A camera shooting delay test method and system

Abstract

The application discloses a camera shooting delay test method and system, and belongs to the field of photoelectric system measurement. The system comprises a synchronous trigger module, a signal generation module, a data acquisition module, a host computer, a camera and a feature matching module. Waveform signal segments with different features are constructed. The synchronous trigger module generates a rising edge pulse signal, and simultaneously triggers the signal generation module, the data acquisition module and the camera. The host computer is used for signal data processing and electric signal feature extraction, image data processing and image feature extraction, and feature template construction. The camera is controlled to shoot the signal waveform image in real time, the electric signal data and the image data are subjected to feature extraction and matching through signal analysis and image processing, the signal waveform section where the camera shooting image is located is determined, the deviation of the camera shooting delay on the image acquisition is reduced, and the measurement precision of the camera shooting delay is improved. The application is favorable for realizing high-precision fusion of multi-sensor information of an unmanned system.

Description

Technical Field

[0001] This invention relates to a method and system for testing camera shooting delay, belonging to the field of optoelectronic system measurement. Background Technology

[0002] Multi-source sensor fusion technology is a cutting-edge research direction in the field of military information. Compared with single-sensor systems, multi-sensor data fusion technology can enhance system survivability, improve the reliability and robustness of the entire system, increase data credibility and accuracy, expand the temporal and spatial coverage of the entire system, and increase the real-time performance and information utilization of the system in solving problems such as detection, tracking, and target identification. Among them, optical image data captured by cameras contains a large amount of detailed information such as geometric features, texture, and color. The technology is mature and inexpensive, and it is a common sensor in practical applications.

[0003] Camera shooting delay is an important technical indicator for evaluating camera performance. It refers to the time between receiving an external trigger signal and starting exposure to acquire an image, and it is a significant factor affecting responsiveness. When dealing with high-speed moving targets, the camera's response delay can cause a significant difference between the target's motion state at the recorded moment and the actual target motion state at the moment of shooting, making it more difficult to use the image data later.

[0004] Current methods for measuring camera delay mostly rely on electronic stopwatch displays or diode array images. With an electronic stopwatch display, the camera captures both the display and the stopwatch simultaneously in a single photograph. This results in two timestamps: the actual time displayed on the stopwatch and the time displayed on the display. The difference between these two timestamps is the camera's delay. Diode array images use a coding system to switch between displayed times in real-time, creating a millisecond timer. Both methods offer millisecond-level accuracy, which is insufficient for testing cameras with high latency requirements. Furthermore, these methods are generally limited to specific camera bands and cannot measure the delay of cameras of different models, in different bands, or with variable latency values.

[0005] Therefore, it is necessary to provide a camera shooting delay testing method and system that can quickly and accurately measure camera delay time and incorporate it as an important parameter into subsequent data processing and multi-sensor data fusion. Summary of the Invention

[0006] The main objective of this invention is to provide a method and system for testing camera shooting delay. By controlling the camera to capture signal waveform images in real time, and by using signal analysis and image processing to extract and match features from electrical signal data and image data, the measurement accuracy of camera shooting delay is improved.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] The present invention discloses a camera shooting delay testing method, comprising the following steps:

[0009] Step 1: The synchronous trigger module simultaneously triggers the signal generation module, data acquisition module, and camera. The synchronous trigger module generates a rising edge pulse signal as the trigger signal, which is then divided into three paths. One path is sent to the signal generation module, which generates an electrical signal with significant characteristics according to preset instructions. The second path is sent to the data acquisition system, which receives the electrical signal from the signal generation module in real time and displays the waveform image on the host computer. The third path is sent to the camera under test, which captures the waveform image and simultaneously transmits the image to the host computer for subsequent image processing. The electrical signal with significant characteristics consists of waveform signal segments with different features.

[0010] Preferably, the electrical signal with significant characteristics described in step one is obtained by the following method:

[0011] Using a synthetic signal generator, synthetic waveform segments with different characteristics are output by changing the frequency, amplitude, waveform, and simultaneously changing multiple parameters. Multiple different feature-coded waveforms arranged sequentially in time are switched according to preset instructions. The waveform and parameter changes are as follows: The sine waveform function is... Variable parameters A and ω; pulse wave function is The variable parameters are a, b, and k; the triangular waveform function is... The variable parameters are k and m. The waveform and parameters are switched in real time over time.

[0012] Step 2: Perform short-time Fourier transform and wavelet transform on the electrical signal with significant characteristics to achieve time-frequency analysis of the electrical signal and clearly describe the change relationship of the signal frequency over time; Fourier transform to achieve spectrum analysis of the electrical signal and obtain the distribution map of signal frequency and energy; through zero-crossing detection, search for zero-crossing points between the modulus maxima and minima of the wavelet transform within one or several scales to extract the characteristics of the electrical signal data at different time periods; at the same time, analyze waveform signal segments with different characteristics to determine the characteristic information of time-frequency, spectrum and number of zero-crossing points of different waveforms in theory; compare the theoretical characteristic information with the characteristic information of the above signal processing to remove noise and distortion generated during the generation of the electrical signal and obtain the characteristic information of signal processing.

[0013] Step 3: Process and analyze the data transmitted to the host computer. First, correct the image angle so that the waveform captured by the camera is at an angle directly facing the host computer. Then, segment the image to divide the region of interest. Finally, extract the image frequency, amplitude, waveform, and number of zero-crossing points through image recognition to obtain the image processing results.

[0014] Preferably, in step three, the electrical signal pattern is identified using a template matching model. In the template matching method, a graph is drawn based on a waveform design function as a template. The correlation coefficient of the template matching is:

[0015]

[0016] Where T(M,N) is the template, and the searched graph is S(W,H), S ij The region of the searched graph covered by the template. After the searched graph S has completed its entire search, find the subgraph S corresponding to the maximum R value. max This is the matching target. After the template and image are matched, the corresponding specific time value is found in the function to extract the image's frequency, amplitude, waveform, and number of zero-crossings, thus obtaining the image processing result.

[0017] Step 4: Perform feature matching between the electrical signal processing result obtained in Step 2 and the image processing result obtained in Step 3. By comparing the frequency, amplitude, waveform, and number of zero-crossing features, determine the signal waveform segment where the camera-captured image is located, and then calculate the camera's dynamic response delay.

[0018] This invention discloses a camera shooting delay testing system, implemented based on the aforementioned camera shooting delay testing method. The camera shooting delay testing system includes a synchronization triggering module, a signal generation module, a data acquisition module, a host computer, a camera, and a feature matching module.

[0019] The synchronous trigger module simultaneously triggers the signal generation module, data acquisition module, and camera. The synchronous trigger module generates a rising edge pulse signal as the trigger signal, which is then divided into three paths. One path is sent to the signal generation module, which generates an electrical signal with significant characteristics according to preset instructions. The second path is sent to the data acquisition system, which receives the electrical signal from the signal generation module in real time and displays the electrical signal waveform image on the host computer. The third path is sent to the camera under test, which captures the electrical signal waveform image and simultaneously transmits the image to the host computer for subsequent image processing. The host computer is used for signal data processing and electrical signal feature extraction, image data processing and image feature extraction, and feature template construction. The signal data processing and electrical signal feature extraction functions are implemented based on step two. Image data processing, image feature extraction, and feature template construction are implemented based on step three. The camera and feature matching module are implemented based on step four.

[0020] Beneficial effects:

[0021] Existing camera delay testing methods, such as those using electronic stopwatches and diodes, are mostly limited to specific camera types within a certain wavelength band and cannot meet the demands for high-precision testing. This invention discloses a camera shooting delay testing method and system. By controlling the camera to capture signal waveform images in real time, and utilizing signal analysis and image processing techniques to extract and match features from the electrical signal data and image data, high-precision testing of camera shooting delay is achieved, improving the accuracy of multi-sensor information fusion in unmanned systems. Attached Figure Description

[0022] Figure 1 Block diagram of a camera shooting delay test system;

[0023] Figure 2 This is a flowchart of a camera shooting delay testing method disclosed in this invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] like Figure 2 As shown in the figure, this embodiment discloses a camera shooting delay testing system, including a synchronization trigger module, a signal generation module, a data acquisition module, a host computer, a camera, and a feature matching module. The function of the feature matching module includes electrical signal data processing and electrical signal feature extraction, image data processing and image feature extraction, and matching of two types of features.

[0026] The synchronization trigger module simultaneously triggers the signal generation module, data acquisition module, and camera according to preset instructions. The synchronization generation module generates a rising edge pulse signal as the trigger signal, which is then divided into three paths. One path is sent to the signal generation module, which generates an electrical signal with significant characteristics according to the preset instructions. The second path is sent to the data acquisition system, which receives the electrical signal from the signal generation module in real time and displays the electrical signal waveform image in the host computer control software. The third path is sent to the camera under test, which then captures the composite signal waveform pattern with significant time-domain characteristics, and simultaneously transmits the image to the host computer for subsequent image processing.

[0027] like Figure 1 As shown in the figure, the specific implementation steps of the camera shooting delay test method disclosed in this embodiment are as follows:

[0028] Step 1: Based on the aforementioned camera shooting delay testing system, a synthetic signal generator is used to output synthetic waveform segments with different characteristics by changing the frequency, amplitude, waveform, and simultaneously changing multiple parameters. Multiple different feature-encoded waveforms arranged sequentially in time are switched according to preset instructions. Common waveforms and parameter changes are as follows: The sine waveform function is... Variable parameters A and ω; pulse wave function is The variable parameters are a, b, and k; the triangular waveform function is... The variable parameters are k and m. The waveform and parameters are switched in real time over time.

[0029] Step Two: Electrical signal data processing and feature extraction are performed on the host computer. For the generated electrical signal data, time-frequency analysis is achieved through short-time Fourier transform and wavelet transform, clearly describing the frequency change relationship over time; Fourier transform is used to perform spectrum analysis, representing the frequency and energy distribution of the signal; zero-crossing detection searches for zero-crossing points between the modulus maxima and minima of the wavelet transform within one or several scales, extracting the characteristics of the electrical signal data at different time periods. Simultaneously, combined with the waveform signal design for different time periods in the self-programmed code, the specific functions are analyzed to determine the theoretical frequency, amplitude, waveform, number of zero-crossing points, and other characteristic information of different waveforms. This information is compared with the results of the above signal processing to remove noise and distortion generated during the electrical signal data generation process.

[0030] Step 3: Image data processing and feature extraction are performed on the host computer, and feature templates are constructed for matching the electrical signal processing results with the image processing results. For image data, the image angle is first corrected so that the waveform captured by the camera is at an angle directly facing the host computer; then, image segmentation is used to divide the region of interest; finally, image recognition is performed to extract feature information such as image frequency, amplitude, waveform, and number of zero crossings. When recognizing the electrical signal pattern, template matching models or neural network models can be used. In the template matching method, a graph is drawn based on the waveform design function in the programming design as a template. The correlation coefficient of the template matching is:

[0031]

[0032] Where T(M,N) is the template, and the searched graph is S(W,H), S ij The region of the searched graph covered by the template. After the searched graph S has completed its entire search, find the subgraph S corresponding to the maximum R value. max This is the matching target. Once the template and image have been matched, the corresponding time value can be found in the function.

[0033] Step 4: In the feature matching module, the electrical signal processing results and the image processing results are matched. By comparing feature information such as frequency, amplitude, waveform, and number of zero crossings, the signal waveform segment where the camera-captured image is located is found, and the dynamic response delay of the camera is calculated to improve the measurement accuracy of the camera shooting delay.

[0034] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing camera shooting delay, characterized in that: Includes the following steps, Step 1: The synchronous trigger module simultaneously triggers the signal generation module, the data acquisition module, and the camera; the synchronous trigger module generates a rising edge pulse signal as a trigger signal, and divides the trigger signal into three paths, one of which is sent to the signal generation module to generate an electrical signal with significant characteristics according to the preset instructions; The second path is sent to the data acquisition system, which receives the electrical signal from the signal generation module in real time and displays the electrical signal waveform image on the host computer; the third path is sent to the camera under test, which captures the electrical signal waveform image and transmits the image to the host computer for subsequent image processing; the electrical signal with significant characteristics is a waveform signal segment with different characteristics. Step 2: Perform short-time Fourier transform and wavelet transform on the electrical signal with significant characteristics to realize time-frequency analysis of the electrical signal and clearly describe the change relationship of the signal frequency over time; Fourier transform to realize spectrum analysis of the electrical signal and obtain the distribution map of signal frequency and energy. By using zero-crossing detection, the zero-crossing points between the modulus maxima and minima of wavelet transform are searched within one or several scales to extract the characteristics of electrical signal data at different time periods. At the same time, waveform signal segments with different characteristics are analyzed to determine the characteristic information of time frequency, spectrum and number of zero-crossing points of different waveforms in theory. The theoretical feature information is compared with the signal processing feature information mentioned above, and the noise and distortion generated during the electrical signal generation process are removed to obtain the signal processing feature information. Step 3: Process and analyze the image transmitted to the host computer. First, correct the image angle so that the waveform captured by the camera is at an angle directly facing the host computer. Then, divide the region of interest through image segmentation. Finally, extract the image frequency, amplitude, waveform, and number of zero-crossing points through image recognition to obtain the image processing results. Step 4: Perform feature matching between the electrical signal processing result obtained in Step 2 and the image processing result obtained in Step 3; by comparing the feature information of frequency, amplitude, waveform, and number of zero crossings, determine the signal waveform segment where the camera-captured image is located, and then calculate the dynamic response delay of the camera.

2. The camera shooting delay testing method as described in claim 1, characterized in that: The electrical signal with significant characteristics described in step one is obtained through the following method: Using a synthetic signal generator, by changing the frequency, amplitude, or waveform, synthetic waveform segments with different characteristics are output; multiple different feature-coded waveforms arranged sequentially in time series are switched according to preset instructions; the waveform and parameter changes are as follows: the sine waveform function is... Variable parameters A and ω; pulse wave function is The variable parameters are a, b, and k; the triangular waveform function is... The variable parameters are k and m; the waveform and parameters are switched in real time over time.

3. The camera shooting delay testing method as described in claim 2, characterized in that: In step three, the electrical signal pattern is identified using a template matching model; in the template matching method, a graph is drawn based on the waveform design function as a template; the correlation coefficient of the template matching is: Where T(M, N) is the template, and the searched graph is S(W, H), S ij The template covers the searched graph region S; after the searched graph S has completed its full search, find the subgraph S corresponding to the maximum R value. max This is the matching target; after the template and the image are matched, the corresponding specific time value is found in the function to extract the image frequency, amplitude, waveform, and number of zero crossings, and obtain the image processing result.

4. A camera shooting delay testing system, implemented based on a camera shooting delay testing method as described in claim 1, 2, or 3, characterized in that: It includes a synchronization trigger module, a signal generation module, a data acquisition module, a host computer, a camera, and a feature matching module; The synchronous triggering module simultaneously triggers the signal generation module, the data acquisition module, and the camera; The synchronous trigger module generates a rising edge pulse signal as a trigger signal, and divides the trigger signal into three paths. One path is sent to the signal generation module, which generates an electrical signal with significant characteristics according to the preset instructions. The second path is sent to the data acquisition system, which receives the electrical signal from the signal generation module in real time and displays the electrical signal waveform image on the host computer. The third path is sent to the camera under test, which captures the electrical signal waveform image and transmits the image to the host computer for subsequent image processing. The host computer is used for signal data processing and electrical signal feature extraction, image data processing and image feature extraction, and feature template construction. The signal data processing and electrical signal feature extraction functions are implemented based on step two. The image data processing, image feature extraction, and feature template construction are implemented based on step three. The camera and feature matching module are implemented based on step four.

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