sensor, which converts the charge of each pixel into a digital signal and then transmits it to the image processor for processing and storage. After the VR head-mounted display is turned on in the VST mode, the event of the camera will continue to occur. That is, the starting time of the light source being turned on to generate photons may occur at any time of the event, which will introduce the factor of exposure time in the delay time detection, thereby affecting the accuracy of the delay time detection. Since the processes of Reset and Readout are basically instantaneous, the time used for one event can be considered as the Exposure process. For example, as shown in FIG. 1, assuming that the event of the camera of the VR head-mounted display needs 11 ms, the camera captures the photons generated by the light source at the 0th ms of the current event. At this time, the detected delay time includes the 11 ms of the entire event. As shown in FIG. 2, assuming that the event of the camera of the VR head-mounted display needs 11 ms, the camera captures the photons generated by the light source at the 5th ms of the current event. At this time, the detected delay time includes the remaining 6 ms of the event. Therefore, the influence of different exposure times on the VST delay detection result needs to be considered.

[0039] In addition, after the VR headset is powered on and enters the VST mode, the display component of the VR headset is refreshed at a fixed period, as shown in FIG. 3. The photon signals collected by the camera of the VR headset may arrive at the display component at any uncertain moment in the display component refresh period, but only at the refresh moment in the refresh period will the photons be displayed on the display component. Therefore, a time difference between the arrival of the photons at the display component and the actual display of the photons on the display component will be caused, which will greatly affect the delay time detection. For example, as shown in FIG. 3, Δt1 and Δt2 are the time differences between the arrival of the photons at the display component and the actual display of the photons on the display component in two different cases.

[0040] Based on the above, how to accurately measure the VST delay of the VR headset, that is, the PTP delay, is a problem that needs to be solved urgently.

[0041] The present application provides a delay time detection system, as shown in FIG. 4, which is used to realize the delay time detection of the imaging device to be measured. The delay time detection system comprises a time measurement target plate 100, an image acquisition device 200, a photoelectric detection device 300 and a processor 400. The time measurement target plate 100 comprises a light source device 110 and a time synchronization device 120. The time synchronization device 120, the image acquisition device 200 and the imaging device to be measured 500 are respectively connected with the processor 400. The light source device 110, the image acquisition device 200 and the photoelectric detection device 300 are respectively connected with the time synchronization device 120. The above connection can be connected in a wireless manner or in a wired manner, and the present application embodiment is not limited specifically.

[0042] The to-be-tested imaging device 500 is arranged between the time measurement target plate 100 and the image acquisition device 200. The to-be-tested imaging device 500 is used to acquire an image of the light source device 110 and display the image on a display component of the to-be-tested imaging device 500. In use, the delay time detection system arranges the to-be-tested imaging device 500 between the light source device 110 and the image acquisition device 200. The light source device 110 needs to be arranged in an imaging area of a camera of the to-be-tested imaging device 500, so as to ensure that the camera of the to-be-tested imaging device 500 can acquire a complete image of the light source device 110, and display the image of the light source device 110 on the display component of the to-be-tested imaging device 500. The to-be-tested imaging device 500 can be a VR head-mounted display, or can be any device capable of realizing a VST mode, and the embodiments of the present application are not limited specifically. The following takes the to-be-tested imaging device 500 as a VR head-mounted display as an example for illustration. Since the VR head-mounted display includes two display components corresponding to left and right eyes, the image acquisition device 200 can also be two, and can acquire images corresponding to the display components, respectively. It can be understood that the photoelectric detection device 300 can also be two, and can acquire signals corresponding to screen lighting of the display components, respectively. That is, the delay time detection system provided in the embodiments of the present application can detect delay times corresponding to two display components of left and right eyes, respectively.

[0043] The image acquisition device 200 is used to acquire a display image including a display component of the to-be-tested imaging device 500, and transmit the display image to the processor 400. The display component of the to-be-tested imaging device 500 is arranged in an imaging area of the image acquisition device 200. Taking the VR head-mounted display as an example, the image acquisition device 200 is two, and the VR head-mounted display includes a display component corresponding to a left eye and a display component corresponding to a right eye; the display component corresponding to the left eye is arranged in an imaging area of a first image acquisition device 200; and the display component corresponding to the right eye is arranged in an imaging area of a second image acquisition device 200. The display image acquired by the image acquisition device 200 includes a picture displayed by the display component. The image acquisition device 200 can be a binocular detection camera, and two cameras correspond to the display component of the left eye and the display component of the right eye, respectively. The binocular detection camera is rigidly composed of two cameras of the same type, which supports automatic or manual adjustment of gain, adjustment of exposure time, and supports hard trigger shooting. In the embodiment, the adjustment range of the gain is 0dB-20dB; and the adjustment range of the exposure time is 15us-10sec.

[0044] The photoelectric detection device 300 is arranged in front of the display component of the imaging equipment to be tested 500, and is used to detect the refresh of the display component. The photoelectric detection device 300 can be integrated in the image acquisition device 200 and arranged in front of the display component of the imaging equipment to be tested 500, so as to reduce the overall volume of the delay time detection system and make the entire delay time detection system more compact. The photoelectric detection device 300 can also be fixed on the front end of the image acquisition device 200 through a support. The arrangement position of the photoelectric detection device 300 needs to ensure that the photoelectric detection device 300 can detect the refresh of the display component of the imaging equipment to be tested 500, and the embodiment is not limited specifically. Taking the imaging equipment to be tested 500 as a VR head set and the image acquisition device 200 as a binocular camera as an example, the photoelectric detection device 300 is two, one photoelectric detection device 300 corresponds to the display component of the left eye and is used to detect the refresh of the display component of the left eye. The time synchronization device 120 collects the screen lighting signal of the display component and controls the camera corresponding to the display component of the left eye to collect the display picture including the display component of the left eye based on the screen lighting signal of the display component. The other photoelectric detection device 300 corresponds to the display component of the right eye and is used to detect the refresh of the display component of the right eye. The time synchronization device 120 collects the screen lighting signal of the display component and controls the camera corresponding to the display component of the right eye to collect the display picture including the display component of the right eye based on the screen lighting signal of the display component. The photoelectric detection device 300 includes a PD photodiode. The photodiode can convert the optical signal into an electrical signal. The frequency spectrum range that the photodiode can respond to is 400 nm-690 nm, which is slightly smaller than the visible light range 380 nm-750 nm. The response time of the photodiode is 0.09 us, and the size is compact, which can reduce the overall size of the delay time detection system. The photodiode can be used to detect the refresh and refresh cycle of the display component.

[0045] The light source device 110 comprises a plurality of light source assemblies arranged in sequence and a light source driving assembly. The light source assembly can be an LED lamp or any object capable of emitting light. The number of light source assemblies can be determined according to the delay time of the imaging device 500 to be tested, and the embodiments of the present application do not make specific limitations. Sequential arrangement can be sequential alignment from one end to the other end in one direction. For example, as shown in FIG. 5, the light source device 110 can be composed of 100 independently controllable LED lamps. The time synchronization device 120 can control the operation of the light source device 110 through the light source driving assembly. The operation of the light source device 110 can be sequentially lit from left to right or from right to left. The time synchronization device 120 can also control the frequency and brightness of the light source device 110 through the light source driving assembly to achieve the effect of a marquee. During the operation of the light source device 110, only one light source assembly is in the lit state at the same time. By adjusting the frequency of the light source device 110, the delay time detection system can detect the range of delay time. For example, if the frequency of the light source device 110 is set to 1000 Hz, the time required for 100 LED lamps to complete the display is 100 ms. At this time, the delay time range of the imaging device to be tested that can be detected is 0 ms-100 ms. If the frequency of the light source device 110 is set to 300 Hz, the time required for 100 LED lamps to complete the display is 333 ms. At this time, the delay time range of the imaging device to be tested that can be detected is 0 ms-333 ms. If the frequency of the light source device 110 is set to 3000 Hz, the time required for 100 LED lamps to complete the display is 33 ms. At this time, the delay time range of the imaging device to be tested that can be detected is 0 ms-33 ms.

[0046] As shown in FIG. 4, the two photoelectric detection devices 300 are respectively integrated in the two cameras of the image acquisition device 200, or are respectively installed in front of the left and right cameras of the image acquisition device 200 and are fixed firmly. The fixing can be fixed by a fixing support (not shown in the figure) or the like. The distance between the photoelectric detection device 300 and the display component of the imaging device 500 to be measured is about 12-22 mm. The photoelectric detection device 300 is connected with the time synchronization device 120, and the time synchronization device 120 is connected with the processor 400. The photoelectric detection device 300 detects the refresh of the display component, collects the signal of the screen lighting of the display component, and sends the signal representing the screen lighting of the display component to the time synchronization device 120. The time synchronization device 120 controls the image acquisition device 200 to collect the display image including the display component of the imaging device 500 to be measured according to the signal. The image acquisition device 200 is rigidly composed of two types of binocular cameras which are completely consistent, and is connected with the processor 400. The processor 400 can set the exposure time, gain and shooting properties of the image acquisition device 200. The light source device 110, the image acquisition device 200, the photoelectric detection device 300 and the time synchronization device 120 share the same clock source, so that the delay time detection system can reach the synchronization accuracy of microsecond level.

[0047] In the use of the delay time detection system, when the delay time of the imaging device 500 to be tested is detected. First, the processor 400 is used to control the light source device 110 to operate at a preset frequency. And control the imaging device 500 to be tested to operate, wherein the control of the imaging device 500 to be tested to operate can be that the imaging device 500 to be tested is connected with the processor 400, and the imaging device 500 to be tested is controlled to operate through the processor 400, or the imaging device 500 to be tested is triggered to start operating by itself. The embodiment is not limited specifically, and only the imaging device 500 to be tested starts to operate. The control of the imaging device 500 to be tested to operate, that is, the control of the imaging device 500 to be tested to start and enter the VST mode, after entering the VST mode, the event of the camera of the imaging device 500 to be tested will continue to occur. The camera of the imaging device 500 to be tested has three main processes of Reset, Exposure and Readout in one event. Among them, Reset is the initialization process of the camera, mainly to clear the charge of each pixel, to ensure that there is no residual charge at the beginning of exposure, so as to avoid the influence of residual image of the previous frame on the image quality of the current frame. Exposure is the process of capturing light signal by the camera, during which each pixel in the camera sensor will receive light to accumulate charge. Readout is the process of reading the charge of each pixel from the camera sensor, converting the charge of each pixel into a digital signal, and then transmitting it to the image processor for processing and storage. The processor 400 controls the light source device 110 to operate at a preset frequency through the time synchronization device 120. Control the light source device 110 to operate, that is, control the light source device 110 to start, after starting, the multiple light source components of the light source device 110 are lit in turn, and only one light source component is in the state of lighting at the same time. The following is described by taking the example that after the light source device 110 operates, all the light source components are lit in turn from left to right. In the case that the delay order of magnitude of the imaging device 500 to be tested is known, the preset frequency can be determined according to the delay order of magnitude of the imaging device 500 to be tested. When the delay order of magnitude of the imaging device 500 to be tested is unknown, the frequency of the light source device 110 can be gradually approached from small to large to determine the preset frequency. When the light source device 110 is controlled to operate, the brightness of the light source device 110 is also set. The brightness needs to be set according to the brightness of the current test environment, and needs to be ensured that the light source device 110 observed in the display image collected from the image acquisition device 200 is not too bright or too dark. The processor 400 can be any device with data processing function, such as computer equipment and the like. The time synchronization device 120 can be any device with data processing function, such as single-chip microcomputer, computer equipment and the like.

[0048] After the imaging device 500 to be measured and the light source device 110 are running, the time synchronization device 120 receives the acquisition instruction of the processor 400, starts to acquire the effective signal of the photoelectric detection device 300 at the preset time T1, and synchronously triggers the image acquisition device 200 to acquire the image at the time T2 when the effective signal is acquired. The processor 400 sends the acquisition instruction to the time synchronization device 120, wherein the acquisition instruction includes the preset time T1. After receiving the acquisition instruction, the time synchronization device 120 starts to acquire the signal of the photoelectric detection device 300 at the preset time T1. After the imaging device 500 to be measured and the light source device 110 are running, the photoelectric detection device 300 is also in a working state, and the refreshing generation signal of the display assembly of the imaging device 500 to be measured is detected in real time, but the time synchronization device 120 does not acquire the signal. After the time synchronization device 120 receives the acquisition instruction, the signal of the photoelectric detection device 300 is acquired in real time at the preset time T1, and the time T2 when the effective signal is acquired is recorded and transmitted to the processor 400. The preset time T1 is determined by taking the time when the first light source assembly of the light source device 110 is lit as the initial time after the light source device 110 is running. After the light source device 110 is running, the time when the first light source assembly of the light source device 110 is lit is taken as the 0 time, and when the preset time T1 is reached, the time synchronization device 120 starts to acquire the signal of the photoelectric detection device 300. The preset time T1 needs to be set according to the delay order of magnitude of the imaging device 500 to be measured. Specifically, the preset time T1 is greater than the nominal delay of the imaging device 500 to be measured and less than or equal to the maximum delay measurement range of the light source device 110 at the preset frequency. The preset time T1 needs to be greater than the nominal delay of the imaging device 500 to be measured. If it is less than the nominal delay of the imaging device 500 to be measured, the display image acquired by the image acquisition device 200 may not be able to observe the lighted light source assembly. The nominal delay can be the delay calibrated by the imaging device to be measured when it is shipped. The maximum delay measurement range of the light source device 110 at the preset frequency is the time required for all light source assemblies to be lit in turn at the current preset frequency. For example, if the preset frequency of the light source device 110 is 1000 Hz, the light source device includes 100 light source assemblies, and the maximum delay measurement range of the light source device 110 is 100 ms. If the preset frequency of the light source device 110 is 300 Hz, the light source device includes 100 light source assemblies, and the maximum delay measurement range of the light source device 110 is 333 ms. If the preset frequency of the light source device 110 is 3000 Hz, the light source device includes 100 light source assemblies, and the maximum delay measurement range of the light source device 110 is 33 ms. For example, if the nominal delay of the imaging device 500 to be measured is 2 ms and the preset frequency of the light source device 110 is 1000 Hz, the preset time can be set to 3 ms, and the preset time T1 is the lighting time of the fourth light source assembly.In order to satisfy all the delay time corresponding to the imaging device 500 to be tested, the lighting time of the last light source component of the light source device 110 can be used as the preset time T1. Assuming that the frequency of the light source device 110 is 1000 Hz, 99 ms can be used as the preset time, that is, the lighting time of the last light source component in the light source device 110. The photoelectric detection device 300 detects the refresh of the display component of the imaging device 500 to be tested, and the time synchronization device 120 records the time T2 when the photoelectric detection device 300 detects the valid signal of the display component. Two points need to be explained here, which are as follows: (1) the valid signal represents the signal when the screen of the display component is lit; (2) the signal of the photoelectric detection device 300 corresponds to a corresponding time stamp, which can be directly recorded to the time of the valid signal through the time stamp when the photoelectric detection device 300 detects the valid signal; or the time difference between the preset time and the time when the valid signal is collected can be obtained by starting to calculate at the preset time, and then the time difference between the preset time and the time when the valid signal is collected is summed up to determine the time of the valid signal. The time synchronization device 120 synchronously triggers the control image acquisition device 200 to collect images at the time when the valid signal is collected, and the image acquisition device 200 transmits the collected display image to the processor 400.

[0049] The image acquisition device 200 acquires a display image including the display of the display component of the imaging device 500 under the condition that the time synchronization device 120 triggers the acquisition of the image at the time T2 when the valid signal is acquired. The image acquisition device 200 transmits the acquired display image to the processor 400. The display component of the imaging device 500 is within the imaging range of the image acquisition device 200, that is, the image acquisition device 200 can acquire the current display of the display component. As shown in FIG. 6, the display image acquired by the image acquisition device 200. After the light source device 110 is running, all the light source components are sequentially lit one by one. Since the imaging device 500 enters the VST mode, the event event continues to occur, and one event event lasts for a period of time, that is, the camera can continuously receive the photons generated by the light source device 110 within the period of time. If multiple light source components are sequentially lit one by one within the period of time, the camera can receive the photon signals generated by each light source component that is lit within the event event, that is, multiple light source components are lit simultaneously in the image generated by the event event. Taking an event event of 11 ms and a frequency of the light source device 110 of 1000 Hz as an example: 11 light source components are sequentially lit corresponding to one event event, so that in the image generated by the event event, the 11 light source components are in the lit state. At this time, the image acquisition device 200 acquires the display image including the display component of the imaging device 500, and the display image also includes the 11 light source components in the lit state.

[0050] After the image acquisition device 200 transmits the acquired display image to the processor 400, the processor 400 receives the display image acquired by the image acquisition device 200 and performs image processing on the display image to determine the photon capture time T3 of the imaging device 500. According to the time T2 when the valid signal is acquired and the photon capture time T3, the delay time of the imaging device 500 is determined. The processor 400 also receives the time T2 of the valid signal transmitted by the time synchronization device 120. The time T2 of the valid signal represents the time corresponding to the signal of the screen of the display component being lit, that is, the time when the display component of the imaging device 500 displays the photons. According to the display image, the photon capture time T3 of the imaging device 500 can be determined. Thus, according to the time T2 of the valid signal and the photon capture time T3, the delay time of the imaging device 500 is determined, that is, the PTP delay of the imaging device 500 is determined.

[0051] The above delay time detection system is used for realizing delay time detection of the imaging device to be detected, wherein the delay time detection system comprises a time measurement target plate, an image acquisition device, a photoelectric detection device and a processor. The time measurement target plate comprises a light source device and a time synchronization device. The time synchronization device and the image acquisition device are connected with the processor respectively. The light source device, the image acquisition device and the photoelectric detection device are connected with the time synchronization device respectively. The imaging device to be detected is arranged between the time measurement target plate and the image acquisition device, used for acquiring an image of the light source device and displaying the image on a display assembly of the imaging device to be detected. The image acquisition device is used for acquiring a display image comprising the display assembly of the imaging device to be detected and transmitting the display image to the processor. The photoelectric detection device is arranged in front of the display assembly of the imaging device to be detected, used for detecting refreshing of the display assembly. The processor is used for controlling the light source device to operate at a preset frequency. The time synchronization device is used for receiving an acquisition instruction of the processor, starting to acquire an effective signal of the photoelectric detection device at a preset time and synchronously triggering the image acquisition device to acquire an image at a time when the effective signal is acquired. The processor is further used for receiving the display image acquired by the image acquisition device and performing image processing on the display image to determine a photon capture time of the imaging device to be detected. The delay time of the imaging device to be detected is determined according to the time when the effective signal is acquired and the photon capture time. The above delay time detection system can accurately detect the delay time of the imaging device to be detected, and further improves the accuracy of delay time detection.

[0052] In one embodiment, as shown in FIG. 7, the time synchronization device 120 comprises a control module 121, a time synchronization module 122, an imaging triggering module 123 and a signal detection processing module 124. The time synchronization module 122, the imaging triggering module 123 and the signal detection processing module 124 are connected with the control module 121 respectively. The control module 121 can be any device with data processing function, such as a single-chip microcomputer, a computer device, etc. The following takes the single-chip microcomputer as an example to illustrate that the time synchronization module 122, the imaging triggering module 123 and the signal detection processing module 124 can be different pins of the single-chip microcomputer, or different pins and peripheral circuits connected with the corresponding pins. The control module 121 is used for receiving signals and transmitting the signals to the control module 121, or sending signals to external devices based on instructions of the control module 121.

[0053] The time synchronization module 122 is connected with the image acquisition device, the photoelectric detection device and the light source device respectively, and is used for controlling clock synchronization of the image acquisition device, the photoelectric detection device and the light source device. The time synchronization module 122 can be a clock source, and the time synchronization module 122 synchronizes clocks of the image acquisition device, the photoelectric detection device and the light source device with a clock source of the time synchronization module 122, so as to ensure clock synchronization of the delay time detection system, avoid errors caused by inconsistent clocks in the system, and further improve accuracy of delay time detection.

[0054] The control module 121 is connected with the processor, and is used for receiving an acquisition instruction of the processor and starting to acquire a signal of the photoelectric detection device through the signal detection processing module 124 at the preset time T1. The control module 121 receives the acquisition instruction of the processor, and starts to acquire the signal of the photoelectric detection device through the signal detection processing module 124 at the preset time T1 after receiving the acquisition instruction.

[0055] The signal detection processing module 124 is connected with the photoelectric detection device, and is used for acquiring a signal of the photoelectric detection device, determining an effective signal, and transmitting the effective signal to the control module 121. The signal detection processing module 124 can be a pin of the control module 121, or can include a signal detection circuit connected with the pin, and is used for acquiring the signal of the photoelectric detection device, determining the effective signal in the signal of the photoelectric detection device, and transmitting the effective signal to the control module 121. The effective signal is a signal when a screen of the display assembly is lighted. For example, the effective signal can be a high-level signal or a rising edge signal, and the embodiment is not limited in this regard.

[0056] The control module 121 is also used for recording a time T2 when the effective signal is acquired, triggering the image acquisition device to acquire an image through the imaging trigger module 123 at the time T2 when the effective signal is acquired, and transmitting the time when the effective signal is acquired to the processor. After receiving the effective signal, the control module 121 records the time T2 when the effective signal is acquired, triggers the image acquisition device to acquire an image through the imaging trigger module 123, and transmits the time T2 when the effective signal is acquired to the processor.

[0057] The imaging trigger module 123 is connected with the image acquisition device, and is used for triggering the image acquisition device to acquire an image based on an instruction of the control module 121. The imaging trigger module 123 can be a pin of the control module 121, or can include a signal transmission circuit connected with the pin, and is used for triggering the image acquisition device to acquire an image at the time when the control module 121 acquires the effective signal.

[0058] In the embodiment of the present application, the time synchronization device comprises a control module, a time synchronization module, an imaging trigger module and a signal detection processing module; the control module is connected with the time synchronization module, the imaging trigger module and the signal detection processing module respectively, so as to improve the data processing speed of the control module, complete the time synchronization of the system through the time synchronization module, collect the signal of the photoelectric detection device through the signal detection processing module, trigger the image acquisition device to collect images through the imaging trigger module, and further improve the data processing efficiency of the control module. By setting the signal detection processing module, the problem that the related art does not detect the refresh of the display component when detecting the delay time, resulting in large test result error and low repeatability is solved.

[0059] In one embodiment, as shown in FIG. 7, the time synchronization device further comprises a timer 125; the timer 125 is connected with the control module 121. The control module 121 is further configured to receive a running instruction of the processor and transmit the running instruction to the timer 125; the timer 125 is configured to start timing based on the running instruction and transmit timing information to the control module 121; the control module 121 is further configured to start collecting the signal of the photoelectric detection device through the signal detection processing module 124 at a preset time T1 based on the timing information, and record the time T2 when the valid signal is collected based on the timing information. When the processor controls the light source device to run at a preset frequency, the processor generates a running instruction and transmits the running instruction to the time synchronization device, i.e., to the control module 121; the control module 121 controls the light source device to run at a preset frequency according to the running instruction, and synchronously transmits the running instruction to the timer 125; after receiving the running instruction, the timer 125 starts timing from 0 and transmits the timing information of the timer 125 to the control module 121 in real time. The control module 121 can receive the timing information of the timer 125 in real time; after receiving the collection instruction of the processor, the control module 121 starts collecting the signal of the photoelectric detection device through the signal detection processing module 124 when the timing signal reaches the preset time T1 based on the timing information. When the valid signal is collected, the current time is determined according to the timing information, and the current time is recorded as the time T2 when the valid signal is collected.

[0060] By setting the timer, the time reference of the preset time T1 and the time T2 when the valid signal is collected is ensured, and the accuracy of the delay time detection is further improved.

[0061] In one of the embodiments, a first type of time measurement calibration board is provided. Specifically, the light source device comprises a plurality of light source assemblies arranged in sequence and a light source driving assembly; the light source driving assembly is connected with the plurality of light source assemblies and a time synchronization device. The light source driving assembly is connected with the control module of the time synchronization device. The time synchronization device is also used to receive the running instruction of the processor and control the light source driving assembly to light up the plurality of light source assemblies at a preset frequency. That is, the control module is used to receive the running instruction of the processor and control the light source driving assembly to light up the plurality of light source assemblies at a preset frequency. The light source assembly can be an LED, which can be an LED of different colors and different shapes. The plurality of light source assemblies can be arranged in a row, a column or a ring, as long as the calculation of the photon capture moment is met. For example, the light source device comprises 100 LEDs arranged horizontally. The light source driving assembly is used to drive the light source device to run, wherein one light source driving can be arranged to drive the plurality of light source assemblies to run, or the plurality of light source assemblies can be independently driven, that is, an independent driving is arranged for each light source assembly. The specific driving mode is not limited in the embodiment. The processor generates a running instruction when controlling the light source device to run at a preset frequency, the running instruction comprises the preset frequency, and the running instruction is transmitted to the time synchronization device, that is, to the control module. The control module sends the running instruction to the light source driving assembly, and the light source driving assembly generates a driving signal corresponding to the preset frequency. The light source driving assembly lights up the plurality of light source assemblies at a preset frequency according to the driving signal.

[0062] In one of the embodiments, the time synchronization device is also used to control the light source driving assembly to light up the plurality of light source assemblies at a preset frequency.

[0063] The multiple light source assemblies are lighted at the preset frequency, any one of the multiple light source assemblies can be the first lighted light source assembly, and the subsequent light source assemblies are lighted in turn. The time synchronization device can also control the light source driving assembly to light the multiple light source assemblies in turn at the preset frequency, that is, the first light source assembly of the multiple light source assemblies is the first light source assembly, and the subsequent light source assemblies are lighted in turn. For example, the light source device includes 100 LEDs arranged horizontally. One LED can be lighted at a time, and the LEDs are lighted in turn from left to right, or one LED can be lighted at a time, and the LEDs are lighted in turn from right to left. Taking the light source assemblies lighted in turn from left to right as an example, the 50th LED can be the first lighted light source assembly, and the subsequent light source assemblies are lighted in turn at the preset frequency, or the 1st LED can be the first lighted light source assembly, and the subsequent light source assemblies are lighted in turn at the preset frequency. The multiple light source assemblies arranged horizontally can reduce the number of adjacent light source assemblies, thereby reducing the influence between the light source assemblies. The multiple light source assemblies are lighted in turn at the preset frequency, which can provide a time reference for the measurement of the delay time, thereby making the detection of the delay time more accurate.

[0064] In one embodiment, as shown in FIG. 8, the photoelectric detection device 300 includes a photoelectric detection assembly 310 and a post-processing circuit 320. The photoelectric detection assembly 310 is connected with the post-processing circuit 320, and is used to detect the refresh of the display assembly, generate a photoelectric current signal, and transmit the photoelectric current signal to the post-processing circuit 320. The post-processing circuit 320 is connected with the time synchronization device 120, and is used to convert the photoelectric current signal into a voltage signal, and transmit the voltage signal to the time synchronization device 120. The photoelectric detection assembly 310 can be a photodiode, and the photoelectric detection assembly 310 detects the refresh of the display assembly of the imaging device to be tested, and converts the light signal into a photoelectric current signal. After receiving the photoelectric current signal, the post-processing circuit 320 converts the photoelectric current into a voltage signal, and transmits the voltage signal to the time synchronization device 120, that is, to the signal detection processing module 124. The voltage signal is also the signal of the photoelectric detection device.

[0065] The post-processing circuit 320 comprises a gain adaptive circuit 321 connected with the photodetection assembly 310 and the time synchronization device 120, for converting the photocurrent signal into a voltage signal based on a preset gain, and transmitting the voltage signal to the time synchronization device 120. The preset gain is a preset amplification multiple, and the gain adaptive circuit 321 converts the photocurrent signal into the voltage signal based on the preset gain, and transmits the voltage signal to the time synchronization device 120. Since the current induced by the photodiode is very weak, only nA level, that is, the photocurrent signal is very weak and cannot be recognized by the time synchronization device 120, the photocurrent signal needs to be amplified before subsequent signal processing. Therefore, the preset gain is set to convert the photocurrent signal into the voltage signal. The size of the preset gain can be set according to the actual use scene. If the preset gain is too small, the voltage signal cannot be generated. If the gain is too large, some dark current will be amplified, which will interfere with the voltage signal. The gain adaptive circuit 321 can comprise an operational amplifier.

[0066] In the embodiment, by setting a suitable preset gain, the time synchronization device 120 can detect a clearer effective signal, and the influence of the interference signal can be better eliminated.

[0067] In one of the embodiments, the post-processing circuit 320 further comprises a false trigger circuit 322 connected between the gain adaptive circuit 321 and the time synchronization device 120, for filtering the voltage signal based on a preset voltage threshold, and transmitting the filtered voltage signal to the time synchronization device 120. In order to further prevent the interference signal from affecting the recognition of the effective signal, the false trigger circuit 322 can be set before the gain adaptive circuit 321 transmits the voltage signal to the time synchronization device 120. The false trigger circuit 322 filters the interference voltage of the preset voltage threshold from the voltage signal, and then transmits the filtered voltage signal to the time synchronization device 120, so as to further ensure the accurate recognition of the effective signal and improve the detection accuracy of the delay time. The preset voltage threshold can be a plurality of voltage values or a voltage range. It can be understood that the voltage corresponding to the interference signal is lower than the voltage corresponding to the effective signal. In order to ensure accurate recognition of the effective signal, the voltage lower than the effective signal can be filtered out. For example, assuming that the voltage of the effective signal to be recognized is 5V, the preset voltage can be set to be less than 5V, so that the false trigger circuit 322 filters out the voltage less than 5V from the voltage signal, and retains the effective signal of 5V.

[0068] In one of the embodiments, the time synchronization device 120 is connected with the gain adaptive circuit 321, and the time synchronization device 120 is further configured to collect the voltage signal of the gain adaptive circuit 321 before the preset time, determine the frequency parameter and the voltage parameter of the voltage signal, and generate a gain adjustment signal based on the frequency parameter or the voltage parameter, and transmit the gain adjustment signal to the gain adaptive circuit 321. The gain adaptive circuit 321 is further configured to adjust the preset gain according to the gain adjustment signal. Since there are differences in display brightness of display components of different VR headsets, in order to adapt to VR headsets with different display brightness, the time synchronization device 120 can also adaptively adjust the preset gain according to the display brightness. The adaptive adjustment of the preset gain is before the preset time T1. If the adaptive adjustment of the preset gain is not performed, the time synchronization device 120 does not need to obtain the signal of the photoelectric detection device before the preset time T1. When the adaptive adjustment of the preset gain is needed, the signal detection processing module collects the voltage signal of the gain adaptive circuit 321 before the preset time T1, and transmits the voltage signal to the control module. The control module determines the frequency parameter and the voltage parameter of the voltage signal according to the received voltage signal, and generates a gain adjustment signal based on the frequency parameter or the voltage parameter. The gain adjustment signal can be generated according to the frequency signal alone, the gain adjustment signal can be generated according to the voltage signal alone, or the gain adjustment signal can be generated by taking into account both the frequency signal and the voltage signal. Since the refresh frequency of the display component of the VR headset is known, when the frequency of the voltage signal is greater than the known refresh frequency of the display component, it indicates that there is a voltage interference signal, and therefore the preset gain needs to be reduced. When the frequency of the voltage signal is less than the known refresh frequency of the display component, it indicates that the gain is too small, and the preset gain needs to be increased. For example, the refresh frequency of the display component of the VR headset is 90 Hz, when the frequency of the voltage signal is 1 kHz, it indicates that there is an external interference such as dark current, and a gain adjustment signal for reducing the preset gain is generated. When the frequency of the voltage signal is 10 Hz, a gain adjustment signal for increasing the preset gain is generated. Since the voltage of the effective signal is known, when the voltage of the voltage signal is greater than the voltage of the effective signal, it indicates that the amplification factor is too large, and a gain adjustment signal for reducing the preset gain needs to be generated. When the voltage of the voltage signal is less than the voltage of the effective signal, it indicates that the amplification factor is too small, and a gain adjustment signal for increasing the preset gain needs to be generated. It can be understood that the gain adjustment signal can also be generated by taking into account both the frequency parameter and the voltage parameter. After the control device generates the gain adjustment signal, the gain adjustment signal is transmitted to the gain adaptive circuit 321 through the signal detection processing module, and the gain adaptive circuit 321 reduces or increases the preset gain according to the gain adjustment signal.

[0069] The time synchronization device 120 adaptively adjusts the preset gain of the gain adaptive circuit 321, so that the delay time detection system is applicable to VR headsets with different display brightness, the test efficiency and test accuracy of the delay time are improved, and the compatibility of the delay time detection system with detection equipment is further improved.

[0070] Due to different manufacturers and backgrounds, there are display component brightness difference problems in VR headsets. The current related technology cannot be compatible with testing VR headsets with different brightness. Most VR headsets on the market have the function of adaptively adjusting the brightness of the display component to the ambient light. When the ambient light is dark, the screen brightness of the display component is low, so that the photoelectric detection device cannot detect the refresh of the display component. At this time, the brightness of the display component needs to be manually adjusted to meet the refresh detection of the photoelectric detection device by changing the ambient brightness or turning off the adaptive ambient light function. The scheme has a high test failure rate, and re-adjusting the brightness of the display component leads to low test efficiency. In the embodiment of the present application, the gain adaptive circuit can adapt to a wider range of display component brightness, has low requirements for ambient light, does not trigger false, and does not need to manually adjust the brightness of the display component, thereby improving the test efficiency and reducing the test failure rate. The false trigger circuit compares the voltage range to filter out false trigger signals, effectively avoiding false triggering problems.

[0071] In one embodiment, as shown in FIG. 9, the photoelectric detection component 310 is integrated in the image acquisition device. The image acquisition device can be a binocular camera, and the photoelectric detection component 310 can be integrated in the lens of the camera, so that the space between the camera lens and the imaging device to be tested is not occupied, and the eye relief is convenient to adjust. For example, the photoelectric detection component 310 can be integrated at the edge of the lens to avoid affecting the camera to collect the display image. Alternatively, the photoelectric detection component is arranged at the lower middle part of the image acquisition device, that is, the photoelectric detection component 310 can be integrated at the center position of the lower edge of the lens. The photoelectric detection component 310 is integrated in the image acquisition device and is fixed at the center position of the lower edge of the lens by a snap ring. At this time, the post-processing circuit 320 can be integrated with the photoelectric detection component in the image acquisition device, or the photoelectric detection component 310 and the post-processing circuit 320 can be separately arranged, and the post-processing circuit 320 is arranged on the structure and fixed on the support of the image acquisition device by the structure. The post-processing circuit 320 is connected with the photoelectric detection component 310 through a flexible flat cable (FPC) or an extremely thin coaxial cable.

[0072] In the embodiments of the present application, the photoelectric detection assembly and the post-processing circuit are designed to be separated in structure, and the photoelectric detection assembly is embedded in the lens of the image acquisition device by using a flexible flat cable, so as to not occupy the space between the camera lens and the imaging equipment to be measured, and to facilitate the adjustment of the eye distance. The photoelectric detection assembly is placed at the center of the lower edge of the lens, so that the center of the display assembly of the VR head-mounted display can be detected, and the image loss of the captured image is reduced, even if the brightness around the display assembly is low. The photoelectric detection assembly is connected to the post-processing circuit through a soft and hard combination board or an extremely thin coaxial line, so that the post-processing circuit can be placed at any position near the image acquisition device.

[0073] In one of the embodiments, the photoelectric detection device is fixedly arranged between the image acquisition device and the imaging equipment to be measured. At this time, the relative position between the photoelectric detection assembly and the image acquisition device can be that the photoelectric detection assembly is arranged at the middle of the lower end of the image acquisition device, that is, the photoelectric detection assembly is fixed on the outside of the lens of the image acquisition device by a support, and at the center of the lower edge of the lens. Thus, the influence of the photoelectric detection device on the image acquisition device is avoided, and the image quality of the image acquisition device is further improved.

[0074] In one of the embodiments, in the case where the delay magnitude of the imaging equipment to be measured is known, the preset frequency can be determined according to the delay magnitude of the imaging equipment to be measured. When the processor controls the light source device to operate at the preset frequency, the delay magnitude of the imaging equipment to be measured needs to be acquired first, the preset frequency of the light source device is determined according to the delay magnitude, and the light source device is controlled to operate at the preset frequency. The delay magnitude is a range in which the delay time of the imaging equipment to be measured can be located. For example, the delay magnitude can include 0ms-33ms, 34ms-100ms, and 101ms-333ms. A mapping relationship between the delay magnitude and the preset frequency is established in advance, after the delay magnitude of the imaging equipment to be measured is acquired, the mapping relationship is searched according to the delay magnitude, and thus the preset frequency of the light source device is determined. For example, when the delay magnitude of the imaging equipment to be measured is 0ms-33ms, the corresponding preset frequency is 3000Hz; when the delay magnitude of the imaging equipment to be measured is 34ms-100ms, the corresponding preset frequency is 1000Hz; and when the delay magnitude of the imaging equipment to be measured is 101ms-333ms, the corresponding preset frequency is 300Hz. Since the delay time of the common VR head-mounted display is within 100ms, the preset frequency of the light source device is usually set to 1000Hz, which can meet the test requirements. After the preset frequency of the light source device is determined, the processor generates an operation instruction based on the preset frequency, and transmits the operation instruction to the control module, and the control module sequentially lights up the plurality of light source assemblies at the preset frequency based on the operation instruction.

[0075] In one of the embodiments, in the case where the delay magnitude of the imaging device to be tested is unknown, the frequency of the light source assembly can be determined in a step-by-step approximation manner from small to large to determine the preset frequency. When the processor controls the light source device to operate at the preset frequency, the processor first controls the light source device to operate at the minimum frequency; acquires the first image collected by the image collection device, and if it is detected that the light source assembly is in the lighting state in the first image, the frequency is increased by a preset step, and the light source device is controlled to operate at the increased frequency; acquires the second image collected by the image collection device, and if it is detected that the light source assembly is in the lighting state in the second image, the frequency is continuously increased by the preset step until it is detected that there is no light source assembly in the lighting state in the image collected by the image collection device, and then the frequency of the previous time is taken as the preset frequency. The processor first controls the imaging device to be tested to operate and enter the VST mode, generates an operation instruction based on the minimum frequency, and transmits the operation instruction to the control module, and the control module sequentially lights up the plurality of light source assemblies based on the operation instruction at the minimum frequency. Then the image collection device collects the first image of the display assembly of the imaging device to be tested, the processor acquires the first image collected by the image collection device, and detects whether the light source assembly is in the lighting state in the first image. If it is detected that the light source assembly is in the lighting state, the frequency is increased by a preset step, an operation instruction is generated based on the increased frequency, and the operation instruction is transmitted to the control module, and the control module sequentially lights up the plurality of light source assemblies based on the operation instruction at the increased frequency. Then the image collection device collects the second image of the display assembly of the imaging device to be tested, and detects whether the light source assembly is in the lighting state in the second image. If it is detected that the light source assembly is in the lighting state, the frequency is continuously increased by the preset step until it is detected that there is no light source assembly in the lighting state in the image collected by the image collection device, and then the frequency of the previous time is taken as the preset frequency. If there is no light source assembly in the lighting state in the display image corresponding to the minimum frequency, it is necessary to confirm whether the state of the imaging device to be tested is abnormal, whether the state of the delay time detection system is abnormal, and if the states of the imaging device to be tested and the delay time detection system are normal, it is still impossible to detect that there is a light source assembly in the lighting state, it is determined that the delay time of the imaging device to be tested exceeds the maximum range of the delay time detection system, and the user is prompted that the detection cannot be completed. The abnormal state of the imaging device to be tested includes: a shutdown state, a fault state, and a function damage state. The abnormal state of the delay time detection system includes: an unstarted state, an abnormal light source device, an abnormal photoelectric detection device, and an abnormal image collection device. In the detection of whether there is a light source assembly in the lighting state in the display image, detection can be performed through a pre-trained deep learning model, or detection can be performed through naked eye observation, and the embodiments of the present application are not limited in this regard.

[0076] For example, the frequency corresponding to the light source device includes three gears 3000 Hz, 1000 Hz and 300 Hz. First, the light source device is controlled to operate at a frequency of 300 Hz, the imaging device to be tested is controlled to operate, and the VST mode is entered. The image acquisition device is controlled to acquire a first image, and it is detected whether the light source component is in the lighting state in the first image. If so, the frequency of the light source device is set to 1000 Hz, the image acquisition device is controlled to acquire a second image, and it is detected whether the light source component is in the lighting state in the second image. If so, the frequency of the light source device is set to 3000 Hz, the image acquisition device is controlled to acquire a display image, and it is detected whether the light source component is in the lighting state in the display image. At this time, if not, the preset frequency of the light source component is determined to be 1000 Hz.

[0077] By determining the preset frequency of the light source device, different preset frequencies are used to detect imaging devices with different delay magnitudes, which further improves the detection accuracy.

[0078] In one embodiment, the processor is further configured to obtain a refresh frequency of a display component of the imaging device to be tested, and set an exposure time of the image acquisition device according to the refresh frequency. Before the image acquisition device acquires the display image, the exposure time of the image acquisition device needs to be set in advance, and the exposure time needs to be less than the refresh frequency of the display component, otherwise the display image acquired may contain two frames of images displayed by the display component itself. The processor can also set the picture storage format, image resolution and rising edge signal trigger image acquisition of the image acquisition device when setting the exposure time of the image acquisition device.

[0079] By setting the exposure time to be less than the refresh frequency of the display component, the display image acquired by the image acquisition device can be more accurate, thereby further improving the detection accuracy.

[0080] In one of the embodiments, the determining of the delay time of the imaging device under test according to the time of the effective signal and the time of the photon capture comprises: determining the delay time of the imaging device under test by subtracting the time of the photon capture T3 from the time of the effective signal T2. The time of the effective signal T2 represents the time of the signal corresponding to the screen lighting of the display component, that is, the time of the display component of the imaging device under test displaying the photons. At this time, the display image captured by the image capture device includes a plurality of light source components in the lighting state. In order to remove the influence of the exposure time of the imaging device under test on the delay time, the photons corresponding to the time of the effective signal T2 are the photons generated by the first light source component in the lighting state in the display image. The time of the photon capture T3 corresponds to the time of the photon capture corresponding to the photons generated by the first light source component in the lighting state in the display image. T2-T3, the delay time of the imaging device under test is obtained, that is, the PTP delay of the imaging device under test is determined.

[0081] In one of the embodiments, the determining of the time of the photon capture of the imaging device under test by image processing of the display image comprises: obtaining a marker light source image; determining first coordinate information of a plurality of marker light source components according to the marker light source image; determining second coordinate information of the first light source component in the lighting state in the display image according to the display image; and determining the time of the photon capture of the imaging device under test according to the first coordinate information, the second coordinate information, and the preset frequency of the light source device.

[0082] Before acquiring the logo light source image, the logo light source image needs to be generated first. First, a plurality of logo light source components are determined at equal intervals in a plurality of light source components of the light source device. For example, the first light source component in the light source device is set as a logo light source component, and then a logo light source component is set every fixed number of intervals. For example, the light source device includes 100 LEDs, the first LED is set as a logo light source component, and every 9 LEDs is set as a logo light source component. For example, the 11th LED is set as a logo light source component, and so on. In this way, the interval between every two logo light source components is 10 LEDs. Control all logo light source components in the light source device to light up, and the remaining light source components to extinguish. The imaging device under test acquires the image of the light source device at this time and displays it on the display component. The image acquisition device acquires the third image of the display component of the imaging device under test at this time. The processor acquires the third image acquired by the image acquisition device. In the third image, the plurality of logo light source components of the light source device are lit up, and the remaining light source components are extinguished. Then control all light source components in the light source device to extinguish. The imaging device under test acquires the image of the light source device at this time and displays it on the display component. The image acquisition device acquires the fourth image of the display component of the imaging device under test at this time. The processor acquires the fourth image acquired by the image acquisition device. In the fourth image, all light source components of the light source device are extinguished. Finally, according to the third image and the fourth image, the logo light source image is determined, as shown in FIG. 10, that is, the third image is subtracted from the fourth image to obtain the logo light source image. Through subtraction, the remaining environmental information in the third image except for the logo light source component is removed, which facilitates subsequent identification of the logo light source image.

[0083] In determining the photon capture time T3 of the imaging device to be tested, first, the marker light source image is acquired; according to the marker light source image, the first coordinate information of the plurality of marker light source components is determined; according to the display image, the second coordinate information of the first light source component in the display image is determined; according to the first coordinate information, the second coordinate information and the preset frequency of the light source device, the photon capture time of the imaging device to be tested is determined. The first coordinate information is the coordinate information of the marker light source component in the marker light source image. Since the structure size of each marker light source component is the same, the coordinate information corresponding to the fixed position of the light source component can be used as the first coordinate information of the corresponding marker light source component. For example, the coordinate information corresponding to the upper left corner pixel point of each marker light source component in the marker light source image can be used as the first coordinate information of the corresponding marker light source component. The second coordinate information is the coordinate information corresponding to the first light source component in the display image. For example, the coordinate information corresponding to the upper left corner pixel point of the first light source component in the display image can be used as the second coordinate information. After determining the plurality of first coordinate information and the second coordinate information, the adjacent first target coordinate information and the second target coordinate information need to be determined in the plurality of first coordinate information according to the plurality of first coordinate information and the second coordinate information. The second coordinate information is between the first target coordinate information and the second target coordinate information. Then, the number of first coordinate information before the first target coordinate information is determined according to the first target coordinate information. Based on the following formula, the photon capture time T3 of the imaging device to be tested is determined.

[0084] Wherein, T is the photon capture time T3; a is the first target coordinate information; b is the second target coordinate information; c is the second coordinate information; f is the frequency of the light source device; k is the coordinate distance between two marker light source components; d is the number of first coordinate information before the first target coordinate information, and each first coordinate information represents a marker light source component.

[0085] In an example, before the photon capture time T3 is calculated, the display image can be processed, i.e. the display image is subtracted from the fourth image to obtain the lighted light source component image. By subtracting, the remaining environmental information in the display image except the lighted light source component is removed, which facilitates subsequent identification of the lighted light source component. As shown in FIG. 11, since all the light source components in the light source device are arranged transversely, the longitudinal coordinate of each light source component is the same, and therefore, the corresponding coordinate information can be expressed by using only the horizontal coordinate. The first coordinate information corresponding to the first marker light source component is 0; the coordinate distance between every two marker light source components is 10; the first coordinate information corresponding to the second marker light source component is 10, and so on; the first coordinate information corresponding to the tenth marker light source component is 90; and the first coordinate information corresponding to the eleventh marker light source component is 100. The second coordinate information is 22. At this time, the first target coordinate information is determined to be 20, and the second target coordinate information is determined to be 30. There are 2 first coordinate information before the first target coordinate information. The frequency of the current light source device is 1000 Hz, i.e. the time interval for lighting between adjacent two light source components is 1 ms. Then the photon capture time T3 is calculated as follows: (22-20) / (30-20) x 1 ms x 10 + 2 x 1 ms x 10 = 22.

[0086] Since the second coordinate information is the coordinate information corresponding to the first light source component in the display image in the lighted state, the photon capture time T3 is the capture time of the photon generated by the first light source component in the display image in the lighted state by the to-be-tested imaging device. Therefore, the photon capture time T3 and the time T2 of the effective signal correspond to the photon generated by the same light source component, and the delay time of the to-be-tested imaging device is determined by subtracting the photon capture time T3 from the time T2 of the effective signal, i.e. the PTP delay of the to-be-tested imaging device.

[0087] The time T2 of the effective signal can be used to accurately determine the photon display time corresponding to the photon generated by the first light source component in the display image in the lighted state. By using the first coordinate information of the plurality of marker light source components in the marker light source image as a time reference, the capture time of the photon generated by the first light source component in the display image in the lighted state by the to-be-tested imaging device can be accurately determined. Finally, the delay time of the to-be-tested imaging device is determined by using the time T2 of the effective signal and the photon capture time T3, which improves the detection accuracy of the delay time.

[0088] In one specific embodiment, as shown in FIG. 12, the three curves in the figure are the total clock source, the event period of the camera of the to-be-tested imaging device, and the refresh period of the display component of the to-be-tested imaging device. When the VST delay, i.e. the PTP delay, of the to-be-tested imaging device is detected.

[0089] First, the delay time detection system is powered on, ensuring that all device components are connected, the processor is connected with all device components, and can communicate normally. The imaging device to be tested is fixed in front of the image acquisition device, and the posture of the imaging device to be tested is adjusted to ensure that the display component of the imaging device to be tested remains centered and clear in the image of the image acquisition device. The light source device is lit at a fixed frequency, and the image acquisition device acquires the image to determine the delay level of the imaging device to be tested, determine the preset time T1, adjust the preset frequency of the light source device to ensure that the preset frequency meets the delay level of the imaging device to be tested. The processor starts the delay detection, and the timer starts timing. When the timer times to T1, the control device acquires the signal of the photoelectric detection device through the signal detection processing module, determines the effective signal, and records the time of the effective signal as T2. At the same time, the control device synchronously triggers the image acquisition device to acquire the image through the imaging trigger module. The image acquisition device transmits the acquired image to the processor. The timer provides time for the processor, and the processor processes the display image to determine the photon capture time T3 of the imaging device to be tested. The delay time of the imaging device to be tested is determined by T2-T3. Specifically as follows:

[0090] Step 1, the time synchronization device controls the light source device, the image acquisition device, the photoelectric detection device and the processor to use a clock source, that is, a total clock source. The processor sets the frequency and brightness of the light source device according to the delay level of the imaging device to be tested. For example, if the VST delay of a known common VR headset is in the millisecond level, the frequency of the light source device can be set to 1000hz@1ms. If the delay level of the imaging device to be tested is unknown, a step-by-step approximation strategy can be used to determine the frequency of the light source device, and the time synchronization device controls the light source device to start working at T0. Specifically as follows:

[0091] First, set the frequency of the light source device to the minimum frequency, and observe the image acquired by the image acquisition device to see if the light source component in the lighting state can be observed. If the light source component in the lighting state can be observed obviously, the next step is performed. If the light source component in the lighting state cannot be observed obviously, the state of the imaging device to be tested and the state of the delay time detection system need to be confirmed to determine whether the delay level of the imaging device to be tested exceeds the maximum range of the delay time detection system. If the light source component in the lighting state can be observed obviously, the frequency of the light source device is increased, and the image acquired by the image acquisition device is observed to see if the light source component in the lighting state can be observed. If it can be observed, the frequency of the light source device is continued to be increased until the light source component in the lighting state cannot be observed, and the last frequency is used as the frequency of the light source device.

[0092] Step 2, the processor transmits a collection instruction to the time synchronization device, and the time synchronization device starts to collect the signal of the photoelectric detection device at a preset time T1 after receiving the collection instruction. T1 needs to be greater than the delay time of the imaging device to be measured. If T1 is less than the delay time of the imaging device to be measured, the display image collected by the image collection device may not be able to observe the light source assembly in the lighting state.

[0093] Step 3, the time synchronization device records the time T2 when the effective signal is collected. The time difference between the preset time T1 and the time T2 when the effective signal is collected is ΔT.

[0094] Step 4, the processor sets the related parameters of the image collection device, such as the exposure time, the picture saving format, the resolution, and the rising edge trigger photographing. The time synchronization device controls the image collection device to collect the current display image of the display assembly at the time T2. The image collection device transmits the collected display image to the processor. As shown in FIG. 6, the black part in the image is the light source assembly in the lighting state, and the continuous multiple light source assemblies in the lighting state are the exposure time of the imaging device to be measured. The processor calculates the display image by an algorithm to determine the photon capture time T3. The specific calculation process is as follows: setting the brightness of the light source device, lighting the marker light source assembly in the light source device, collecting the third image by the image collection device; turning off all the light source assemblies in the light source device, collecting the fourth image by the image collection device. The third image is subtracted from the fourth image to obtain the marker light source image, and the first coordinate information of the multiple marker light source assemblies in the marker light source image is determined; the display image is calculated by using the edge finding and filtering algorithm to determine the second coordinate information of the first light source assembly in the lighting state; according to the first coordinate information, the second coordinate information, and the preset frequency of the light source device, the photon capture time T3 of the imaging device to be measured is determined. The final VST delay, that is, the PTP delay, is T2-T3.

[0095] The embodiment of the present application sets the time measurement target plate with controllable frequency and light intensity, and the time measurement target plate can be connected with the photodetector and the camera of the imaging equipment to be measured, thereby improving the integrity and stability of the delay time detection system. The signal of the photodetector is collected at the preset time T1, and the time when the effective signal is collected is recorded as T2, which excludes the influence of display component refreshing on the delay time, thereby enhancing the accuracy of delay time calculation. The display image is processed to accurately determine the photon capture time T3 of the imaging equipment to be measured, which excludes the influence of the exposure time of the imaging equipment to be measured on the delay time, and indirectly synchronizes the light source device and the camera of the imaging equipment to be measured, thereby improving the detection accuracy of the delay time. The light source device, the image acquisition device, and the photodetector are time-synchronized to avoid the delay time error introduced by the time difference of the delay time detection system itself, thereby improving the detection accuracy of the delay time.

[0096] The delay time detection system provided by the embodiment of the present application can realize the delay time detection of the virtual reality head-mounted display, that is, the delay time detection in the video see-through mode, that is, the delay time detection in the VST mode, and overcomes the influence of the display component frame rate and the exposure time on the delay time in the related art, thereby realizing the objective evaluation of the delay time of different VR headsets in the VST mode. The delay time performance data is provided for the equipment manufacturer, thereby enabling the equipment manufacturer to better optimize the delay time and thereby optimize the VR headset equipment and improve the user experience.

[0097] In the above embodiment, the camera, that is, the image acquisition device, photographs the image presented on the display component of the VR headset, determines the coordinates of the light source component in the image based on the photographed image, and then determines the VST delay based on the coordinates of the light source component. However, the display component of the VR headset has the phenomenon of image jitter and distortion when displaying the image, and the image jitter and distortion will cause inaccurate identification of the coordinates of the light source component, and further cause inaccurate VST delay.

[0098] The VST delay is detected by a delay time detection system, which at least comprises a light source assembly and an image acquisition device configured to capture an image presented on a display assembly of a VR headset, the image comprising an image of the complete light source assembly. The light source assembly comprises a plurality of LED beads arranged in a specific manner (e.g. in a row), with a specific lighting frequency and brightness, so as to achieve a "marquee light" effect, and only one LED bead is lit at the same time. The first LED bead in the light source assembly that is in a lit state is located and identified in the image, and the VST delay is calculated based on the coordinate information of the first LED bead. In the case of multiple rounds of testing of the same VR headset, and locating the first LED bead in the lit state in the image, it is found that the VST delay of the same VR headset should be fixed or fluctuate within a very small range, but the results of the multiple rounds of testing fluctuate within a large range. After in-depth research on the reasons for the large fluctuations, it is found that due to the existence of image jitter and distortion, etc., there is a large difference in the coordinate information of the first LED bead in the lit state in the image based on the coordinate information of the first LED bead in the lit state in the image. The jitter refers to the phenomenon that the display image shakes due to the reasons such as rendering not in time, loss of depth information, etc. when the VR headset processes the image. The distortion refers to the deformation of the image caused by the influence of refraction and reflection of light on the optical design (such as lens, camera sensor), internal imaging system defects or installation errors, etc. in the optical imaging process, such as the image appearing as a barrel or pillow shape.

[0099] As shown in FIG. 13, the ROI black area refers to the area of the LED beads in the lit state in the image captured by the image acquisition device, and since the image acquisition device has an exposure duration, the area generally includes a plurality of LED beads. For example, the exposure duration is 10 ms, and the lighting frequency of the light source is 1000 Hz, i.e. one LED bead is lit every 1 ms, so the number of LED beads in the lit state in the image is 10. The point P is the coordinate of the first LED bead in the lit state in the image, i.e. the position where the left and right pixel values change sharply, and the movement direction of the "marquee light" is from left to right.

[0100] As shown in FIGS. 14a, 14b and 14c, the points P1, P2 and P3 are the positions of the first LED beads in the lit state in the images obtained in different rounds of testing. It can be understood that, according to the calculation principle of the VST delay in the above embodiment, since the positions are different, the VST delays obtained in the different rounds of testing will also be different, resulting in errors in the detected VST delay, and thus the detected VST delay is not accurate enough.

[0101] In one of the embodiments, in order to solve the problem that the detected VST delay is not accurate due to the jitter and distortion of the image, as shown in FIG. 15, a second type of time measurement target plate is provided. Specifically, the time measurement target plate comprises: a light source device; the light source device is provided with a light source area and a mark area; a plurality of light source components are arranged in the light source area according to a preset arrangement rule; a light source mark matching the position of each light source component is arranged in the mark area; when the time measurement target plate is running, the plurality of light source components of the light source device light up at a preset frequency. As an optional solution, the light source components light up in turn at a preset frequency. The light source mark is used to identify the light source components, and through the light source mark, the first LED lamp bead in the lighted state in the light source image can be located and identified, and thus the calculated VST delay avoids the problem that the detected VST delay is not accurate due to the jitter and distortion of the image, thereby improving the accuracy of the detected VST delay.

[0102] Among them, the light source device comprises a plurality of light source components and a light source driving component. The light source component can be an LED lamp bead or any object capable of emitting light.

[0103] The following takes the light source component as an LED lamp bead as an example for description. As shown in FIG. 15, a light source device is provided. The preset arrangement rule can include linear arrangement and array arrangement. The linear arrangement means that all the light source components are arranged in a column. For example, the light source marks can also be arranged in a column, for example, the light source components and the light source marks are arranged alternately to form a column together. The way of alternately arranging can be referred to FIG. 15. The array arrangement can be referred to FIG. 15.

[0104] Among them, the light source mark (Mark) can be a two-dimensional code mark, a bar code mark or any symbol mark capable of recording information, which is used to record the serial number mark and the position mark of each LED lamp bead. It can be understood that the symbol mark is generated based on the serial number mark and the position mark.

[0105] Among them, the serial number mark refers to the ID of each LED lamp bead. Taking 100 LED lamp beads as an example, the serial number mark of each LED lamp bead can be 1-100 in turn.

[0106] Among them, the position mark includes the distance between the light source component and the corresponding light source mark and the corner point information. For example, the Mark is arranged in the shape of a square, and the corner point information is the coordinate information of the four corners of the square. The Mark can also be arranged in other shapes, such as a circle, a rectangle, etc.

[0107] The Mark is not limited in the embodiment, and the information recorded in the Mark can correspond to one LED lamp bead. For example, the light source device 110 includes 100 LED lamp beads, and each LED lamp bead corresponds to one Mark. The Mark can be arranged on the right side of the LED lamp bead as shown in FIG. 3.

[0108] As shown in FIGS. 16 and 17, the Mark can be used to identify the LED lamp bead and frame the area where the corresponding LED lamp bead is located in the image when the Mark is used. The points P1-P4 are points corresponding to the corner point information. The Mark provides the serial number of the LED lamp bead, the corner point information, and the distance of left movement. The corner point information and the distance are used in combination to determine the position of the area where the corresponding LED lamp bead is located, and frame the area where the corresponding LED lamp bead is located.

[0109] The framed area where the corresponding LED lamp bead is located is the ROI area. Then, the pixel value in the area can be obtained according to the ROI detection algorithm. The pixel value is used to determine whether the LED lamp bead in the area is in the lighting state or the extinguishing state.

[0110] The time synchronization device can control the light source device to operate through the light source driving assembly. The light source device 110 can be sequentially lighted from left to right and from top to bottom, or sequentially lighted from right to left and from top to bottom, or sequentially lighted from left to right and from bottom to top, or sequentially lighted from right to left and from bottom to top. The time synchronization device 120 can also control the lighting frequency and brightness of the light source device 110 through the light source driving assembly, so as to achieve the effect of a running marquee.

[0111] Based on the same inventive concept, the embodiment of the present application also provides a delay time detection method applied to the delay time detection system. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme described in the system, and therefore the specific limitations in one or more delay time detection method embodiments provided below can refer to the limitations of the delay time detection system described above, and will not be repeated here.

[0112] In one embodiment, as shown in FIG. 18, a delay time detection method is provided, which is applied to the delay time detection system in FIG. 4 and includes the following steps:

[0113] In step 1801, the light source device is controlled to operate at a preset frequency, so that the imaging device to be tested collects the image of the light source device and displays the image on the display assembly of the imaging device to be tested.

[0114] Step 1802, start collecting the signal of the photoelectric detection device at a preset time, record the effective signal time, and trigger the image acquisition device to collect the display image of the imaging equipment to be measured at the effective signal time.

[0115] Step 1803, receive the display image collected by the image acquisition device, and determine the photon capture time of the imaging equipment to be measured based on the display image.

[0116] Step 1804, determine the delay time of the imaging equipment to be measured according to the effective signal time and the photon capture time.

[0117] When setting the preset frequency of the light source device, the processor obtains the delay magnitude of the imaging equipment to be measured; according to the delay magnitude, the preset frequency of the light source device is determined; and the light source device is controlled to operate at the preset frequency.

[0118] When setting the preset frequency of the light source device, the processor controls the light source device to operate at the minimum frequency; obtains the first image collected by the image acquisition device, and if it is detected that the light source component is in the lighting state in the first image, the frequency is increased by a preset step, and the light source device is controlled to operate at the increased frequency; obtains the second image collected by the image acquisition device, and if it is detected that the light source component is in the lighting state in the second image, the frequency is continued to be increased by a preset step until it is detected that there is no light source component in the lighting state in the image collected by the image acquisition device, then the frequency of the last time is taken as the preset frequency; and the light source device is controlled to operate at the preset frequency.

[0119] For the first type of time measurement calibration plate, the specific limitation can be referred to the limitation of the delay time detection system in the foregoing. The delay time of the imaging equipment to be measured is determined as follows:

[0120] The light source device includes a plurality of light source components arranged in sequence and a light source driving component; the light source driving component is connected with the plurality of light source components and the time synchronization device respectively. The time synchronization device receives the operation instruction of the processor, controls the light source driving component to light up the plurality of light source components at a preset frequency. That is, the time synchronization device controls the light source driving component to light up the plurality of light source components at a preset frequency. The time synchronization device is also used to control the clock of the image acquisition device, the photoelectric detection device and the light source device to be synchronized.

[0121] The processor controls the light source device to operate at a preset frequency, so that the imaging device under test acquires an image of the light source device and displays the image on a display component of the imaging device under test. The time synchronization device receives an acquisition instruction of the processor, starts to acquire a signal of the photoelectric detection device at a preset time, records a valid signal time, and synchronously triggers the image acquisition device to acquire a display image of the imaging device under test at the valid signal time. The processor receives the display image acquired by the image acquisition device, and determines a photon capture time of the imaging device under test based on the display image. According to the valid signal time and the photon capture time, a delay time of the imaging device under test is determined. The preset time T1 is greater than a nominal delay time of the imaging device under test, and is less than or equal to a maximum delay time measurement range of the light source device at the preset frequency. When the photon capture time of the imaging device under test is determined, the processor acquires a marker light source image; according to the marker light source image, first coordinate information of a plurality of marker light source components is determined; according to the display image, second coordinate information of a first lighted light source component in the display image is determined; and according to the first coordinate information, the second coordinate information, and the preset frequency of the light source device, the photon capture time T3 of the imaging device under test is determined. Before the marker light source image is acquired, the processor acquires a third image acquired by the image acquisition device; a plurality of marker light source components of the light source device are lighted in the third image; a fourth image acquired by the image acquisition device is acquired; all light source components of the light source device are extinguished in the fourth image; and according to the third image and the fourth image, the marker light source image is determined. The processor determines the delay time of the imaging device under test by subtracting the photon capture time T3 from the time T2 at which the valid signal is acquired.

[0122] For the second type of time measurement target plate, specific limitations can be referred to the limitations of the delay time detection system in the foregoing. The delay time of the imaging device under test is specifically determined as follows:

[0123] Step 1801, the light source device is controlled to operate at a preset frequency, so that the imaging device under test acquires an image of the light source device and displays the image on a display component of the imaging device under test.

[0124] The processor generates an operation instruction, controls the light source device to operate at a preset frequency through the operation instruction, and controls the imaging device under test to operate. After the imaging device under test operates, the imaging device under test acquires an image of the light source device and displays the image on a display component of the imaging device under test.

[0125] Step 1802, a signal of the photoelectric detection device is acquired at a preset time, a valid signal time is recorded, and an image acquisition device is synchronously triggered to acquire a display image of the imaging device under test at the valid signal time.

[0126] The time synchronization device receives a collection instruction of the receiving processor, and starts to collect a signal of the photoelectric detection device at a preset time.

[0127] In step 1803, the display image collected by the image collection device is received, and a photon capture time of the imaging equipment under test is determined based on the display image.

[0128] The processor receives the display image collected by the image collection device, and determines the photon capture time of the imaging equipment under test based on the display image.

[0129] It can be understood that the display image has image information of the Mark in the identification area, and the first light source component in a lighting state in the image can be located according to the image information, so that the photon capture time can be calculated according to the serial number identification of the light source component.

[0130] The photon capture time of the imaging equipment under test is determined based on the display image, and the Mark detection algorithm is used to achieve this. Specifically, all light source identifications in the display image are identified according to the display image. The program corresponding to the Mark detection algorithm can identify a specific type of Mark from the display image, and then parse the Mark to obtain the coding information therein, i.e., the serial number identification and the position identification. The specific type refers to the type of Mark encoded by the serial number identification and the position identification in the embodiment of the application. It can be understood that there is other information in the display image, such as the light source component area. In order to avoid misidentification of other information by the Mark detection algorithm, the Mark detection algorithm in the embodiment of the application can identify and process the specific type of Mark, and if the specific type of Mark is not detected, the execution process of the Mark detection algorithm is exited.

[0131] After all the light source identifications (i.e., Marks) that can be identified are identified from the display image by the Mark detection algorithm, all light source component areas in the display image are determined according to all the light source identifications; the first serial number identification of the first target light source component is determined according to all the light source component areas; and the photon capture time of the imaging equipment under test is determined according to the first serial number identification and the preset frequency of the light source device.

[0132] The first target light source component refers to the first light source component in the image in a lighting state. Whether the light source component is in the lighting state or not can be determined by the average pixel value of the light source component region. Specifically, the average pixel value can be compared with a preset pixel value threshold. If the average pixel value is greater than the preset pixel value threshold, it is determined that the corresponding light source component is in the lighting state. If the average pixel value is less than or equal to the preset pixel value threshold, it is determined that the corresponding light source component is in the extinguishing state. The preset pixel value threshold can distinguish whether the light source component is in the lighting state or the extinguishing state. For example, the preset pixel value threshold can be 100, 150, etc.

[0133] The light source identifier is a symbol identifier obtained after coding. Therefore, the information carried by the light source identifier, i.e., the position identifier and the serial number identifier, needs to be decoded. That is, according to all the light source identifiers, the position identifier and the serial number identifier corresponding to all the light source identifiers can be determined. Then, according to all the position identifiers and the serial number identifiers, all the light source component regions in the display image and the serial number identifier corresponding to each light source component region can be determined.

[0134] Each light source component region can be obtained by moving the corresponding identifier region. How to move can be determined by the position identifier. For example, the identifier region is a square, and the position identifier includes corner point information and a distance of movement, as shown in FIG. 16. The coordinates of the corner point information, i.e., points P1-P4, are moved to the left by the distance. In addition, the light source component region can also be constructed by the position identifier, i.e., the coordinate information obtained by moving the coordinate information in the position identifier. In summary, each light source component region can be obtained. For example, if there are 100 light source components, 100 light source component regions corresponding to the light source components can be obtained.

[0135] For how to determine the first serial number identifier of the first target light source component according to all the light source component regions, one can refer to an example in FIG. 19 for understanding. The present application provides three determination methods, which are: traversal method, fast grouping method, and multi-thread method.

[0136] For the traversal method, all the light source component regions are traversed to detect the lighting component region, to determine a plurality of lighting component regions and the serial number identifier corresponding to each lighting component region. The serial number identifier corresponding to the minimum in the plurality of lighting component regions is taken as the first serial number identifier of the first target light source component. That is, the lighting component region detection is started with any light source component region, and the lighting component region detection of other light source component regions is sequentially completed to obtain a plurality of lighting component regions and the serial number identifier corresponding to each lighting component region. The serial number identifier corresponding to the minimum in the plurality of lighting component regions is found and taken as the first serial number identifier of the first target light source component.

[0137] For the fast grouping method, first, all the light source assembly regions are divided into a plurality of light source groups in a preset number, then the first light source assembly region in each of the light source groups is subjected to the light-on assembly region detection to determine a first target light-on assembly region; the light-on assembly region detection is performed in a direction in which the serial number identifier decreases from the first target light-on assembly region as a starting position; the serial number identifier corresponding to the last detected light-on assembly region is taken as the first serial number identifier of the first target light source assembly. The preset number can be set as needed, and the embodiment is not limited.

[0138] Exemplarily, the light-on assembly region detection is performed on the first light source assembly region in each of the light source groups, one, two or more than two first target light-on assembly regions can be obtained. For example, the number of light source assembly regions is 100, the serial number identifiers of the corresponding light source assemblies can be 1-100 in turn, the preset number is 10, then 10 light source groups can be obtained, the serial number identifiers of the first light source assembly regions of the light source groups are 1, 11, 21, and so on. Correspondingly, the first target light-on assembly region can be one, two or more than two, for example, the first target light-on assembly region is one, and the corresponding serial number identifier is 21.

[0139] Correspondingly, if the first target light-on assembly region is one, the light-on assembly region detection is performed in a direction in which the serial number identifier decreases from the first target light-on assembly region as a starting position; if no light-on assembly region is detected, the serial number identifier corresponding to the first target light-on assembly region is taken as the first serial number identifier of the first target light source assembly; if a light-on assembly region is detected, the serial number identifier corresponding to the last detected light-on assembly region is taken as the first serial number identifier of the first target light source assembly.

[0140] If the first target light-on assembly region is two or more than two, first, the first target light-on assembly region corresponding to the minimum serial number identifier is determined from the first target light-on assembly regions, then the light-on assembly region detection is performed in a direction in which the serial number identifier decreases from the first target light-on assembly region corresponding to the minimum serial number identifier as a starting position; if no light-on assembly region is detected, the serial number identifier corresponding to the first target light-on assembly region corresponding to the minimum serial number identifier is taken as the first serial number identifier of the first target light source assembly; if a light-on assembly region is detected, the serial number identifier corresponding to the last detected light-on assembly region is taken as the first serial number identifier of the first target light source assembly.

[0141] For the multi-thread method, according to the serial number identifier corresponding to each light source component area, the first light source component area is taken as the starting position to detect the light-on component area in the direction of increasing serial number identifier; the serial number identifier corresponding to the first detected light-on component area is taken as the first serial number identifier of the first target light source component. While detecting the light-on component area in the direction of increasing serial number identifier from the first light source component area as the starting position, the light-on component area can also be detected in the direction of decreasing serial number identifier from the last light source component area as the starting position.

[0142] For the two detection directions described above, when the first target light source component is detected in either detection direction, the detection in both directions stops. If the light-on component area is detected first in the detection direction of detecting the light-on component area in the direction of increasing serial number identifier from the first light source component area as the starting position, the serial number identifier corresponding to the first light-on component area is taken as the first serial number identifier of the first target light source component; if the light-on component area is detected in the detection direction of detecting the light-on component area in the direction of decreasing serial number identifier from the last light source component area as the starting position, the detection continues until the light-off component area is detected first. If the light-off component area is detected, the serial number identifier corresponding to the last light-on component area detected during the detection is taken as the first serial number identifier of the first target light source component.

[0143] After determining the first serial number identifier based on the three determination methods described above, the photon capture time T3 of the imaging device to be tested can be determined based on the first serial number identifier by the following specific formula: T3 = Ts x v

[0144] Wherein, Ts is the first serial number identifier; v is the speed of the light source component when the "marquee" effect is generated, which can be calculated by the preset frequency of the light source device, that is, the inverse of the preset frequency.

[0145] Step 1004, determining the delay time of the imaging device to be tested according to the valid signal time and the photon capture time.

[0146] The VST delay time can include or not include the exposure time of the camera of the VR head-mounted display.

[0147] For the VST delay time including the exposure time of the camera of the VR head-mounted display, the VST delay time can be directly determined according to the valid signal time and the photon capture time, and the formula for calculating the delay time T is as follows: T = T1 + ΔT - T3

[0148] Wherein, T1 is the preset time described above, ΔT is the time difference between the preset time T1 and the valid signal time T2, that is, T1 + ΔT = T2; T3 is the photon capture time.

[0149] For the VST delay, the exposure time of the camera not including the VR head-mounted display can be determined according to the effective signal moment, the photon capture moment and the exposure duration, and the formula for calculating the delay time T is as follows: T=T1+ΔT-T3-Texp

[0150] Wherein, T1 is the preset moment, ΔT is the time difference between the preset moment T1 and the effective signal moment T2, i.e. T1+ΔT=T2; T3 is the photon capture moment; Texp is the exposure time.

[0151] The following describes how to determine the exposure time Texp:

[0152] The exposure time Texp can be determined after determining all light source component regions in the display image, according to the second serial number identifier of the second target light source component, and according to the first serial number identifier, the second serial number identifier and the preset frequency of the light source device, the exposure duration of the imaging device under test is determined.

[0153] Wherein, the second target light source component refers to the light source component with the largest serial number identifier in the lighting state.

[0154] Wherein, the exposure duration Texp can be determined by the following formula: Texp=(Te-Ts)×v

[0155] Wherein, Te refers to the second serial number identifier, Ts refers to the first serial number identifier, and v is the speed of the light source component when it produces a "marquee" effect, which can be calculated by the preset frequency of the light source device, i.e. the inverse of the preset frequency.

[0156] For example, for how to determine the second serial number identifier, similar to the determination of the first serial number identifier, it can also be understood by referring to one of the examples in FIG. 19, and three determination methods are provided in the embodiments of the application, which are: traversal method, fast grouping method and multi-threading method.

[0157] For the traversal method, all the light source component regions are traversed to detect the lighting component regions, determine a plurality of lighting component regions and the serial number identifier corresponding to each lighting component region; the largest serial number identifier corresponding to the plurality of lighting component regions is taken as the second serial number identifier of the second target light source component. That is, any light source component region starts to perform lighting component region detection, and the lighting component region detection of other light source component regions is sequentially completed to obtain a plurality of lighting component regions and the serial number identifier corresponding to each lighting component region. The largest serial number identifier corresponding to the plurality of lighting component regions is found and taken as the second serial number identifier of the second target light source component.

[0158] For the fast grouping method, first, all the light source assembly regions are divided into a plurality of light source groups in a preset number, then the first light source assembly region in each light source group is detected to determine a second target light-on assembly region, then the second target light-on assembly region is taken as a starting position to perform light-on assembly region detection in the direction of increasing serial number identification, and the serial number identification of the last detected light-on assembly region is taken as a second serial number identification of a second target light source assembly. The preset number can be set as needed, and the embodiment is not limited.

[0159] Exemplarily, the first light source assembly region in each light source group is detected to obtain one, two or more than two second target light-on assembly regions. For example, if the number of light source assembly regions is 100, the serial number identification of the corresponding light source assembly can be 1-100 in turn, the preset number is 10, then 10 light source groups can be divided, and the serial number identification of the first light source assembly region of each light source group is 1, 11, 21, and so on. Correspondingly, the second target light-on assembly region can be one, two or more than two, for example, the second target light-on assembly region is one, and the corresponding serial number identification is 21.

[0160] Correspondingly, if the second target light-on assembly region is one, the second target light-on assembly region is taken as a starting position to perform light-on assembly region detection in the direction of increasing serial number identification, if no light-on assembly region is detected, the serial number identification corresponding to the second target light-on assembly region is taken as a second serial number identification of a second target light source assembly, if a light-on assembly region is detected, the serial number identification corresponding to the last detected light-on assembly region is taken as a second serial number identification of a second target light source assembly.

[0161] If the second target light-on assembly region is two or more than two, first, the second target light-on assembly region corresponding to the maximum serial number identification is determined from the second target light-on assembly regions, then the second target light-on assembly region corresponding to the maximum serial number identification is taken as a starting position to perform light-on assembly region detection in the direction of increasing serial number identification, if no light-on assembly region is detected, the serial number identification corresponding to the second target light-on assembly region corresponding to the maximum serial number identification is taken as a second serial number identification of a second target light source assembly, if a light-on assembly region is detected, the serial number identification corresponding to the last detected light-on assembly region is taken as a second serial number identification of a second target light source assembly.

[0162] For the multi-thread method, according to the serial number identifier corresponding to each light source component area, the last light source component area is taken as the starting position to detect the light-on component area in the direction of decreasing serial number identifier; the serial number identifier corresponding to the first detected light-on component area is taken as the second serial number identifier of the second target light source component. While detecting the light-on component area in the direction of decreasing serial number identifier from the last light source component area as the starting position, the first light source component area can be taken as the starting position to detect the light-on component area in the direction of increasing serial number identifier.

[0163] In addition, the second serial number identifier can also be determined through the above-mentioned embodiments corresponding to the two detection directions. The difference between the embodiments is that the second serial number identifier is determined in the embodiment, rather than the first serial number identifier. The specific determination process is not repeated here.

[0164] An optional embodiment of the detection process of the system is described below in combination with FIG. 20, which includes steps 1 to 5, wherein:

[0165] Step 1: Set the light source flicker frequency and brightness, that is, set the light-on frequency and brightness of the light source components in the light source device.

[0166] Step 2: Set the relative light source starting time T1 of the PD operation, that is, set the preset time of the photodiode. When the time synchronization device timing reaches the preset time, the signal of the photodiode is collected.

[0167] Step 3: Record the time difference ΔT of the generation time of the PD response pulse signal (that is, the effective signal time T2) relative to the preset time T1 when the screen is refreshed.

[0168] Step 4: Use the PD response pulse signal to trigger the detection camera to capture the image under the VR headset perspective picture, and call the program corresponding to the delay time detection method to calculate the photon capture time T3 through the image.

[0169] Step 5: Based on the above-mentioned acquired time, the final delay value (VST delay) T = T1 + ΔT - T3 is calculated.

[0170] It should be understood that although the steps in the flowcharts related to the embodiments described above are shown in a sequence as indicated by arrows, the steps are not necessarily executed in the order as indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not necessarily limited in sequence, and the steps can be executed in other sequences. Moreover, at least some of the steps in the flowcharts related to the embodiments described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution of the steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least some of the other steps or the steps or stages in the other steps.

[0171] It can be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiments. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0172] Any combination of the technical features in the above embodiments can be made. For the sake of brevity, the foregoing description has not described all possible combinations of the technical features in the above embodiments, however, as long as the combination of the technical features does not contradict, it should be considered within the scope of the present disclosure.

[0173] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A delay time detection system characterized by, The application discloses a time delay detection system for an imaging device to be tested, which comprises a time measurement target plate, an image acquisition device, a photoelectric detection device and a processor. The time measurement target plate comprises a light source device and a time synchronization device. The imaging device to be tested is arranged between the time measurement target plate and the image acquisition device, and is used for acquiring an image of the light source device and displaying the image on a display component of the imaging device to be tested. The image acquisition device is used for acquiring a display image of the display component of the imaging device to be tested and transmitting the display image to the processor. The photoelectric detection device is arranged in front of the display component of the imaging device to be tested, and is used for detecting refreshing of the display component. The processor is used for controlling the light source device to operate at a preset frequency. The time synchronization device is used for receiving an acquisition instruction of the processor, starting to acquire an effective signal of the photoelectric detection device at a preset time, and synchronously triggering the image acquisition device to acquire an image at a time when the effective signal is acquired. The processor is further used for receiving the display image acquired by the image acquisition device, performing image processing on the display image to determine a photon capture time of the imaging device to be tested, and determining a time delay of the imaging device to be tested according to the time when the effective signal is acquired and the photon capture time.

2. The system of claim 1, wherein, The time synchronization device comprises a control module, a time synchronization module, an imaging triggering module and a signal detection processing module. The time synchronization module is connected with the image acquisition device, the photoelectric detection device and the light source device, and is used for controlling clock synchronization of the image acquisition device, the photoelectric detection device and the light source device. The control module is connected with the processor, is used for receiving an acquisition instruction of the processor, and starts to acquire a signal of the photoelectric detection device through the signal detection processing module at a preset time. The signal detection processing module is connected with the photoelectric detection device, is used for acquiring a signal of the photoelectric detection device, determining an effective signal, and transmitting the effective signal to the control module. The control module is further used for recording a time when the effective signal is acquired, synchronously triggering the image acquisition device to acquire an image through the imaging triggering module at the time when the effective signal is acquired, and transmitting the time when the effective signal is acquired to the processor. The imaging triggering module is connected with the image acquisition device, and is used for triggering the image acquisition device to acquire an image based on an instruction of the control module.

3. The system of claim 2, wherein, The time synchronization device further comprises a timer. The control module is further used for receiving an operation instruction of the processor, and transmitting the operation instruction to the timer. The timer is used for starting timing based on the operation instruction, and transmitting timing information to the control module. The control module is further configured to start, based on the timing information, the signal detection processing module to collect signals of the photoelectric detection device at a preset time; and record, based on the timing information, a time when valid signals are collected.

4. The system of claim 1, wherein, The light source device comprises a plurality of light source assemblies arranged in sequence and a light source driving assembly; The light source driving assembly is connected with the plurality of light source assemblies and the time synchronization device.

5. The system of claim 4, wherein, The time synchronization device is further configured to receive a running instruction of the processor, and control the light source driving assembly to light up the plurality of light source assemblies at a preset frequency.

6. The system of claim 5, wherein, The time synchronization device is further configured to control the light source driving assembly to light up the plurality of light source assemblies in sequence at a preset frequency.

7. The system of any one of claims 4 to 6, wherein, The plurality of light source assemblies are independently driven.

8. The system of claim 1, wherein, The light source device is provided with a light source area and an identification area; The plurality of light source assemblies are arranged in the light source area according to a preset arrangement rule; and the identification area is provided with a light source identification matching a position of each light source assembly; When the time measurement target plate is running, the plurality of light source assemblies of the light source device are lighted up at a preset frequency.

9. The system of claim 8, wherein, The plurality of light source assemblies are arranged in a linear arrangement manner or an array arrangement manner.

10. The system of claim 8, wherein, The light source identification is generated based on position identification and serial number identification of the light source assembly at a corresponding position.

11. The system of claim 10, wherein, The light source identification comprises a two-dimensional code identification.

12. The system of claim 1, wherein, The photoelectric detection device comprises a photoelectric detection assembly and a post-processing circuit; The photoelectric detection assembly is connected with the post-processing circuit, configured to detect refreshing of the display assembly, generate a photoelectric current signal, and transmit the photoelectric current signal to the post-processing circuit; The post-processing circuit is connected with the time synchronization device, configured to convert the photoelectric current signal into a voltage signal, and transmit the voltage signal to the time synchronization device.

13. The system of claim 12, wherein, The post-processing circuit comprises a gain adaptive circuit; The gain adaptive circuit is connected with the photoelectric detection assembly and the time synchronization device, configured to convert the photoelectric current signal into a voltage signal based on a preset gain, and transmit the voltage signal to the time synchronization device.

14. The system of claim 13, wherein, The post-processing circuit further comprises a false trigger circuit; The false trigger circuit is connected between the gain adaptive circuit and the time synchronization device, configured to filter the voltage signal based on a preset voltage threshold, and transmit the filtered voltage signal to the time synchronization device.

15. The system of claim 13 or claim 14, wherein, The time synchronization device is connected with the gain adaptive circuit, and is further configured to collect a voltage signal of the gain adaptive circuit before a preset time, determine a frequency parameter and a voltage parameter of the voltage signal, and generate a gain adjustment signal based on the frequency parameter or the voltage parameter; and transmit the gain adjustment signal to the gain adaptive circuit. The gain adaptive circuit is further configured to adjust the preset gain according to the gain adjustment signal.

16. The system of claim 12, wherein, The photoelectric detection assembly is integrated in the image acquisition device.

17. The system of claim 12, wherein, The photoelectric detection device is fixedly arranged between the image acquisition device and the imaging equipment to be tested.

18. The system of claim 16 or claim 17, wherein, The photoelectric detection assembly is arranged in the middle of the lower end of the image acquisition device.

19. The system of claim 16, wherein, The photoelectric detection assembly is arranged separately from the post-processing circuit.

20. The system of claim 1, wherein, The processor is connected with the imaging equipment to be tested, and controls the operation of the imaging equipment to be tested.

21. The system of claim 1, wherein, The control of the light source device to operate at the preset frequency comprises: acquiring a time delay magnitude of the imaging equipment to be tested; determining the preset frequency of the light source device according to the time delay magnitude; controlling the light source device to operate at the preset frequency.

22. The system of claim 1, wherein, The control of the light source device to operate at the preset frequency comprises: controlling the light source device to operate at a minimum frequency; acquiring a first image collected by the image acquisition device, and if it is detected that there is a light source assembly in a lighted state in the first image, increasing the frequency by a preset step, and controlling the light source device to operate at the increased frequency; acquiring a second image collected by the image acquisition device, and if it is detected that there is a light source assembly in a lighted state in the second image, continuing to increase the frequency by the preset step, until it is detected that there is no light source assembly in a lighted state in the image collected by the image acquisition device, and then taking the frequency of the previous time as the preset frequency; controlling the light source device to operate at the preset frequency.

23. The system of claim 1, wherein, The preset time is greater than a nominal time delay of the imaging equipment to be tested, and is less than or equal to a maximum time delay measurement range of the light source device at the preset frequency.

24. The system of claim 1, wherein, The image processing of the display image to determine the photon capture time of the imaging equipment to be tested comprises: acquiring a marker light source image; determining first coordinate information of a plurality of marker light source assemblies according to the marker light source image; determining second coordinate information of a first lighted light source assembly in the display image according to the display image; determining the photon capture time of the imaging equipment to be tested according to the first coordinate information, the second coordinate information, and the preset frequency of the light source device.

25. The system of claim 24, wherein, Before the acquisition of the marker light source image, the following steps are further included: acquiring a third image collected by the image acquisition device; a plurality of marker light source assemblies of the light source device are lighted in the third image; acquiring a fourth image collected by the image acquisition device; all light source assemblies of the light source device are extinguished in the fourth image; Determine a marker light source image according to the third image and the fourth image.

26. The system of claim 1, wherein, The determining of the delay time of the imaging device under test according to the time when the valid signal is collected and the photon capture time comprises: The delay time of the imaging device under test is determined by subtracting the photon capture time from the time when the valid signal is collected.

27. A delay time detection method characterized by, The method comprises: Controlling the light source device to operate at a preset frequency, so that the imaging device under test collects an image of the light source device and displays the image on a display component of the imaging device under test; Starting to collect a signal of the photoelectric detection device at a preset time, recording a valid signal time, and synchronously triggering the image collection device to collect a display image of the imaging device under test at the valid signal time; Receiving the display image collected by the image collection device, and determining a photon capture time of the imaging device under test based on the display image; Determine the delay time of the imaging device under test according to the valid signal time and the photon capture time.

28. The method of claim 27, wherein, The determining of the photon capture time of the imaging device under test based on the display image comprises: Obtain a marker light source image; Determine first coordinate information of a plurality of marker light source components according to the marker light source image; Determine second coordinate information of a first light source component that is lit in the display image according to the display image; Determine the photon capture time of the imaging device under test according to the first coordinate information, the second coordinate information, and a preset frequency of the light source device.

29. The method of claim 28, wherein, The method further comprises: Obtain a third image collected by the image collection device; a plurality of marker light source components of the light source device are lit in the third image; Obtain a fourth image collected by the image collection device; all light source components of the light source device are extinguished in the fourth image; Determine a marker light source image according to the third image and the fourth image.

30. The method of claim 27, wherein, The determining of the photon capture time of the imaging device under test based on the display image comprises: Identify all light source markers in the display image according to the display image; Determine all light source component regions in the display image according to all the light source markers; Determine a first serial number identifier of a first target light source component according to all the light source component regions; Determine the photon capture time of the imaging device under test according to the first serial number identifier and a preset frequency of the light source device.

31. The method of claim 30, wherein, The determining of all light source component regions in the display image according to all the light source markers comprises: Determine position identifiers and serial number identifiers corresponding to all the light source markers according to all the light source markers; Determine all light source component regions in the display image and serial number identifiers corresponding to each light source component region according to all the position identifiers and serial number identifiers.

32. The method of claim 30, wherein, The determining of a first serial number identifier of a first target light source component according to all the light source component regions comprises: Iterate all the light source component regions to detect lit component regions, determine a plurality of lit component regions and serial number identifiers corresponding to each lit component region; Take a serial number identifier corresponding to a smallest lit component region as the first serial number identifier of the first target light source component.

33. The method of claim 30, wherein, The first serial number of the first target light source component is determined according to all the light source component regions. A first lighted component region is detected from a first light source component region in a direction of increasing serial number, according to the serial number of each light source component region. The serial number of the detected first lighted component region is taken as the first serial number of the first target light source component.

34. The method of claim 30, wherein, The first serial number of the first target light source component is determined according to all the light source component regions. All the light source component regions are divided into a plurality of light source groups in a preset number. A first lighted component region in each light source group is detected to determine a first target lighted component region. A lighted component region is detected from the first target lighted component region in a direction of decreasing serial number. The serial number of the detected last lighted component region is taken as the first serial number of the first target light source component.

35. The method of claim 30, wherein, After determining all the light source component regions in the display image according to all the light source identifiers, the method further comprises: A second serial number of a second target light source component is determined according to all the light source component regions. An exposure time of the imaging device under test is determined according to the first serial number, the second serial number, and a preset frequency of the light source device.

36. The method of claim 35, wherein, The second serial number of the second target light source component is determined according to all the light source component regions. A plurality of lighted component regions and a serial number corresponding to each lighted component region are determined by detecting a lighted component region from all the light source component regions. The serial number corresponding to the largest of the plurality of lighted component regions is taken as the second serial number of the second target light source component.

37. The method of claim 35, wherein, The second serial number of the second target light source component is determined according to all the light source component regions. A lighted component region is detected from a last light source component region in a direction of decreasing serial number, according to the serial number of each light source component region. The serial number of the detected first lighted component region is taken as the second serial number of the second target light source component.

38. The method of claim 35, wherein, The second serial number of the second target light source component is determined according to all the light source component regions. All the light source component regions are divided into a plurality of light source groups in a preset number. A first lighted component region in each light source group is detected to determine a second target lighted component region. A lighted component region is detected from the second target lighted component region in a direction of increasing serial number. The serial number of the detected last lighted component region is taken as the second serial number of the second target light source component.

39. The method of claim 35, wherein, The delay time of the imaging device under test is determined according to the effective signal time and the photon capture time. The delay time of the imaging device under test is determined according to the effective signal time, the photon capture time, and the exposure time.

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