A static image incremental encoding and target area priority transmission method based on JPEG2000

Abstract

The present invention relates to a static image incremental encoding and target area priority transmission method based on JPEG2000, comprising the following steps: S1: compressing the first frame of image captured by the camera using the standard JPEG2000 lossless encoding method to generate a complete initial image data packet, and directly carrying it back to the base by copying; S2: calculating the difference image between the image frame captured subsequently and the previous frame, encoding only the difference part using JPEG2000, generating an incremental encoding data packet, and transmitting the incremental encoding data packet back to the base by communication; S3: the receiving end can reconstruct the image according to the initial frame and the incremental data packet. At the same time, a higher JPEG2000 encoding quality is given to the key target area, and the progressive transmission function of JPEG2000 is adopted. The present invention can make full use of the high compression performance of JPEG2000, and combine the technologies such as incremental encoding, target area priority encoding and progressive transmission to greatly reduce the bandwidth resources required for remote transmission of images, and meet the application requirements of remote high-definition images in extreme environments such as Antarctica.

Description

Technical Field

[0001] The invention relates to the technical field of polar scientific expeditions, and in particular to a static image incremental encoding and target area priority transmission method based on JPEG2000. Background Art

[0002] In extreme environments such as Antarctica, when taking images and videos of penguins or icebergs for scientific research purposes, high definition is required, which usually leads to the problem that the amount of image and video data is too large to be stored in real time, so the captured images and videos need to be transmitted remotely. Due to limited communication infrastructure, bandwidth resources are scarce and costly. After general compression of the captured images and videos, there are still problems of large data volume and high transmission cost.

[0003] In addition, when shooting images and videos in polar regions, the surrounding environment is usually unchanged, while the objects to be observed, such as penguins and icebergs, are relatively fixed, and the objects to be observed account for a very small proportion compared to the surrounding environment. In polar regions, there are not many moving objects, so the surrounding environment is usually unchanged. For the unchanged surrounding environment, it is unnecessary to perform high-quality compression and transmission.

[0004] As a new generation of still image compression standard, JPEG2000 has been widely used in the field of image processing and is also widely used in polar expeditions. The core algorithms of JPEG2000 include discrete wavelet transform, bit plane coding and arithmetic coding, rate distortion optimization and bitstream organization. It has the advantages of supporting lossy and lossless compression, progressive transmission of signal-to-noise ratio (SNR) and resolution, region of interest (ROI) coding and random access to bitstream. Although the existing JPEG2000 image coding technology can provide a high compression rate, it still generates a lot of transmission overhead when bandwidth is limited.

[0005] To address this problem, the industry has proposed a variety of optimization solutions. Among them, incremental coding technology reduces the amount of data by transmitting only the changed parts of the image, and has achieved good results in some application scenarios. At the same time, region of interest coding can also improve the encoding quality of key areas by targeting, and further compress edge background data while ensuring the clarity of key information. In addition, progressive transmission technology can first transmit thumbnails, and then gradually transmit high-resolution details, minimizing the amount of data transmitted each time.

[0006] However, the existing technology still has some shortcomings. The incremental encoding method cannot give priority transmission to the key target areas in the image, and the region of interest coding requires manual designation of the region of interest and lacks automation capabilities. At the same time, the existing solution has not been able to fully integrate technologies such as incremental encoding, region priority encoding and progressive transmission, and cannot achieve more comprehensive optimization.

[0007] Therefore, in extreme environments such as Antarctica, given the limited communication infrastructure, scarce and costly bandwidth resources, there is an urgent need to invent an image transmission method that can fully integrate technologies such as incremental coding, area priority coding and progressive transmission. Efficient remote transmission of high-definition static images is an urgent problem to be solved, reducing the bandwidth resources required for remote image transmission and meeting application requirements in extreme environments such as Antarctica. Summary of the invention

[0008] The present invention proposes a static image incremental coding and target area priority transmission method based on JPEG2000, which is suitable for the field of polar scientific research. It can make full use of the high compression performance of JPEG2000, combine incremental coding, target area priority coding and progressive transmission technologies, greatly reduce the bandwidth resources required for remote transmission of images, and meet the application needs of remote high-definition images in extreme environments such as Antarctica.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A static image incremental encoding and target area priority transmission method based on JPEG2000, characterized in that it comprises the following steps:

[0011] S1: The first frame of image captured by the camera is compressed using the standard JPEG2000 lossless coding method to generate a complete initial image data packet, which is directly carried back to the base by copying;

[0012] S2: for the subsequently captured image frame, calculate the difference image between the frame and the previous frame, perform JPEG2000 encoding on only the difference part, generate an incremental encoding data packet, and transmit the incremental encoding data packet back to the base;

[0013] S3: The receiving end can reconstruct the image according to the initial image data packet and the incremental encoding data packet;

[0014] Further, step S2 more specifically includes the following steps:

[0015] S21: extracting the key target area in the difference image in the current image frame in combination with the target detection algorithm;

[0016] S22: assign a higher JPEG2000 encoding quality to the key target area, and reduce the encoding quality for the difference image in the edge background area to further compress the amount of transmitted data;

[0017] S23: During the transmission of the incremental coded data packets, the high-quality coded data of the key target area is transmitted first, and then the low-quality coded data of the edge background area is transmitted.

[0018] Furthermore, during the transmission process in step S23, the progressive transmission function of JPEG2000 is used to first transmit the thumbnail and then gradually transmit the high-resolution details, thereby minimizing the amount of data transmitted each time.

[0019] Furthermore, in step S1, lossless coding compression is performed using an image compression encoder based on wavelet transform.

[0020] Furthermore, the wavelet transform-based image compression encoder includes a central control and data exchanger, 1-3 level wavelet transform drivers, a two-dimensional wavelet transform engine, a joint encoder, and two data caches: RAM_A and RAM_B.

[0021] Furthermore, the two-dimensional wavelet transform engine implements 5 / 3 wavelet transform.

[0022] Furthermore, the working order of each module of the compression encoder is controlled by the central control and data exchanger, and the working process consists of the following 6 states:

[0023] 1) Idle state: The system is in idle state, all modules are reset, and it enters the Lvl1 transformation state when waiting for the next frame to arrive;

[0024] 2) Lvl1 transformation state: The level 1 wavelet transform driver sends the image to the two-dimensional wavelet transform engine to transform the LL1, HL1, LH1, HH1 sub-bands and write them into RAM_A. At the same time, the central control and data exchanger reads the compressed code stream of the previous frame in RAM_B and outputs it.

[0025] 3) Lvl2 transformation state: The 2nd level wavelet transform driver reads the LL1 subband coefficients from RAM_A and sends them to the 2D wavelet transform engine to transform and obtain LL2, LH2, HL2, HH2 and write them into RAM_B;

[0026] 4) Lvl3 transformation state: The 3-level wavelet transform driver reads the LL2 subband coefficients from RAM_B and sends them to the 2D wavelet transform engine to transform and obtain LL3, LH3, HL3, HH3 and write them into RAM_A;

[0027] 5) Subband transfer state: The central control and data exchanger copies the LH2, HL2 and HH2 subbands from RAM_B to RAM_A, thus completing the three-level two-dimensional wavelet transform process of the image;

[0028] 6) Entropy coding state: The joint encoder cascades optimal quantization, adaptive zero-run coding and exponential Golomb coding to perform entropy coding on the three-level wavelet transform in RAM_A, and writes the encoded output codeword into RAM_B; the compression of the current image is completed and enters the Idle state.

[0029] Furthermore, in step S21, the specific steps of extracting the key target area in the image in combination with the target detection algorithm are as follows:

[0030] S211, obtaining a first frame image, and performing filtering processing on the first frame image;

[0031] S212, establishing a background model;

[0032] S213, collecting the current frame, performing template matching between the background model and the current frame in alternate rows and columns, and obtaining an offset distance between the background model and the current frame;

[0033] S214, symmetrically intercepting an image area from the middle of the background model, and then obtaining a corresponding partial image of the current frame by offsetting the distance, and performing Sobel marginalization, binarization, and mutual fuzzy comparison on the two images of the background model and the current frame;

[0034] S215, analyzing the comparison results, determining whether the key target appears or moves, if so, determining the key target area, otherwise returning to step S213.

[0035] Compared with the prior art, the present invention has the following advantages and technical effects:

[0036] The static image incremental encoding and target area priority transmission method based on JPEG2000 of the present invention can make full use of the high compression performance of JPEG2000, combine technologies such as incremental encoding, target area priority encoding and progressive transmission, greatly reduce the bandwidth resources required for remote image transmission, and meet the application requirements of high-definition image remote transmission in extreme environments such as Antarctica. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a flow chart of a static image incremental encoding and target area priority transmission method based on JPEG2000 of the present invention;

[0039] Figure 2 It is a specific flow chart of step S2 of the static image incremental encoding and target area priority transmission method based on JPEG2000 of the present invention;

[0040] Figure 3 It is a structural schematic diagram of an image compression encoder based on wavelet transform of the present invention;

[0041] Figure 4 It is a schematic diagram of the working process of the compression encoder of the present invention;

[0042] Figure 5 It is a flowchart of the target detection algorithm of the present invention. DETAILED DESCRIPTION

[0043] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0045] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0046] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0047] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0048] In extreme environments such as Antarctica, when taking images and videos of penguins or icebergs for scientific research purposes, the moving targets to be observed are relatively fixed, while the surrounding environment remains basically unchanged. Therefore, after obtaining the first frame of the image captured by the camera, for the subsequent image frames, only the incremental data packets of the difference parts and key target areas can be compressed and transmitted, and the receiving end can reconstruct the image based on the initial frame and the incremental data packets.

[0049] The static image incremental encoding and target area priority transmission method based on JPEG2000 of the present invention specifically comprises the following steps:

[0050] S1: The first frame of image captured by the camera is compressed using the standard JPEG2000 lossless encoding method to generate a complete initial image data packet, which is directly carried back to the base by copying.

[0051] S2: For the subsequently captured image frames, calculate the difference image with the previous frame, perform JPEG2000 encoding on only the difference part, generate an incremental encoding data packet, and transmit the incremental encoding data packet back to the base.

[0052] S3: The receiving end can reconstruct the image based on the initial frame and incremental data packets.

[0053] In step S1, the first frame image may be an original image taken by a camera, which includes the overall environment and multiple multi-animal objects and key targets in the overall environment. The first frame image may be multiple original images taken by multiple cameras, and the multiple original images are stitched together to form the corresponding overall environment.

[0054] Since the polar environment usually remains unchanged for a whole day or even for many days, after the first frame of the image is copied and brought back to the base, it can be used as the basis for subsequent transmission of images until the shooting is completed. If the surrounding environment changes significantly, the first frame of the image needs to be re-shot and copied back to the base.

[0055] Step S2 more specifically includes the following steps:

[0056] S21: Combined with the target detection algorithm, extract the key target area in the difference image in the current image frame. Because there may be multiple difference image points in the current image frame, the key targets in the scientific survey may change and appear in these difference images, or the key targets in the scientific survey may not change and not appear in these difference images. The key targets in these scientific surveys are the objects of focus, so it is crucial to extract the key target area in the difference image.

[0057] S22: Assign a higher JPEG2000 encoding quality to the key target area, and appropriately reduce the encoding quality for the difference image of the edge background area to further compress the amount of transmitted data. Since the key target area in the difference image is an important focus in scientific investigation, a higher JPEG2000 encoding quality is assigned to the key target area, while the quality of the difference image of the edge background area can be relatively appropriately reduced to further compress the amount of transmitted data.

[0058] S23: During the transmission of the incremental coded data packets, the high-quality coded data of the key target area is transmitted first, and then the low-quality coded data of the edge background area is transmitted.

[0059] During the transmission process in step S23, the progressive transmission function of JPEG2000 may be used to first transmit thumbnails and then gradually transmit high-resolution details, thereby minimizing the amount of data transmitted each time.

[0060] Through the progressive transmission of JPEG2000, you can first see the general appearance of the image, and then the image details will continue to increase rapidly until the clearest image is obtained, shortening the waiting time. This progressive transmission mode with increasing quality is particularly effective when used in a low-bandwidth network environment.

[0061] In step S1, the standard JPEG2000 lossless encoding method is used for compression to generate a complete initial image data packet, specifically:

[0062] The image compression encoder based on wavelet transform is used for lossless coding compression. The compression encoder is an embeddable compression IP core. When used, it directly receives uncompressed camera image data, compresses these data and writes them into the subsequent recording device. Since the compression encoder can guarantee more than 10 times data compression for general images under the premise of good image quality, it can effectively extend the recording time of the recording device and reduce the transmission bandwidth.

[0063] The image compression encoder based on wavelet transform includes a central control and data exchanger, 1-3 level wavelet transform drivers, a two-dimensional wavelet transform engine, a joint encoder and two data caches: RAM_A and RAM_B; firstly, the original image is subjected to wavelet transform using 1-3 level wavelet transform drivers and a two-dimensional wavelet transform engine, and then the image wavelet coefficients are entropy encoded using the joint encoder, and finally a compressed code stream is obtained, thereby achieving the purpose of image JPEG2000 lossless coding compression.

[0064] Preferably, the two-dimensional wavelet transform engine implements 5 / 3 wavelet transform. The 5 / 3 wavelet transform can remove redundancy between image pixels. The 5 / 3 wavelet transform based on the lifting structure mainly includes two operations: prediction and update.

[0065] Due to the block smoothing characteristics of natural images, there will be many all-zero areas in the high-frequency subband of the wavelet coefficients after quantization. If the coefficients are encoded separately, the coding efficiency will inevitably be very low. In order to improve the coding efficiency, context-dependent high-order coding must be used to approximate its high-order entropy. To this end, adaptive zero-run coding is used as a high-order expansion tool. The run-length coding includes two modes: normal mode and zero-run mode. During coding, forward adaptive modeling is performed and switched between the two modes. The rules are as follows: the initial mode is the normal mode, in which the input samples are directly output. If 2 consecutive 0s are input, the zero-run mode is entered; there is no output in the zero-run mode, only the number of 0s is counted, until the input is non-0, it returns to the normal mode, and the number of zero runs and the non-zero samples are output. Finally, the exponential Golomb coding with coding parameter k=0 is used to entropy encode the samples and run lengths generated by the adaptive zero run to complete the image compression and obtain the compressed image code stream.

[0066] The working order of each module of the compression encoder is controlled by the central control and data exchanger. Each level of wavelet transform uses a two-dimensional wavelet transform engine in time-sharing mode to save hardware overhead. The working process of the system consists of the following six states:

[0067] 1) Idle state: The system is in idle state, all modules are reset, and it enters the Lvl1 transformation state when waiting for the next frame to arrive;

[0068] 2) Lvl1 transformation state: The level 1 wavelet transform driver sends the image to the two-dimensional wavelet transform engine to transform the LL1, HL1, LH1, HH1 sub-bands and write them into RAM_A. At the same time, the central control and data exchanger reads the compressed code stream of the previous frame in RAM_B and outputs it.

[0069] 3) Lvl2 transformation state: The 2nd level wavelet transform driver reads the LL1 subband coefficients from RAM_A and sends them to the 2D wavelet transform engine to transform and obtain LL2, LH2, HL2, HH2 and write them into RAM_B;

[0070] 4) Lvl3 transformation state: The 3-level wavelet transform driver reads the LL2 subband coefficients from RAM_B and sends them to the 2D wavelet transform engine to transform and obtain LL3, LH3, HL3, HH3 and write them into RAM_A;

[0071] 5) Subband transfer state: The central control and data exchanger copies the LH2, HL2 and HH2 subbands from RAM_B to RAM_A, thus completing the three-level two-dimensional wavelet transform process of the image;

[0072] 6) Entropy coding state: The joint encoder cascades optimal quantization, adaptive zero-run coding and exponential Golomb coding to perform entropy coding on the three-level wavelet transform in RAM_A, and writes the encoded output codeword into RAM_B; the compression of the current image is completed and enters the Idle state.

[0073] In step S21, the specific steps of extracting the key target area in the image in combination with the target detection algorithm are as follows:

[0074] S211, obtaining a first frame image, and performing filtering processing on the first frame image;

[0075] S212, establishing a background model;

[0076] S213, collecting the current frame, performing template matching between the background model and the current frame in alternate rows and columns, and obtaining an offset distance between the background model and the current frame;

[0077] S214, symmetrically intercepting an image area from the middle of the background model, and then obtaining a corresponding partial image of the current frame by offsetting the distance, and performing Sobel marginalization, binarization, and mutual fuzzy comparison on the two images of the background model and the current frame;

[0078] S215, analyzing the comparison results, determining whether the key target appears or moves, if so, determining the key target area, otherwise returning to step S213.

[0079] This method can make full use of the high compression performance of JPEG2000, combined with technologies such as incremental coding, target area priority coding and progressive transmission, to significantly reduce the bandwidth resources required for image transmission. It is very suitable for high-definition image remote transmission applications in extreme environments such as Antarctica.

[0080] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A static image incremental coding and target area priority transmission method based on JPEG2000, suitable for scientific research in polar regions, by integrating incremental coding, area priority coding and progressive transmission, reducing the bandwidth resources required for remote image transmission, meeting the application needs of polar regions, characterized by: The following steps are involved: S1: The first frame of image captured by the camera is compressed using the standard JPEG2000 lossless coding method to generate a complete initial image data packet, which is directly carried back to the base by copying; S2: for the subsequently captured image frame, calculate the difference image between the frame and the previous frame, perform JPEG2000 encoding on only the difference part, generate an incremental encoding data packet, and transmit the incremental encoding data packet back to the base; S3: The receiving end reconstructs the image according to the initial image data packet and the incremental data packet; Wherein, step S2 comprises the following steps: S21: extracting the key target area in the difference image in the current image frame in combination with the target detection algorithm; S22: assign a higher JPEG2000 encoding quality to the key target area, and reduce the encoding quality for the difference image in the edge background area to further compress the amount of transmitted data; S23: during the transmission of the incremental coded data packet, the high-quality coded data of the key target area is transmitted first, and then the low-quality coded data of the edge background area is transmitted; During the transmission process in step S23, the progressive transmission function of JPEG2000 is adopted to first transmit the thumbnail and then gradually transmit the high-resolution details, thereby minimizing the amount of data transmitted each time.

2. The method for incremental encoding and target area priority transmission of static images based on JPEG2000 according to claim 1, characterized in that: In step S1, lossless coding compression is performed using an image compression encoder based on wavelet transform.

3. The method for incremental encoding and target area priority transmission of static images based on JPEG2000 according to claim 2, characterized in that: The image compression encoder based on wavelet transform includes a central control and data exchanger, 1-3 level wavelet transform drivers, 2D wavelet transform engine, joint encoder and two data buffers: RAM_A and RAM_B.

4. The method for incremental encoding and target area priority transmission of static images based on JPEG2000 according to claim 3, characterized in that: The two-dimensional wavelet transform engine implements 5 / 3 wavelet transform.

5. The method for incremental encoding and target area priority transmission of static images based on JPEG2000 according to claim 4, characterized in that: The working order of each module of the compression encoder is controlled by the central control and data exchanger. The working process consists of the following 6 states: 1) Idle state: The system is in idle state, all modules are reset, and it enters the Lvl1 transformation state when waiting for the next frame to arrive; 2) Lvl1 transformation state: The level 1 wavelet transform driver sends the image to the two-dimensional wavelet transform engine to transform the LL1, HL1, LH1, HH1 sub-bands and write them into RAM_A. At the same time, the central control and data exchanger reads the compressed code stream of the previous frame in RAM_B and outputs it. 3) Lvl2 transformation state: The 2nd level wavelet transform driver reads the LL1 subband coefficients from RAM_A and sends them to the 2D wavelet transform engine to transform and obtain LL2, LH2, HL2, HH2 and write them into RAM_B; 4) Lvl3 transformation state: The 3-level wavelet transform driver reads the LL2 subband coefficients from RAM_B and sends them to the 2D wavelet transform engine to transform and obtain LL3, LH3, HL3, HH3 and write them into RAM_A; 5) Subband transfer state: The central control and data exchanger copies the LH2, HL2 and HH2 subbands from RAM_B to RAM_A, thus completing the three-level two-dimensional wavelet transform process of the image; 6) Entropy coding state: The joint encoder cascades optimal quantization, adaptive zero-run coding and exponential Golomb coding to perform entropy coding on the three-level wavelet transform in RAM_A, and writes the encoded output codeword into RAM_B; the compression of the current image is completed and enters the Idle state.

6. The method for incremental encoding and target area priority transmission of static images based on JPEG2000 according to claim 1, characterized in that: In step S21, the specific steps of extracting the key target area in the image in combination with the target detection algorithm are as follows: S211, obtaining a first frame image, and performing filtering processing on the first frame image; S212, establishing a background model; S213, collecting the current frame, performing template matching between the background model and the current frame in alternate rows and columns, and obtaining an offset distance between the background model and the current frame; S214, symmetrically intercepting an image area from the middle of the background model, and then obtaining a corresponding partial image of the current frame by offsetting the distance, and performing Sobel marginalization, binarization, and mutual fuzzy comparison on the two images of the background model and the current frame; S215, analyzing the comparison results, determining whether the key target appears or moves, if so, determining the key target area, otherwise returning to step S213.

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