WO2022252488A1

WO2022252488A1 - Image compression method and apparatus, electronic device, and readable storage medium

Info

Publication number: WO2022252488A1
Application number: PCT/CN2021/127411
Authority: WO
Inventors: 魏红杨; 张贞雷; 于锦辉; 袁秀阳; 宋金凤
Original assignee: 苏州浪潮智能科技有限公司
Priority date: 2021-06-02
Filing date: 2021-10-29
Publication date: 2022-12-08
Also published as: CN113068040A

Abstract

The present application discloses an image compression method and apparatus, an electronic device, and a computer-readable storage medium. The method comprises: acquiring an image to be compressed and performing block processing on the image to be compressed, so as to obtain a plurality of image blocks; comparing the image blocks and corresponding historical image blocks to obtain comparison results; updating corresponding target historical image blocks for different target image blocks by using the comparison results, and encoding the target image blocks to obtain target code; and generating, by using the target code and a preset code, compressed data corresponding to the image to be compressed. In the method, each part of data to be compressed is compared with a historical image block and a changed target image block is compressed and encoded; and since the number of image blocks to be compressed and encoded is reduced, the consumption of computational resources is thus reduced; meanwhile, the time required for generating compressed data is reduced, thus reducing the delay of a video displayed on a remote terminal.

Description

Image compression method, device, electronic equipment and readable storage medium

This application claims the priority of the Chinese patent application submitted to the China Patent Office on June 2, 2021, with the application number 202110613360.9, and the title of the invention is "An Image Compression Method, Device, Electronic Equipment, and Readable Storage Medium", all of which The contents are incorporated by reference in this application.

technical field

The present application relates to the technical field of image processing, and in particular to an image compression method, an image compression device, electronic equipment, and a computer-readable storage medium.

Background technique

Baseboard Management Controller (BMC, Baseboard Management Controller) management system can provide remote display and control functions, usually through KVM (Keyboard Video Mouse, keyboard, video, mouse), which can provide real motherboard-level access. The KVM over IP solution can convert analog information such as video and control signals of the connected managed objects into digital signals, and compress them into an IP packet and transmit it through the network. The administrator can see the current information status of the managed object through the control screen of the remote terminal, and then use the local keyboard and mouse to issue a series of control commands to control the managed object.

In order to achieve the above effects, the BMC controller in the related art needs to compress each image in the obtained video stream, and send the compressed data to the remote terminal after compression, so that the remote terminal can display the video. However, image compression needs to consume more computing resources, and the number of images in the video stream is large, and the compression takes a certain amount of time. Therefore, it takes a long time for the images in the video stream to be transmitted to the remote terminal, which makes remote The video displayed by the terminal has a long delay.

Therefore, the problems of relatively large consumption of computing resources and relatively large terminal video delays in related technologies are technical problems that need to be solved by those skilled in the art.

Contents of the invention

In view of this, the purpose of this application is to provide an image compression method, image compression device, electronic equipment and computer-readable storage medium, by comparing each part of the data to be compressed with the historical image blocks, and analyzing the occurred The changed target image blocks are compressed and coded. Since the number of image blocks that need to be compressed and coded is reduced, the consumption of computing resources is reduced, and at the same time, the time delay of the video displayed by the remote terminal is reduced.

In order to solve the above technical problems, the application provides an image compression method, including:

Obtaining an image to be compressed, and performing block processing on the image to be compressed to obtain a plurality of image blocks;

comparing each of the image blocks with corresponding historical image blocks to obtain a comparison result;

Utilizing the comparison result to update the corresponding target historical image block for different target image blocks, and encoding the target image block to obtain the target code;

The compressed data corresponding to the image to be compressed is generated by using the target code and the preset code.

Optionally, also include:

Sending the compressed data and the comparison result to a remote terminal, so that the remote terminal parses the compressed data to obtain the target image block, and utilizes the historical image block and the target image block stored in the remote terminal The image block and the comparison result display the image to be compressed, and use the target image block to update the historical image block stored in the remote terminal.

Optionally, updating the corresponding target historical image blocks for different target image blocks by using the comparison results includes:

Overwriting the target historical image block in the cache with the target image block.

Optionally, said encoding the target image block to obtain the target encoding includes:

If all target historical image blocks are updated, read the target image block from the cache according to the comparison result;

Perform frequency domain transformation, quantization and coding processing on the target image block to obtain the target code.

Optionally, the generating the compressed data corresponding to the image to be compressed by using the target encoding and the preset encoding includes:

According to the comparison result, splicing the target code and the preset code to obtain initial compressed data;

Adding a file header to the initial compressed data to obtain the compressed data.

Optionally, before comparing each of the image blocks with corresponding historical image blocks, the method further includes:

judging whether the image to be compressed is the first image;

If it is the first image, then determine that all the image blocks are target image blocks;

If it is not the first image, perform the step of comparing each image block with a corresponding historical image block.

Optionally, comparing each of the image blocks with corresponding historical image blocks to obtain a comparison result includes:

judging whether each pixel in the image block is the same as the corresponding pixel data in the historical image block;

If all are the same, it is determined that the comparison result is the same;

If there is at least one pixel in the image block that is different from corresponding pixel data in the historical image block, it is determined that the comparison result is different.

The present application also provides an image compression device, including:

A block module, configured to obtain an image to be compressed, and perform block processing on the image to be compressed to obtain a plurality of image blocks;

A comparison module, configured to compare each of the image blocks with corresponding historical image blocks to obtain a comparison result;

The encoding module is used to update the corresponding target historical image block for different target image blocks by using the comparison result, and encode the target image block to obtain the target code;

A generating module, configured to generate compressed data corresponding to the image to be compressed by using the target code and the preset code.

The present application also provides an electronic device, including a memory and a processor, wherein:

The memory is used to store computer programs;

The processor is configured to execute the computer program to implement the above image compression method.

The present application also provides a computer-readable storage medium for storing a computer program, wherein the above-mentioned image compression method is implemented when the computer program is executed by a processor.

The image compression method provided by this application obtains the image to be compressed, and performs block processing on the image to be compressed to obtain multiple image blocks; compare each image block with the corresponding historical image block to obtain the comparison result; use the comparison As a result, the corresponding target historical image blocks are updated for different target image blocks, and the target image blocks are coded to obtain target codes; the compressed data corresponding to the image to be compressed is generated by using the target codes and preset codes.

It can be seen that in this method, after the image to be compressed is obtained, the entire image is not directly compressed, but is divided into blocks to obtain multiple image blocks. In the KVM application scenario, the adjacent images in the video stream usually do not change greatly, so after the image to be compressed is divided into blocks, it can be compared with the corresponding historical image block to obtain the corresponding comparison result , and determine the image block whose comparison result is different as the target image block. When the comparison results are different, it means that the information recorded in the image block has changed compared with the historical image block, so it is used to update the corresponding target historical image block for judgment during subsequent image transmission. At the same time, the target image block is encoded to complete the compression of the target image block, and the corresponding target code is obtained, so as to generate compressed data subsequently. After obtaining the target code, since the comparison result shows that there is no difference between the same image block and the historical image block, in order to reduce the consumption of computing resources, it is not necessary to encode it, but directly use the preset code to replace it, reducing the cost of the coding process. Consumed computing resources, that is, directly using the target encoding and preset encoding to generate compressed data. By comparing each part of the data to be compressed with the historical image blocks, and compressing and encoding the changed target image blocks, since the number of image blocks that need to be compressed and encoded is reduced, the consumption of computing resources is reduced At the same time, the time required for generating compressed data is reduced, the time delay of video displayed by the remote terminal is reduced, and the problems of large computing resource consumption and large terminal video time delay in related technologies are solved.

In addition, the present application also provides an image compression device, an electronic device, and a computer-readable storage medium, which also have the above beneficial effects.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or related technologies. Obviously, the accompanying drawings in the following description are only For the embodiments of the application, those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

FIG. 1 is a flow chart of an image compression method provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of an image compression and forwarding process of a related technology provided by an embodiment of the present application;

FIG. 3 is a specific image compression flowchart provided by the embodiment of the present application;

FIG. 4 is a schematic diagram of a specific image compression and forwarding process provided by the embodiment of the present application;

FIG. 5 is a schematic structural diagram of an image compression device provided in an embodiment of the present application;

FIG. 6 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments It is only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Please refer to FIG. 1 , which is a flow chart of an image compression method provided by an embodiment of the present application. The method includes:

S101: Acquire an image to be compressed, and perform block processing on the image to be compressed to obtain multiple image blocks.

The image to be compressed refers to an image that needs to be compressed to obtain corresponding compressed data. The image to be compressed can be in any data format, such as JPEG (Joint Photographic Experts Group) format, PNG (Portable Network Graphics) format, or other data formats. The number of images to be compressed is not limited, and may be one or more. When the number of images to be compressed is multiple, the sequence information among the images to be compressed will be acquired simultaneously during the process of obtaining the images to be compressed. When processing it, it needs to be processed sequentially according to the sequence information, so as to accurately determine the historical image block and the target image block subsequently.

As for the acquisition method of the image to be compressed, in one embodiment, it may be acquired from a specified storage path, and the specified storage path may be a local memory path, a hard disk path, or an external storage path. In another implementation manner, images to be compressed sent by other electronic devices or other components may be received. For example, an image to be compressed sent by a camera component, a CPU (that is, a processor) and the like may be received.

It should be noted that the images to be compressed in this embodiment are all image frames in the video stream in the KVM scenario. In the KVM application scenario, the adjacent images in the video stream usually do not change greatly, so when compressing the image, only the difference between the image to be compressed and the historical image can be compressed, thereby reducing the need for compressing the image. computing resources and time. It can be understood that if the entire image to be compressed is taken as a whole and the historical image is divided into whether there is a difference or not, then the entire image to be compressed as a whole needs to be compressed during compression, which cannot achieve the required reduction of the compressed image. The effect of computing resources and time length, so the image to be compressed needs to be divided into blocks to obtain multiple image blocks, and each image block is compared with the corresponding historical image block as a separate comparison unit.

This embodiment does not limit the specific block method of block processing. In a feasible implementation, the length and width of the image to be compressed can be detected, and the length and width of the image to be compressed can be divided according to the preset length and width. Perform equal division to obtain the length and width of each image block, and use a certain point on the image to be compressed as the origin of coordinates to divide into blocks. The origin of the coordinates may be the center point of the image to be compressed, the vertices of the four corners, and the like. In another embodiment, the size of each image block can be preset. After the image to be compressed is obtained, the image to be compressed is divided into blocks according to the preset image block size from the coordinate origin, wherein the size of each image block Can be the same or different. In addition, certain processing may be performed before or after the image is divided into blocks, such as preprocessing of data format conversion before the block, or postprocessing of data format conversion after the block. It should be noted that the block method should be fixed, that is, all images to be compressed should be sampled in the same block method for block processing.

S102: Compare each image block with a corresponding historical image block to obtain a comparison result.

In order to judge whether the content recorded in the image block has changed, there also needs to exist benchmark data for comparison with the image block, that is, the historical image block. Historical image blocks refer to image blocks used to form the latest image. The latest image refers to the latest image to be compressed before the current image to be compressed. It can be understood that, if none of the multiple images to be compressed before the current image to be compressed has changed, the historical image blocks are actually image blocks that constitute images to be compressed before multiple times.

The corresponding relationship between the image block and the historical image block refers to the corresponding positional relationship between the two in the image to be compressed. Specifically, after the image to be compressed is divided into blocks, each image block may be marked, and the specific content of the mark is related to the specific position of the image block in the image to be compressed. By marking the image block, the historical image block corresponding to the image block can be determined according to the mark during the comparison, and then it can be judged whether the recorded contents of the two are the same. As for the specific form of the mark, it may be in the form of a number, or in the form of coordinates, etc., and the specific form of the mark may be set according to actual needs.

The comparison result is used to indicate whether the content in the image block is the same as that in the historical image block. The form of the comparison result is not limited. For example, it can be in digital form, using 1 to indicate the same and 0 to indicate different; or it can be in text form. In this embodiment, the historical image blocks whose comparison results are different may be called target image blocks. In a specific implementation manner, a register group block_flag may be set, which is used to store the comparison result. block_flag[i][j] indicates the comparison result corresponding to the image block in row i and column j.

As for the specific manner of comparison, in one embodiment, the image block and the historical image block may be coded, and it is judged whether the codes corresponding to the two are the same, and if they are the same, the comparison result is determined to be the same. In another implementation manner, in order to determine the reliability and accuracy of the comparison, the pixel data of each corresponding pixel in the image block and the historical image block may be compared. Specifically, the process of comparing each image block with the corresponding historical image block to obtain the comparison result may include the following steps:

Step 11: Determine whether each pixel in the image block is the same as the corresponding pixel data in the historical image block.

Step 12: If all are the same, determine that the comparison result is the same.

Step 13: If at least one pixel in the image block is different from the corresponding pixel data in the historical image block, determine that the comparison result is different.

In this embodiment, since the image block and the historical image block are obtained by using the same block division method, they have the same number of pixels. Each pixel has corresponding pixel data, which is used to represent the state of the pixel. Depending on the specific format of the image to be compressed, the length, actual meaning, and data format of the pixel data can be different. It can be determined that there are multiple pixels in the image block, so when comparing, it is necessary to determine whether the pixel data between each pixel in the image block and the corresponding pixel in the historical image block are the same. If it is detected that any pixel in the image block is different from the corresponding pixel data in the historical image block, it can be determined that there is a difference between the two, and the comparison result is different. If all the pixels in the image block are the same as the corresponding pixel data in the historical image block, it can be determined that the comparison result is the same.

It should be noted that, in a special case, when the image to be compressed is the first frame image in the video stream, since it must be compressed, the way of comparing it with the historical image block will cause a large amount of computing resources. waste. Therefore, before using each image block to compare with the corresponding historical image block, the following steps may also be included:

Step 21: Determine whether the image to be compressed is the first image.

Step 22: If it is the first image, determine all image blocks as target image blocks.

Step 23: If it is not the first image, perform a step of comparing each image block with the corresponding historical image block.

The first image is the first image in the video stream. This embodiment does not limit the specific judgment method for judging whether the image to be compressed is the first image. In one embodiment, the image in the video stream may have a frame number. By judging whether the frame number of the image to be compressed is the minimum number In this way, it can be determined whether the image to be compressed is the first image. In another embodiment, since there is no corresponding historical image block when the image to be compressed is the first image, it may be determined whether the image to be compressed is the first image by judging whether there is a historical image block.

If the image to be compressed is not the first image, the image block can be compared with the historical image block. If the image to be compressed is the first image, it can be directly determined that all image blocks need to be compressed, so it is directly determined as the target image block for compression in subsequent steps.

S103: Utilize the comparison result to update the corresponding target historical image block for different target image blocks, and encode the target image block to obtain the target code.

After the comparison result is determined, an image block whose comparison result is different is determined as a target image block, and the target historical image block refers to a historical image block corresponding to the target image block. In order to continue to process the new image to be compressed in the future, it is necessary to use the target image block to update the corresponding target historical image block, so that when the new image to be processed is processed in the future, the historical image block can form the latest image, that is, the current image to be compressed Compress images.

Updating the target historical image block is to replace the target historical image block. The replacement referred to here, in one embodiment, may be the replacement of the content of the target historical image block, that is, directly use the target image block to cover the target history Image blocks. In another embodiment, the identity of the target historical image block can be replaced, that is, the content of the current target historical image block is not processed, but the identity of the historical image block is deprived, and the target image block is given a historical image block identity. The deprivation and endowment of identity can be carried out by deleting the mark and adding the mark. It is understandable that no matter which of the above-mentioned implementation methods is used to replace the target historical image block, the target image block needs to be stored so that it can be compared in subsequent calls. right.

Encoding the target image block refers to compressing and encoding it. The specific encoding method is not limited, and its purpose is to save storage space. Depending on the data type of the target image block, the specific encoding method can also be different. For example, Huffman coding. The specific process of encoding is not limited. For example, in one embodiment, in order to compress the target image block as much as possible, certain preprocessing may be performed on the target image block, and part of the data may be discarded. It should be noted that this embodiment does not limit the execution order of the operation of encoding the target image block and the operation of updating the historical image block, and the execution order of the two operations can be determined according to needs. Since only the target image block is encoded, the time required for encoding is greatly reduced compared with the time for encoding the entire image to be compressed, which improves the speed of image compression.

Specifically, in a feasible implementation manner, in order to reduce the occupation of storage space and increase the speed of image compression, the historical image blocks can be stored in the cache, in this case, the comparison results are different The process of updating the corresponding target historical image block of the target image block may include the following steps:

Step 31: Overwrite the target historical image block in the cache with the target image block.

By covering the target historical image block with the target image block, the update of the historical image block will not increase the occupied storage space. At the same time, by storing historical image blocks in the cache, the speed of reading and writing to them can be improved, thereby improving the speed of image compression.

Based on the above implementation manners, faults may occur in the process of encoding image blocks, such as encoding failure. In the BMC controller, each step is usually performed serially. Therefore, in order to prevent possible faults such as image block loss caused by image block encoding errors, historical image blocks can be updated first, and then encoded. Specifically, the process of encoding the target image block to obtain the target encoding may include the following steps:

Step 41: If all target historical image blocks have been updated, read the target image block from the cache according to the comparison result.

Step 42: Perform frequency domain transformation, quantization and coding processing on the target image block to obtain the target code.

In this embodiment, when all target historical image blocks have been updated, the target image block can be read from the cache according to the comparison result. It can be understood that at this moment, the target image block and the target historical image block same.

Since the human eye is not sensitive enough to high-frequency information, when encoding the target image block, the data in the high-frequency region can be discarded through a combination of frequency domain transformation and quantization to improve the performance of the compression operation. Specifically, frequency-domain transform may also be called DCT transform, and refers to a processing manner that can convert image data from time domain to frequency domain. Quantization refers to the processing method of filtering and discarding the high-frequency data in the frequency domain data, which is used in combination with the frequency domain transformation to jointly complete the deletion of high-frequency data in the target data block. Encoding specifically refers to a processing method that converts data according to the frequency of use of characters so as to save character storage space to the greatest extent. The specific method is not limited, for example, Huffman coding can be used.

S104: Generate compressed data corresponding to the image to be compressed by using the target encoding and the preset encoding.

Wherein, the preset encoding is used to fill the part corresponding to the non-target image block in the compressed data. Since the remote terminal needs to analyze the compressed data in order to display it, the compressed data must conform to the format of the normal image compressed data, so that the remote terminal can decompress it correctly, and the normal image compressed data includes the entire image to be compressed Encoding corresponding to all image blocks. In order to reduce the time required for image compression, this application does not encode the non-target image blocks. Therefore, in order to enable the remote terminal to decompress normally, the part corresponding to the non-target image blocks in the compressed data can be filled with preset encoding. The compressed data composed of target coding and preset coding conforms to the format of normal image compression data. The specific content of the preset encoding is not limited, for example, it may be an encoding of all zeros, or an encoding of all ones.

This embodiment does not limit the specific generation process of the compressed data, and the specific generation process of the compressed data may be different according to the format of the image to be compressed. In a feasible implementation manner, when the image to be compressed is in JPEG format, the process of generating compressed data corresponding to the image to be compressed by using target encoding and preset encoding may include the following steps:

Step 51: According to the comparison result, splicing the target code and the preset code to obtain the initial compressed data.

Step 52: Add a file header to the initial compressed data to obtain compressed data.

In this embodiment, the target code and the preset code can be spliced to obtain a code sequence, and the position of the target code in the code sequence corresponds to the position of the target image block in the image to be compressed. The comparison result can indicate which image block is the target image block, and the identification information (such as number) of the target image block is related to the position of the target image block in the image to be compressed, so it can be used as a basis to determine the target image block in The position in the image to compress. After the encoding sequence is obtained, a file header can be added, and the file header includes information such as an image start flag, length, and quantization table. After the file header is added, the compressed data can be obtained.

Further, since the obtained compressed data only includes the valid data corresponding to the target image block, and the valid data corresponding to the non-target image block does not exist, so the remote terminal should also store historical image blocks, so as to utilize its correlation with the target image block The image to be compressed is obtained by splicing. Correspondingly, after receiving the target image block, the remote terminal also needs to use the target image block to update the target historical image block stored in the remote terminal to ensure that subsequent images can be displayed correctly.

In one embodiment, in order to improve the reading speed of the remote terminal to the compressed data, so that it can accurately determine which parts of the compressed data are the parts corresponding to the target data block, it can send the ratio to the result. Specifically, this embodiment may also include the following steps:

Step 61: Send the compressed data and the comparison result to the remote terminal, so that the remote terminal can analyze the compressed data to obtain the target image block, use the historical image block, target image block and comparison result stored in the remote terminal to display the image to be compressed, and use The target image block updates the historical image block stored in the remote terminal.

By obtaining the comparison result, it can be determined according to the comparison result which data in the compressed data corresponds to the target image block, and restored to obtain the corresponding target image block. At the same time, based on the comparison result, the position of the target image block in the image to be compressed can be determined, and then the image to be compressed can be displayed by using it together with the historical image block and the target image block locally stored in the remote terminal. This implementation mode does not require the remote terminal to identify the preset code in the compressed data by itself, which improves the display speed, and also avoids that the target code of a certain target image block is just the same as the preset code, for example, all zero codes, In turn, the remote terminal mistakenly recognizes the target code as the remote code, causing the problem that the image to be compressed is displayed incorrectly.

By applying the image compression method provided by the embodiment of the present application, after the image to be compressed is obtained, the entire image is not directly compressed, but is divided into blocks to obtain multiple image blocks. In the KVM application scenario, the adjacent images in the video stream usually do not change greatly, so after the image to be compressed is divided into blocks, it can be compared with the corresponding historical image block to obtain the corresponding comparison result , and determine the image block whose comparison result is different as the target image block. When the comparison results are different, it means that the information recorded in the image block has changed compared with the historical image block, so it is used to update the corresponding target historical image block for judgment during subsequent image transmission. At the same time, the target image block is encoded to complete the compression of the target image block, and the corresponding target code is obtained, so as to generate compressed data subsequently. After obtaining the target code, since the comparison result shows that there is no difference between the same image block and the historical image block, in order to reduce the consumption of computing resources, it is not necessary to encode it, but directly use the preset code to replace it, reducing the cost of the coding process. Consumed computing resources, that is, directly using the target encoding and preset encoding to generate compressed data. By comparing each part of the data to be compressed with the historical image blocks, and compressing and encoding the changed target image blocks, since the number of image blocks that need to be compressed and encoded is reduced, the consumption of computing resources is reduced At the same time, the time required for generating compressed data is reduced, the time delay of video displayed by the remote terminal is reduced, and the problems of large computing resource consumption and large terminal video time delay in related technologies are solved.

Please refer to FIG. 2 . FIG. 2 is a schematic diagram of an image compression and forwarding process of a related technology provided by an embodiment of the present application. It records the whole process of compressing and forwarding the image by the BMC controller in the related art. Host computer (being CPU) after obtaining image data (in this embodiment, specifically JPEG format), image data is sent to VGA (Video Graphics Array, video graphics array) controller (process 1), and VGA controller sends video After the data is processed, it is stored in the external DDR (Double Data Rate, double-rate synchronous dynamic random access memory) (the external DDR is the unique memory space of the VGA controller), and then read from the external DDR The stored image information is read out (process 3), and then converted into a DVI (Digital Visual Interface, Digital Video Interface) signal according to the VSEA standard (Video Electronics Standards Association), and converted into an analog signal by a digital-to-analog converter Output to an external display screen through the VGA interface (process 2). The video compression controller captures image information from the DVI interface provided by the VGA controller (process 4), and then processes such as YUV conversion and JPEG image compression, and stores the compressed image data in the external DDR of the BMC system ( Steps 5 and 6, the DDR is the memory space used by the BMC system). Please refer to FIG. 3 . FIG. 3 is a specific image compression flowchart provided by the embodiment of the present application. Specifically, the image compression process in JPEG format is described, which includes the following steps:

(1) RGB2YUV: refers to the process of converting the RGB format to the YUV format to obtain the YUV image. The VGA video source data is in the RGB format, and each pixel has three base colors of red, green, and blue; the JPEG file is composed of YUV The color space to represent the color, Y represents the lightness, U and V represent the chroma. Because the human eye is more sensitive to brightness differences than to color changes, part of the chrominance information can be properly removed during sampling.

(2) 8*8block conversion: JPEG compression is performed in units of 8*8 blocks, that is, the image is divided into blocks.

(3) DCT transformation: Time domain to frequency domain conversion, which is beneficial to remove high-frequency information that has little impact on the human eye.

(4) Quantization: Combined with DCT transformation, the process of discarding high-frequency data is called quantization.

(5) Encoding: The main purpose is to maximize the saving of character (encoding) storage space according to the frequency of use. Usually Huffman coding.

(6) Add file header: include information such as image start flag, length, quantization table, etc.

The application program running on the ARM (Advanced RISC Machines, ARM processor) reads the compressed image data from the DDR used by the BMC system by calling the Ethernet controller, and transmits the remote terminal through the Ethernet (process 7, 8 ), the remote terminal decompresses the compressed data after receiving it, and displays it on the screen.

Since the above steps need to be performed on all the images, the time required for image compression is relatively long, which in turn makes the image delay on the remote terminal relatively large. Please refer to FIG. 4 , which is a schematic diagram of a specific image compression and forwarding process provided by the embodiment of the present application. The whole process includes the following steps:

(1) After the original image data obtained by the VGA controller is converted into DVI data, it is sent to the Bolck conversion module, that is, process 4.

(2) The Block conversion module is responsible for dividing the original image data into 8x8block data. For the first frame of image data (that is, the first image), the converted data is directly stored in the DDR (process 5). For the nth frame image (n>1), the transformed data is sent to the comparison module (process 6).

(3) The comparison module receives the nth frame image sent by the Block module, and takes historical image data (process 7) from the DDR, and then compares each image block of the nth frame image sent by the Block module with the taken from the DDR Compare the historical image data, that is, compare in units of blocks. At the same time, the register group block_flag is set to store the comparison result. The register size is 32 bits, and the number of registers is set according to the total number of resolution pixels divided by 64 pixels (the pixel size of a block). When the currently compared blocks are the same, set the corresponding block_flag[i][j] to 0. If not, set it as 1, and write the block data into the corresponding position in the DDR, covering the historical image data in the corresponding position (step 8).

(4) The video compression controller obtains the comparison result register group block_flag of the nth frame image data and the historical image data generated by the comparison module, and takes data from the DDR according to the comparison result. If block_flag[i][j] is 1, then Take the block data from the corresponding DDR location, if block_flag[i][j] is 0, you don't need to take the block data from the DDR.

(5) The compression process of the video compression controller is: when block_flag[i][j] is 1, then compress according to the normal process; when block_flag[i][j] is 0, DCT transformation and quantization are not required And encoding, directly determine the encoding result as a damaged encoding, and the preset encoding is specifically the result obtained by encoding an 8x8 block with all 0s. After the target image block is encoded, compressed data is generated and stored in the DDR (process 10).

(6) In the process of network transmission, it is necessary to transmit the comparison result register group block_flag data first, and then transmit the compressed data corresponding to the nth frame image.

(7) The remote terminal needs to store historical image data, decompress it after receiving the compressed data of the nth frame, and merge the decompressed nth frame data and historical data according to the received block_flag information, when block_flag[ When i][j]=1, the current block uses the image data of the nth frame, and when block_flag[i][j]=0, the current block uses the data of the historical image. Then display the merged result.

The image compression device provided by the embodiment of the present application is introduced below, and the image compression device described below and the image compression method described above can be referred to in correspondence.

Please refer to FIG. 5. FIG. 5 is a schematic structural diagram of an image compression device provided in an embodiment of the present application, including:

A block module 110, configured to obtain an image to be compressed, and perform block processing on the image to be compressed to obtain a plurality of image blocks;

A comparison module 120, configured to compare each image block with a corresponding historical image block to obtain a comparison result;

The encoding module 130 is used to update the corresponding target historical image block for different target image blocks by using the comparison result, and encode the target image block to obtain the target code;

The generating module 140 is configured to generate compressed data corresponding to the image to be compressed by using the target code and the preset code.

Optionally, also include:

The transmission module is used to send the compressed data and the comparison result to the remote terminal, so that the remote terminal analyzes the compressed data to obtain the target image block, and uses the historical image block, target image block and comparison result stored in the remote terminal to display the image to be compressed, And use the target image block to update the historical image block stored in the remote terminal.

Optionally, the coding module 130 includes:

The overwriting unit is used to overwrite the target historical image block in the cache with the target image block.

Optionally, the coding module 130 includes:

The reading unit is used to read the target image block from the cache according to the comparison result if all target historical image blocks have been updated;

The coding unit is configured to perform frequency domain transformation, quantization and coding processing on the target image block to obtain the target code.

Optionally, generating module 140 includes:

The splicing unit is used to splice the target code and the preset code according to the comparison result to obtain the initial compressed data;

The file header adding unit is used for adding a file header to the initial compressed data to obtain compressed data.

Optionally, also include:

Judging module, used to judge whether the image to be compressed is the first image;

All determination modules are used to determine that all image blocks are target image blocks if it is the first image;

Correspondingly, the comparison module 120 is a module for performing comparison between each image block and the corresponding historical image block if it is not the first image.

Optionally, the comparison module 120 includes:

A pixel data judging unit for judging whether each pixel in the image block is the same as the corresponding pixel data in the historical image block;

The same determination unit is used to determine that the comparison result is the same if all are the same;

The difference determination unit is configured to determine that the comparison result is different if at least one pixel in the image block is different from the corresponding pixel data in the historical image block.

The electronic device provided by the embodiment of the present application is introduced below, and the electronic device described below and the image compression method described above may be referred to in correspondence.

Please refer to FIG. 6 , which is a schematic structural diagram of an electronic device provided in an embodiment of the present application. The electronic device 100 may include a processor 101 and a memory 102 , and may further include one or more of a multimedia component 103 , an information input/information output (I/O) interface 104 and a communication component 105 .

Among them, the processor 101 is used to control the overall operation of the electronic device 100, so as to complete all or part of the steps in the above image compression method; the memory 102 is used to store various types of data to support the operation of the electronic device 100, these data For example, instructions for any application or method operating on the electronic device 100 may be included, as well as application-related data. The memory 102 can be realized by any type of volatile or non-volatile storage device or their combination, such as Static Random Access Memory (Static Random Access Memory, SRAM), Electrically Erasable Programmable Read-Only Memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (Read-Only Memory, One or more of Only Memory, ROM), magnetic memory, flash memory, magnetic disk or optical disk.

Multimedia components 103 may include screen and audio components. The screen can be, for example, a touch screen, and the audio component is used for outputting and/or inputting audio signals. For example, an audio component may include a microphone for receiving external audio signals. The received audio signal may be further stored in the memory 102 or sent via the communication component 105 . The audio component also includes at least one speaker for outputting audio signals. The I/O interface 104 provides an interface between the processor 101 and other interface modules, which may be a keyboard, a mouse, buttons, and the like. These buttons can be virtual buttons or physical buttons. The communication component 105 is used for wired or wireless communication between the electronic device 100 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, near field communication (Near Field Communication, NFC for short), 2G, 3G or 4G, or a combination of one or more of them, so the corresponding communication component 105 may include: Wi-Fi parts, Bluetooth parts, NFC parts.

The electronic device 100 may be implemented by one or more Application Specific Integrated Circuit (ASIC for short), Digital Signal Processor (DSP for short), Digital Signal Processing Device (DSPD for short), Programmable Logic Device (Programmable Logic Device, PLD for short), Field Programmable Gate Array (Field Programmable Gate Array, FPGA for short), controller, microcontroller, microprocessor or other electronic components are implemented for implementing the above embodiments The image compression method given.

The computer-readable storage medium provided by the embodiment of the present application is introduced below, and the computer-readable storage medium described below and the image compression method described above may be referred to in correspondence.

The present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned image compression method are implemented.

The computer-readable storage medium may include: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk, etc., which can store program codes. medium.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

Those skilled in the art can further appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the hardware and software In the above description, the components and steps of each example have been generally described according to their functions. Whether these functions are executed by means of hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may implement the described functionality using different methods for each particular application, but such implementation should not be considered as exceeding the scope of the present application.

The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be directly implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

Finally, it should also be noted that in this article, relationships such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations, any such actual relationship or order exists. Moreover, the term comprises, comprises, or any other variation is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements but also other elements not expressly listed, or Yes also includes elements inherent to such a process, method, article, or device.

In this paper, specific examples are used to illustrate the principles and implementation methods of the application. The descriptions of the above embodiments are only used to help understand the method and core idea of the application; meanwhile, for those of ordinary skill in the art, according to the application There will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be construed as limiting the application.

Claims

An image compression method, characterized in that, comprising:

Obtaining an image to be compressed, and performing block processing on the image to be compressed to obtain a plurality of image blocks;

comparing each of the image blocks with corresponding historical image blocks to obtain a comparison result;

Utilizing the comparison result to update the corresponding target historical image block for different target image blocks, and encoding the target image block to obtain the target code;

The compressed data corresponding to the image to be compressed is generated by using the target code and the preset code.
The image compression method according to claim 1, further comprising:

Sending the compressed data and the comparison result to a remote terminal, so that the remote terminal parses the compressed data to obtain the target image block, and utilizes the historical image block and the target image block stored in the remote terminal The image block and the comparison result display the image to be compressed, and use the target image block to update the historical image block stored in the remote terminal.
The image compression method according to claim 1, wherein the updating of corresponding target historical image blocks for different target image blocks using the comparison results comprises:

Overwriting the target historical image block in the cache with the target image block.
The image compression method according to claim 3, wherein said encoding the target image block to obtain the target encoding comprises:

If all target historical image blocks are updated, read the target image block from the cache according to the comparison result;

Perform frequency domain transformation, quantization and coding processing on the target image block to obtain the target code.
The image compression method according to claim 1, wherein said generating compressed data corresponding to said image to be compressed by using said target encoding and preset encoding comprises:

According to the comparison result, splicing the target code and the preset code to obtain initial compressed data;

Adding a file header to the initial compressed data to obtain the compressed data.
The image compression method according to claim 1, wherein, before comparing each of the image blocks with corresponding historical image blocks, further comprising:

judging whether the image to be compressed is the first image;

If it is the first image, then determine that all the image blocks are target image blocks;

If it is not the first image, perform the step of comparing each image block with a corresponding historical image block.
The image compression method according to claim 1, wherein said comparing each said image block with a corresponding historical image block to obtain a comparison result includes:

judging whether each pixel in the image block is the same as the corresponding pixel data in the historical image block;

If all are the same, it is determined that the comparison result is the same;

If there is at least one pixel in the image block that is different from corresponding pixel data in the historical image block, it is determined that the comparison result is different.
An image compression device, characterized in that it comprises:

A block module, configured to obtain an image to be compressed, and perform block processing on the image to be compressed to obtain a plurality of image blocks;

A comparison module, configured to compare each of the image blocks with corresponding historical image blocks to obtain a comparison result;

The encoding module is used to update the corresponding target historical image block for different target image blocks by using the comparison result, and encode the target image block to obtain the target code;

A generating module, configured to generate compressed data corresponding to the image to be compressed by using the target code and the preset code.
An electronic device, comprising a memory and a processor, wherein:

The memory is used to store computer programs;

The processor is configured to execute the computer program to realize the image compression method according to any one of claims 1-7.
A computer-readable storage medium, characterized by being used to store a computer program, wherein the computer program implements the image compression method according to any one of claims 1 to 7 when executed by a processor.