A method for testing MTP of VR

Abstract

The application discloses a kind of MTP test methods of VR, test method includes the following steps: A, high-speed camera starts shooting;B, three-axis high-precision rotary table simulates human rotation;C, VR equipment judges whether rotation is greater than angle a (a is less than or equal to 0.1 °);D, no, three-axis high-precision rotary table continues to simulate human rotation, yes, VR glasses start rendering;E, asynchronous time warp.The whole process can be recovered by the method, accurate to 0.1 ms, the test environment is stable, ensures that IMU (Inertial measurement unit) is not affected by the environment, reduces system error, by adjusting three-axis rotary table, real simulation head wearing condition, high-precision rotary table and HMD (Head Mounted Display) synchronous motion, high-precision rotary table and HMD and computer system form human head motion simulation system, computer system is connected with HMD high-precision rotary table by USB (Universal Serial BUS) and obtains the motion data of HMD and rotary table in real time, high-precision rotary table is composed of base outer frame, middle frame and corresponding motor, three-frame position accuracy ≤±5", repeat position accuracy ≤±5", angular velocity accuracy 0.001 ° / s.

Description

Technical Field

[0001] This invention relates to the field of VR technology, specifically to an MTP testing method for VR. Background Technology

[0002] Virtual reality (VR) technology is a brand-new practical technology that emerged in the 20th century. It encompasses computer, electronic information, and simulation technology. Its basic implementation method is to simulate a virtual environment by computer, thereby giving people a sense of immersion. With the continuous development of social productivity and science and technology, the demand for VR technology in various industries is growing stronger. VR technology has also made great progress and is gradually becoming a new scientific and technological field. However, the MTP (Mean Transmission Test) method in VR is not comprehensive, cannot observe the entire process, and has an unstable test environment with large errors. In addition, it differs from actual application scenarios. Therefore, we propose a VR MTP test method. Summary of the Invention

[0003] The purpose of this invention is to provide an MTP testing method for VR to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an MTP testing method for VR, the testing method comprising the following steps:

[0005] A. The high-speed camera starts shooting;

[0006] B. A three-axis high-precision turntable simulates human body rotation;

[0007] C. The VR device determines whether the rotation is greater than angle a (a is less than or equal to 0.1°);

[0008] D. If no, the three-axis high-precision turntable continues to simulate human body rotation; if yes, the VR glasses begin rendering.

[0009] E. Asynchronous time warp;

[0010] F. The screen displays white;

[0011] G. The high-speed camera stops shooting;

[0012] H. Analyze and calculate the captured images.

[0013] Preferably, the high-speed camera is bidirectionally connected to a PC via a 10 Gigabit Ethernet card, and the PC includes control and shooting software and analysis and calculation software. The output end of the control and shooting software is connected to the input end of the analysis and calculation software. Another input end of the high-speed camera is connected to the output end of a high-precision three-axis turntable. The high-precision three-axis turntable includes an HMD, an HMD fixture, and a three-axis IMU+GYRO sensor. The HMD includes a Display, a GPU, a CPU, and an IMU. At the same time, the high-precision three-axis turntable is also bidirectionally connected to another PC, and the other PC includes turntable control software.

[0014] Preferably, the test needs to be conducted under natural light (constant light) or flicker-free ambient lighting (to reduce algorithm calculation errors), and the specific test method is as follows: ① Configure the high-speed camera frame rate and start shooting; ② Initialize the high-precision turntable and simulate the rotation of a human head; ③ The HMD determines whether the threshold has been reached; ④ When the threshold is exceeded, the HMD starts rendering; ⑤ After rendering, asynchronous time warping is performed, and after the warping is completed, the data is transmitted to the screen via MIPI to complete the on-screen display; ⑥ After capturing the image, the analysis software reads and analyzes the MTP time.

[0015] Preferably, the high-speed camera has a resolution greater than 800 (width) * 600 (height) pixels, a frame rate greater than 1000fps, an exposure time in the microsecond range, a zoomable lens, and a field of view greater than 60°. Since the speed at which a computer's hard drive stores images cannot keep up with the frame rate of the high-speed camera, the images need to be saved to the computer's cache first, and then read from the cache and saved to the hard drive. Therefore, the computer's memory needs to be greater than 32GB. When shooting, the camera's exposure time, frame rate, and pixels are configured through the computer, and then the lens is aligned with the HMD lens, and the distance and lens focal length are adjusted to make the image on the computer clear.

[0016] Preferably, the image catalog acquired by the high-speed camera is input to the image processing module. The image processing module extracts the first image in the catalog as the reference image, traverses all images in the catalog, calculates the difference between each image and the reference image, and obtains the difference image. Since the HMD lens area will also flicker when the turntable is not rotating, in order to eliminate interference, the lens area is removed when calculating the turntable rotation state. Therefore, the lens area of ​​the difference image is set to 0.

[0017] Preferably, the automatic calculation of MTP delay is performed as follows: ① Binarize each difference image with a binarization threshold of 9; ② ​​Calculate the number of non-zero values ​​in each binarized image; ③ When the number of non-zero values ​​in a binarized image is greater than 10, it is determined that the turntable has started to rotate, and the image number is recorded as ind1; ④ Continue to traverse subsequent images and calculate the average pixel value of each image lens region; ⑤ When the average pixel value of a certain image lens region is detected to be greater than 150, it is determined that the screen is lit up, and the image number is recorded as ind2; ⑥ End the traversal, calculate the MTP delay, and the result is (ind2-ind1) / f*1000 milliseconds (where f is the high-speed camera frame rate).

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention can reconstruct the entire process with an accuracy of 0.1ms. The testing environment is stable, ensuring the IMU is unaffected by environmental factors and reducing system errors. By adjusting a three-axis turntable, it realistically simulates the head-mounted device. A high-precision turntable is used to perform the mechanical movements. The high-precision turntable, along with the helmet, is secured to the helmet via an HMD clamp, ensuring synchronized movement between the turntable and the HMD. The high-precision turntable, HMD, and computer system form a head motion simulation system. The computer system connects to the HMD and high-precision turntable via USB to acquire real-time motion data from both. The high-precision turntable consists of a base, an outer frame, an inner frame, and corresponding motors. The three-frame position accuracy is ≤ ±5", the repeatability is ≤ ±5", and the angular velocity accuracy is 0.001° / s. The base has four adjustable height casters to adjust its parallelism to the ground during use. The turntable has a built-in high-precision angular velocity sensor system of ±5", which is far greater than the accuracy of the HMD. During use, the turntable is placed on a flat marble surface. After the setup is complete, the turntable, computer system, and HMD are turned on. The computer system first initializes the turntable (turntable self-calibration), and then the turntable and HMD synchronize their accuracy. After successful synchronization, the turntable test preparation is complete, and the turntable can then simulate the rotation of a human head in three-dimensional space. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method of the present invention;

[0021] Figure 2 This is a flowchart of the high-precision initialization process of the present invention;

[0022] Figure 3 This is a flowchart of the automatic calculation of MTP delay in this invention;

[0023] Figure 4 This is a schematic diagram of the system connection of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figure 1-4 A VR MTP testing method, the testing method includes the following steps:

[0026] A. The high-speed camera starts shooting;

[0027] B. A three-axis high-precision turntable simulates human body rotation;

[0028] C. The VR device determines whether the rotation is greater than angle a (a is less than or equal to 0.1°);

[0029] D. If no, the three-axis high-precision turntable continues to simulate human body rotation; if yes, the VR glasses begin rendering.

[0030] E. Asynchronous time warp;

[0031] F. The screen displays white;

[0032] G. The high-speed camera stops shooting;

[0033] H. Analyze and calculate the captured images.

[0034] The high-speed camera is bidirectionally connected to a PC via a 10 Gigabit Ethernet card, enabling complete transfer and storage of captured images. The network cable serves as the communication interface between the camera and the PC. Software configures the high-speed camera's parameters to meet performance requirements. The PC includes control and analysis software, calculating the MTP time by analyzing images captured by the high-speed camera. The output of the control software connects to the input of the analysis software. Another input of the high-speed camera connects to the output of a high-precision three-axis turntable. This high-precision turntable includes an HMD, HMD fixture, and a three-axis IMU+GYRO sensor. The HMD includes a display, GPU, CPU, and IMU. Simultaneously, the high-precision three-axis turntable is bidirectionally connected to another PC, which includes turntable control software responsible for simulating head movements. The HMD is fixed to the high-precision three-axis turntable using the HMD fixture. The high-precision IMU unit on the high-precision three-axis turntable performs specified motion comparisons with the HMD. The IMU unit's values ​​enable high-precision synchronization between the turntable and HMD. The HMD has a built-in APK, which triggers the HMD screen to change from black to white when the IMU detects rotation (specifically: ① HMD is installed on the turntable fixture; ② The turntable is initialized; ③ Initialization is successful; ④ If not, the turntable is initialized again; if yes, the HND and turntable IMU are synchronized; ⑤ Synchronization is successful; ⑥ If not, the HND and turntable IMU are synchronized again; if yes, the head rotation is simulated).

[0035] The test needs to be conducted under natural light (constant light) or flicker-free ambient lighting (to reduce algorithm calculation errors), and the specific test method is as follows: ① Configure the high-speed camera frame rate and start shooting; ② Initialize the high-precision turntable and simulate the rotation of a human head; ③ The HMD determines whether the threshold has been reached; ④ When the threshold is exceeded, the HMD starts rendering; ⑤ After rendering, asynchronous time warping is performed, and after the warping is completed, the data is transmitted to the screen via MIPI to complete the on-screen display; ⑥ After capturing the image, the analysis software reads and analyzes the MTP time.

[0036] High-speed cameras have a resolution greater than 800 (width) * 600 (height) pixels, a frame rate greater than 1000fps, an exposure time in the microsecond range, a zoom lens, and a field of view greater than 60°. Since the speed of storing images on a computer's hard drive cannot keep up with the frame rate of a high-speed camera, the images need to be saved to the computer's cache first, and then read from the cache and saved to the hard drive. Therefore, the computer's memory needs to be at least 32GB. When shooting, the camera's exposure time, frame rate, and pixels are configured on the computer. Then, the lens is aligned with the HMD lens, and the distance and lens focal length are adjusted to make the image on the computer clear.

[0037] The image catalog acquired by the high-speed camera is input into the image processing module. The image processing module extracts the first image in the catalog as the reference image and traverses all images in the catalog. The difference between each image and the reference image is calculated to obtain the difference image. Since the HMD lens area will also flicker when the turntable is not rotating, the lens area is removed when calculating the turntable rotation state in order to eliminate interference. Therefore, the lens area of ​​the difference image is set to 0 (since the initial positions of the turntable, HMD and camera are fixed, the position of the lens area in the image is known).

[0038] The automatic calculation method for MTP delay is as follows: ① Binarize each difference image with a binarization threshold of 9; ② ​​Calculate the number of non-zero values ​​in each binarized image; ③ When the number of non-zero values ​​in a binarized image is greater than 10, it is determined that the turntable has started rotating, and the image number is recorded as ind1; ④ Continue to traverse subsequent images and calculate the average pixel value of each image lens region; ⑤ When the average pixel value of a certain image lens region is detected to be greater than 150, it is determined that the screen is lit, and the image number is recorded as ind2; ⑥ End the traversal, calculate the MTP delay, and the result is (ind2-ind1) / f*1000 milliseconds (where f is the high-speed camera frame rate).

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of VR MTP testing, characterized by: The test method comprises the following steps: A. The high-speed camera starts shooting, the frame rate of the high-speed camera is configured and shooting is started, the resolution of the high-speed camera is greater than 800*600 pixels, the frame rate is greater than 1000 fps, the exposure time is in the order of microseconds, the lens is variable focus, and the field of view is greater than 60°; B. The three-axis high-precision turntable simulates human rotation, initializes the high-precision turntable, and simulates human head movement rotation, the high-speed camera is bidirectionally connected with a PC through a gigabit network card, the PC comprises control shooting software and analysis calculation software, the output end of the control shooting software is connected with the input end of the analysis calculation software, another input end of the high-speed camera is connected with the output end of the high-precision three-axis turntable, the high-precision three-axis turntable comprises an HMD, an HMD clamp and a three-axis IMU+GYRO sensor, the HMD comprises a display, a GPU, a CPU and an IMU, at the same time, the high-precision three-axis turntable is also bidirectionally connected with another PC, and the other PC comprises turntable control software; C. The VR device judges whether the rotation is greater than an angle a, and a is less than or equal to 0.1°; D. No, the three-axis high-precision turntable continues to simulate human rotation, and yes, the VR glasses start rendering; E. Asynchronous time distortion, time asynchronous distortion is performed after rendering, and is transmitted to the screen through MIPI after distortion is completed, and the screen is completed; F. The screen displays white; G. The high-speed camera stops shooting, and the analysis software reads and analyzes the MTP time after the picture is captured; H. The automatic calculation of the MTP delay is as follows: ①, each difference image is subjected to binaryzation processing, and the binaryzation threshold is 9; ②, the number of non-0 values of each binaryzation image is calculated; ③, when the number of non-0 values of a certain binaryzation image is greater than 10, it is determined that the turntable starts to rotate, the image serial number is recorded, and is recorded as ind1; ④, subsequent images are continuously traversed, and the pixel mean value of the lens area of each image is calculated; ⑤, when it is detected that the pixel mean value of the lens area of a certain image is greater than 150, it is determined that the screen is bright, the image serial number is recorded, and is recorded as ind2; ⑥, the traversal is ended, the MTP delay is calculated, and the result value is (ind2-ind1) / f*1000 milliseconds, wherein f is the frame rate of the high-speed camera.

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