Law enforcement scene video information recording system

Abstract

The invention relates to the technical field of video information recording, and discloses a law enforcement site video information recording system, which comprises a self-adaptive adjustment unit, a video acquisition unit, a video processing unit, a video coding unit and an encryption storage unit, in terms of video picture quality improvement, the adaptive adjustment unit monitors illumination in real time, automatically adjusts the aperture of the camera according to intensity, avoids overexposure or darkness, and can also analyze light spectrum to correct color temperature and restore real color. And the video processing unit removes noise, so that the picture is clear and interference-free. In terms of video data processing and storage, a video coding unit analyzes video frames in a blocking manner, coding is performed by adopting different resolutions according to detail richness, key area details are guaranteed by high resolution, data volume is reduced by low resolution, and step length is optimized in a quantization link; the encryption storage unit encrypts a video block by using an AES algorithm, and the key management system guarantees key security, prevents data leakage, and provides high-quality, safe and reliable video data for law enforcement.

Description

Technical Field

[0001] The present invention relates to the technical field of video information recording, and in particular to a law enforcement scene video information recording system. Background Art

[0002] There are many problems with traditional methods of video recording of law enforcement scenes.

[0003] On the one hand, during the video acquisition stage, due to the complex and changeable environment of the law enforcement scene, the lighting conditions are often difficult to control. For example, when enforcing the law outdoors, direct sunlight may cause the picture to be too bright and some areas to be overexposed, resulting in the loss of key details; while in dimly lit corners indoors or in night law enforcement scenes, the picture is prone to be dim and blurred, which seriously affects the subsequent viewing and analysis of the law enforcement scene. Moreover, the color temperature of the light at the scene is also unstable. The mixture of different light sources will cause serious color deviation of the picture, making it impossible to truly restore the color of the scene, and interfering with the accurate judgment of key information such as objects and personnel characteristics at the scene. On the other hand, the processing of the collected video data also faces challenges. The original video data usually contains a lot of noise, such as salt and pepper noise, which will appear as random bright spots or dark spots on the screen, making the video picture rough and unclear, causing visual interference to the video viewers, and is also not conducive to the accurate capture of law enforcement details.

[0004] Furthermore, as the amount of law enforcement video data continues to increase, the pressure of storage and transmission is becoming increasingly prominent. If a unified high-resolution encoding method is used for all video frames, it will not only take up a large amount of storage space, but also consume a lot of bandwidth resources during the transmission process, resulting in slow transmission and difficulty in meeting real-time requirements; but if the encoding resolution is uniformly reduced simply to save space, key details in the video will inevitably be lost, affecting the integrity and availability of law enforcement data.

[0005] To sum up, the existing law enforcement scene video recording technology is difficult to meet the current complex and changing law enforcement environment and the growing law enforcement needs. There is an urgent need for a new and comprehensive law enforcement scene video information recording system to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a law enforcement scene video information recording system to solve the technical problems raised in the background technology.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A law enforcement scene video information recording system, comprising: The adaptive adjustment unit is used to monitor the light intensity at the law enforcement scene in real time, and to perform adaptive adjustment of the camera aperture based on the real-time monitoring results, and to perform light spectrum analysis and camera color temperature correction based on the light spectrum analysis results; A video acquisition unit, used to collect video data of the law enforcement scene through a camera; A video processing unit, used for removing noise from the collected video data; A video encoding unit is used to analyze each video frame in the video data in blocks, determine the detail richness of each block area, and then perform high-resolution encoding and low-resolution encoding according to the detail richness; The encryption storage unit is used to encrypt and store the video data processed by the video processing unit and the video encoding unit.

[0008] As a further solution of the present invention: the adjustment method of the adaptive adjustment unit is as follows: Step Z1. Real-time collection of light intensity: The light intensity at the law enforcement scene is monitored in real time. The light sensor installed on the camera obtains light data based on a preset time interval and records it as L t , where t = 1, 2, ... e, e represents the number of timestamps, L t Indicates the light intensity obtained at the timestamp; Step Z2, adaptive aperture dynamic calculation: By formula: ; Calculate the adaptive aperture value F of the camera at each timestamp t : In the formula, k is a constant preset according to the optical characteristics of the camera; Among them, when the light is strong, L t The value is large, and the calculated F t If the value is small, the aperture will automatically decrease to F t value; When the light is weak, L t Small value, F t As the value increases, the aperture expands to the corresponding F t value; Step Z3, intelligent adaptation of white balance parameters: According to the color temperature of the light on site, that is, by analyzing the collected light spectrum, the proportion of red, green and blue light is determined, and the white balance parameters of the camera are adjusted accordingly; Step Z4: Real-time adjustment of color processing circuit: According to the red light color temperature correction coefficient CR, the green light color temperature correction coefficient CG, and the blue light color temperature correction coefficient CB, the color processing circuit inside the camera is adjusted in real time.

[0009] As a further solution of the present invention: the noise removal method of the video processing unit is as follows: StepY1, video frame extraction and pixel labeling: In the video data, all video frames are extracted, and then a video frame is selected; Mark each pixel in the video frame as (i, j), i=1, 2, ... n, n represents the number of columns of the pixel in the video frame, j=1, 2, ... m, m represents the number of rows of the pixel in the video frame; StepY2, target pixel neighborhood selection: Then a pixel is selected and a g×g neighborhood is taken with the pixel as the center; StepY3, obtain the gray value of the neighborhood: Then get the grayscale values ​​of all pixels in the neighborhood and mark them as H(i0, j0), i0=i-(g-1) / 2, ...i+(g-1) / 2, j0=j-(g-1) / 2, ...j+(g-1) / 2; StepY4, calculation of new gray value: Afterwards via: ; Calculate the gray value HP of all pixels in the neighborhood i0，j0 ; Then the gray value HP i0，j0 Replace the selected pixel; StepY5, pixel replacement execution: Replace each pixel in each video frame according to Step Y1 to Step Y4.

[0010] As a further solution of the present invention: the white balance parameters are determined as follows: The red light intensity in the collected light spectrum is marked as R, the green light intensity is marked as G, and the blue light intensity is marked as B; At the same time, obtain the preset standard red light intensity reference value, standard green light intensity reference value, and standard blue light intensity reference value, and mark them as Rc, Gc, and Bc respectively: Then through: ; Calculate the red light color temperature correction coefficient CR, the green light color temperature correction coefficient CG, and the blue light color temperature correction coefficient CB respectively.

[0011] As a further solution of the present invention: the block analysis method of the video encoding unit is as follows: Select a video frame and divide it into several pixel blocks. Then obtain the grayscale value of each pixel in each pixel block. Then, record the average grayscale value of each pixel in the pixel block as the block grayscale value of the pixel block and mark it as BH. i1，j1 , i1=1, 2, ... n1, n1 represents the height of the pixel block, that is, the number of vertical pixels in the pixel block, j1=1, 2, ... m1, m1 represents the width of the pixel block, that is, the number of horizontal pixels in the pixel block; Then through: ; Calculate the sum of the gradient magnitudes TS within the corresponding pixel block i1，j1 ; Then the sum of the gradient amplitudes in each pixel block TS i1，j1 Compare with the preset ladder threshold TSy: If TS i1，j1 >TSy, the video area corresponding to the corresponding pixel block is judged to have high detail richness, and it is marked as a high-resolution coding block, and a high-resolution coding method is then adopted; If TS i1，j1 ≤TSy, it is determined that the detail richness of the video area corresponding to the corresponding pixel block is low, and a low-resolution encoding method is adopted.

[0012] As a further solution of the present invention: wherein, in the quantization link of high-resolution encoding, for the high-resolution encoding block, its original quantization step size is reduced by half, and in the quantization link of low-resolution encoding, for the low-resolution encoding block, its original quantization step size is doubled.

[0013] As a further solution of the present invention: the encryption storage method of the encryption storage unit is as follows: The video data is divided into several video blocks, and then a key is generated by using the AES algorithm, and each video block is encrypted by the generated key to obtain the encrypted video block; A unique index is then generated for each key through a preset key management system, and the encrypted video blocks and their corresponding encryption key indexes are then stored in a preset storage device.

[0014] Beneficial effects of the present invention: Optimize lighting and color presentation: The adaptive adjustment unit monitors the light intensity in real time by installing a light sensor on the camera, and automatically adjusts the camera aperture size according to the light intensity to avoid overexposure due to excessive light and dimness due to insufficient light, thus ensuring the brightness of the picture. At the same time, the light spectrum is analyzed, the color temperature correction coefficient of the three-color light is calculated, and the color processing circuit inside the camera is adjusted in real time, so that the color of the output video can restore the color of the real scene, improving the overall presentation quality of the video picture from the aspects of lighting and color, which is helpful for more accurate viewing of the law enforcement scene in the future.

[0015] Reduce video noise interference: The video processing unit adopts a specific noise removal method. It extracts video frames, selects pixels and takes neighborhoods, obtains the grayscale values ​​of pixels in the neighborhood, and then calculates and replaces them. In this way, the pixels in each video frame are processed in turn, which can effectively remove noise from the video data, achieve noise smoothing of the video data, and further improve the quality of the video picture, making the picture clearer and cleaner, which is convenient for observing the details of the law enforcement scene.

[0016] Efficient coding saves space: The video coding unit analyzes each video frame in the video data in blocks, calculates the sum of the gradient amplitudes in the pixel blocks, and compares it with the preset gradient threshold to determine the detail richness of each block area, and then adopts the corresponding coding method for different richness. High-resolution coding is used for areas with high detail richness, and low-resolution coding is used for areas with low detail richness. This effectively reduces the amount of data, saves storage space, and improves the rationality and efficiency of video data coding while ensuring the integrity of key information. In addition, in the quantization stage of high-resolution and low-resolution coding, the quantization step size is adjusted specifically to further optimize the coding effect.

[0017] Ensure data security: The encryption storage unit uses the AES algorithm to generate keys to encrypt the divided video blocks, and then generates a unique index for each key through the key management system. The encrypted video blocks and their corresponding encryption key indexes are stored in specific storage devices, which strictly restricts only authorized personnel to obtain the key to decrypt and view the video through the key management system, effectively preventing the leakage of video data at the law enforcement scene, ensuring the security and confidentiality of the data, and meeting the high requirements of law enforcement for data security.

[0018] In summary, the law enforcement scene video information recording system optimizes the video collection, processing, and storage from multiple aspects, and can provide high-quality, safe and reliable law enforcement scene video materials, which is conducive to the smooth implementation of law enforcement work and subsequent retrospective analysis and other work. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] Figure 1 The present invention is a system block diagram of a law enforcement scene video information recording system.

[0021] Figure 2 It is a module flow diagram of an adaptive adjustment unit in a law enforcement scene video information recording system of the present invention.

[0022] Figure 3 It is a module flow diagram of a video processing unit in a law enforcement scene video information recording system of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1 See also Figure 1 As shown, the present invention is a law enforcement scene video information recording system, comprising: A video acquisition unit, used to collect video data of the law enforcement scene through a camera; A video encoding unit is used to analyze each video frame in the video data in blocks, determine the detail richness of each block area, and then perform high-resolution encoding and low-resolution encoding according to the detail richness; The specific method is as follows: Taking a video frame as an example, the video frame is divided into several pixel blocks, and then the grayscale value of each pixel in each pixel block is obtained. Then, the average value of the corresponding grayscale value of each pixel in the pixel block is recorded as the block grayscale value of the pixel block, and it is marked as BH. i1，j1 , i1=1, 2, ... n1, n1 represents the height of the pixel block, that is, the number of vertical pixels in the pixel block, j1=1, 2, ... m1, m1 represents the width of the pixel block, that is, the number of horizontal pixels in the pixel block; Then through: ; Calculate the sum of the gradient magnitudes TS within the corresponding pixel block i1，j1 ; Then the sum of the gradient amplitudes in each pixel block TS i1，j1 Compare with the preset ladder threshold TSy: If TS i1，j1>TSy, the video area corresponding to the corresponding pixel block is judged to have high detail richness, and it is marked as a high-resolution coding block, and a high-resolution coding method is then adopted; If TS i1，j1 ≤TSy, it is determined that the detail richness of the video area corresponding to the corresponding pixel block is low, and a low-resolution encoding method is then used to reduce the amount of data, thereby saving storage space while ensuring key information.

[0025] In the quantization phase of high-resolution coding, for a high-resolution coding block, its original quantization step size is reduced by half, and in the quantization phase of low-resolution coding, for a low-resolution coding block, its original quantization step size is doubled; An encryption storage unit, used for encrypting and storing the video data processed by the video processing unit and the video encoding unit; The method is: The video data is divided into several video blocks, and then the AES algorithm in the symmetric encryption algorithm is used to generate a 128-bit key, and then each video block is encrypted by the generated key to obtain the encrypted video block; Then, a unique index is generated for each key through the key management system, and the encrypted video blocks and their corresponding encryption key index are stored in a dedicated storage device to ensure that only authorized personnel can obtain the key to decrypt and view the video through the key management system to prevent data leakage; In this embodiment, the AES algorithm and the key management system in the symmetric encryption algorithm are both existing technologies, so they are not described in detail; In this embodiment, the video encoding unit performs block analysis on the video frame, determines the detail richness by comparing the sum of the gradient amplitude of each pixel block with the preset gradient threshold, and then adopts different resolution encoding methods. For areas with high detail richness, high-resolution encoding is used to better retain key picture details; for areas with low detail richness, low-resolution encoding is used, which effectively reduces the amount of data, saves storage space while ensuring that key information is not lost, and improves the overall encoding efficiency and storage rationality. In the quantization link of high and low resolution encoding, the quantization step size is adjusted in a targeted manner, and the encoding effect is further optimized, so that the encoding is more adapted to the characteristics of different regions. The encryption storage unit generates a 128-bit key to encrypt the video block using the AES algorithm in the symmetric encryption algorithm, and generates a unique index for each key with the help of the key management system, and stores the encrypted video block and its corresponding index in a dedicated storage device, strictly restricting data access rights. Only authorized personnel can decrypt and view the video by obtaining the key through the key management system, effectively preventing the leakage of video data and ensuring the security and confidentiality of the video data at the law enforcement site.

[0026] Embodiment 2 See also Figure 2 As shown, as the second embodiment of the present invention, when the present application is implemented, compared with the first embodiment, the technical solution of this embodiment is different from that of the first embodiment only in that the second embodiment further includes: include: The adaptive adjustment unit is used to monitor the light intensity at the law enforcement scene in real time, and to perform adaptive adjustment of the camera aperture based on the real-time monitoring results, and to perform light spectrum analysis and camera color temperature correction based on the light spectrum analysis results; The specific method is as follows: Step Z1. Real-time monitoring of light intensity at the law enforcement site: The light sensor on the camera is used to obtain light data every 0.5 seconds and record it as L t , where t = 1, 2, ... e, e represents the number of timestamps, L t Indicates the light intensity obtained at the timestamp; Step Z2, through the formula: ; Calculate the adaptive aperture value F of the camera at each timestamp t : In the formula, k is a constant preset according to the optical characteristics of the camera; In this embodiment, when the light intensity is high, L t The value is large, and the calculated F t If the value is small, the aperture will automatically decrease to F t value to prevent overexposure; When the light is weak, L t Small value, F t As the value increases, the aperture expands to the corresponding F t value to ensure the brightness of the picture; Step Z3. According to the color temperature of the light on site, that is, by analyzing the collected light spectrum, determine the proportion of red, green and blue light, and then adjust the white balance parameters of the camera as follows: The red light intensity in the collected light spectrum is marked as R, the green light intensity is marked as G, and the blue light intensity is marked as B; At the same time, obtain the preset standard red light intensity reference value, standard green light intensity reference value, and standard blue light intensity reference value, and mark them as Rc, Gc, and Bc respectively: Then through: ; Calculate the red light color temperature correction coefficient CR, the green light color temperature correction coefficient CG, and the blue light color temperature correction coefficient CB respectively; Step Z4: According to the red light color temperature correction coefficient CR, the green light color temperature correction coefficient CG, and the blue light color temperature correction coefficient CB, the color processing circuit inside the camera is adjusted in real time to restore the output video color to its true color.

[0027] In this embodiment, the adaptive adjustment unit can monitor the light intensity at the law enforcement scene in real time, obtain light data every 0.5 seconds, calculate the adaptive aperture value according to a specific formula, and automatically adjust the camera aperture size according to the light intensity. When the light is strong, the aperture is reduced to prevent overexposure of the picture, and when the light is weak, the aperture is expanded to ensure the brightness of the picture, ensuring that the light of the video picture is always in an appropriate state, thereby improving the overall visual effect of the picture. By performing spectral analysis on the collected light, the proportional relationship between the red, green, and blue lights is determined, and the color temperature correction coefficient is calculated by comparing with the pre-set standard three-color light intensity reference value, and then the color processing circuit inside the camera is adjusted in real time based on these coefficients, so that the color of the output video can more accurately restore the color of the real scene, enhance the authenticity and accuracy of the video color, and help to more accurately obtain the on-site situation when viewing the video later.

[0028] Embodiment 3 See also Figure 3 As shown, as the third embodiment of the present invention, when the present application is implemented, compared with the first and second embodiments, the technical solution of this embodiment is to combine the solutions of the first and second embodiments, and the difference between the technical solution of this embodiment and the first and second embodiments is that in this embodiment, it also includes: A video processing unit, used for removing noise from the collected video data; The method is as follows: StepY1. Extract all video frames from the video data, and then select a video frame as an example; Mark each pixel in the video frame as (i, j), i=1, 2, ... n, n represents the number of columns of the pixel in the video frame, j=1, 2, ... m, m represents the number of rows of the pixel in the video frame; Step Y2, then select a pixel point, and take a g×g neighborhood with the pixel point as the center. In this embodiment, the value of g is 3 or 5; Step Y3, then obtain the grayscale values ​​of all pixels in the neighborhood and mark them as H (i0, j0), i0 = i-(g-1) / 2, ... i+(g-1) / 2, j0 = j-(g-1) / 2, ... j+(g-1) / 2; StepY4, then pass: ; Calculate the gray value HP of all pixels in the neighborhood i0，j0 ; Then the gray value HPi0，j0 Replace the selected pixel; Step Y5, replace each pixel in each video frame according to the method of Step Y1 to Step Y4 to achieve noise smoothing of video data, so as to remove salt and pepper noise interference and improve video picture quality; This embodiment integrates the functional advantages of the first and second embodiments, and can not only achieve reasonable video encoding and efficient storage and ensure data security, but also can adaptively adjust the light intensity and color temperature of the law enforcement scene, improve the lighting effect and color reproduction of the video, and comprehensively enhance the performance of the law enforcement scene video information recording system, so that the collected video can achieve better results in data processing, storage security, and picture presentation quality, which is more conducive to the recording of the law enforcement scene situation and subsequent viewing and analysis.

[0029] Embodiment 4 As the fourth embodiment of the present invention, when the present application is implemented specifically, compared with the first, second and third embodiments, the difference between this embodiment and the first, second and third embodiments is only that in this embodiment, the technical solution of this embodiment is to combine the solutions of the above-mentioned first, second and third embodiments for implementation.

[0030] This fourth embodiment combines all the functional features of the first, second and third embodiments. After the video data is collected, noise can be removed to improve the quality of the video picture. Reasonable encoding can be used to save storage space and ensure the retention of key information. Encrypted storage is used to ensure data security. At the same time, the aperture and color temperature correction are adjusted in real time according to the on-site lighting conditions to optimize the lighting and color effects of the video picture. Overall, all aspects from the collection, processing, storage of video data to the quality of picture presentation are optimized, ensuring the efficient and high-quality operation of the law enforcement scene video information recording system to the greatest extent, and providing high-quality, reliable and safe video materials for law enforcement work.

[0031] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters and thresholds in the formula are set by technicians in this field according to actual conditions.

[0032] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A law enforcement scene video information recording system, characterized in that: Includes: Includes: The adaptive adjustment unit is used to monitor the light intensity at the law enforcement scene in real time, and to perform adaptive adjustment of the camera aperture based on the real-time monitoring results, and to perform light spectrum analysis and camera color temperature correction based on the light spectrum analysis results; A video acquisition unit, used to collect video data of the law enforcement scene through a camera; A video processing unit, used for removing noise from the collected video data; A video encoding unit is used to analyze each video frame in the video data in blocks, determine the detail richness of each block area, and then perform high-resolution encoding and low-resolution encoding according to the detail richness; The encryption storage unit is used to encrypt and store the video data processed by the video processing unit and the video encoding unit.

2. A law enforcement scene video information recording system according to claim 1, characterized in that: The adaptive adjustment of the camera aperture is as follows: Step Z1. Real-time monitoring of light intensity at the law enforcement site: The light sensor mounted on the camera obtains light data based on a preset time interval and records it as L t , where t = 1, 2, ... e, e represents the number of timestamps, L t Indicates the light intensity obtained at the timestamp; Step Z2, through the formula: ; Calculate the adaptive aperture value F of the camera at each timestamp t : Where k is a constant preset according to the optical characteristics of the camera.

3. A law enforcement scene video information recording system according to claim 2, characterized in that: in, When the light is strong, the camera aperture will automatically decrease to F t When the light is low, the camera aperture is expanded to F t value.

4. A law enforcement scene video information recording system according to claim 2, characterized in that: The camera color temperature correction method is as follows: First, according to the color temperature of the light at the scene, that is, by analyzing the collected light spectrum, the proportion of red, green and blue light is determined, and the white balance parameters of the camera are adjusted accordingly. Then, according to the red light color temperature correction coefficient CR, green light color temperature correction coefficient CG, and blue light color temperature correction coefficient CB, the color processing circuit inside the camera is adjusted in real time.

5. A law enforcement scene video information recording system according to claim 4, characterized in that: The white balance parameters are determined as follows: The red light intensity in the collected light spectrum is marked as R, the green light intensity is marked as G, and the blue light intensity is marked as B; At the same time, obtain the preset standard red light intensity reference value, standard green light intensity reference value, and standard blue light intensity reference value, and mark them as Rc, Gc, and Bc respectively: Then through: ; Calculate the red light color temperature correction coefficient CR, the green light color temperature correction coefficient CG, and the blue light color temperature correction coefficient CB respectively.

6. A law enforcement scene video information recording system according to claim 1, characterized in that: The noise removal method of the video processing unit is as follows: StepY1. Extract all video frames from the video data, and then select a video frame; Mark each pixel in the video frame as (i, j), i=1, 2, ... n, n represents the number of columns of the pixel in the video frame, j=1, 2, ... m, m represents the number of rows of the pixel in the video frame; StepY2, then select a pixel point and take a g×g neighborhood with the pixel point as the center; Step Y3, then obtain the grayscale values ​​of all pixels in the neighborhood and mark them as H (i0, j0), i0 = i-(g-1) / 2, ... i+(g-1) / 2, j0 = j-(g-1) / 2, ... j+(g-1) / 2; StepY4, then pass: ; Calculate the gray value HP of all pixels in the neighborhood i0，j0 ; Then the gray value HP i0，j0 Replace the selected pixel; Step Y5. Replace each pixel in each video frame according to the method from Step Y1 to Step Y4.

7. A law enforcement scene video information recording system according to claim 1, characterized in that: The block analysis method of the video encoding unit is as follows: Select a video frame and divide it into several pixel blocks. Then obtain the grayscale value of each pixel in each pixel block. Then, record the average grayscale value of each pixel in the pixel block as the block grayscale value of the pixel block and mark it as BH. i1，j1 , i1=1, 2, ... n1, n1 represents the height of the pixel block, that is, the number of vertical pixels in the pixel block, j1=1, 2, ... m1, m1 represents the width of the pixel block, that is, the number of horizontal pixels in the pixel block; Then through: ; Calculate the sum of the gradient magnitudes TS within the corresponding pixel block i1，j1 ; Then the sum of the gradient amplitudes in each pixel block TS i1，j1 The pixel value is compared with the preset gradient threshold value TSy, and the encoding method of each pixel block is determined according to the comparison result.

8. A law enforcement scene video information recording system according to claim 7, characterized in that: If TS i1，j1 >TSy, the video area corresponding to the corresponding pixel block is judged to have high detail richness, and it is marked as a high-resolution coding block, and a high-resolution coding method is then adopted; If TS i1，j1 ≤TSy, it is determined that the detail richness of the video area corresponding to the corresponding pixel block is low, and a low-resolution encoding method is adopted.

9. A law enforcement scene video information recording system according to claim 8, characterized in that: in, In the quantization stage of high-resolution coding, for the high-resolution coding block, its original quantization step size is reduced by half, and in the quantization stage of low-resolution coding, for the low-resolution coding block, its original quantization step size is doubled.

10. The law enforcement scene video information recording system according to claim 1, characterized in that: The encryption storage method of the encryption storage unit is as follows: The video data is divided into several video blocks, and then a key is generated by using the AES algorithm, and each video block is encrypted by the generated key to obtain the encrypted video block; A unique index is then generated for each key through a preset key management system, and the encrypted video blocks and their corresponding encryption key indexes are then stored in a preset storage device.

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