WO2023230933A1 - Image compression method and apparatus, electronic device, chip and storage medium - Google Patents

Abstract

Provided in the present disclosure are an image compression method and apparatus, an electronic device, a chip and a storage medium. The method comprises: according to the data stream length of a current scanning line and the total data stream length from a first line to the current scanning line, determining a predicted data rate of the current scanning line; according to the predicted data rate, a data rate range, and compression parameters of the current scanning line, determining compression parameters of a next scanning line; and, according to the compression parameters of the next scanning line, performing compression processing on pixel data of the next scanning line. The solution of the present disclosure avoids reliance on empirical information for control of compression parameters and the data rate is limited to the data rate range, reducing data rate oscillation, allowing a more uniform compression loss, and improving the losslessness probability of a whole image. In addition, since a complex calculation process is not involved, the operation pressure of a device can be reduced.

Description

Image compression method, device, electronic equipment, chip and storage medium Technical field

The present disclosure relates to the field of image compression technology, and in particular, to an image compression method, device, electronic equipment, chip and storage medium.

Background technique

Currently, image compression methods based on the JPEG-LS standard (a static image compression standard for lossless compression of continuous tone images) require residual prediction of pixels to be compressed in adjacent scan lines based on the compression state of the current scan line, and residual prediction of the pixels to be compressed. The difference is quantized to encode and compress the quantized residual.

Since in normal mode, the scanning lines of the image need to be compressed and encoded with compression parameters determined by empirical values, and since the prediction residuals generated by different scanning lines in the image deviate to different degrees from the real values, compression using the same compression parameters will cause The length of the compressed code stream for each scan line fluctuates irregularly, causing code rate oscillations and uneven image compression loss, making it difficult to control the image quality loss after image compression.

Contents of the invention

In view of this, the present disclosure provides an image compression method, device, electronic equipment, chip and storage medium to at least solve the technical problems existing in the related technology.

According to a first aspect of an embodiment of the present disclosure, an image compression method is provided, and the method includes:

Obtain the compression parameters and code stream length of the current scan line, as well as the total length of the code stream from the first line to the current scan line;

Determine the predicted code rate of the current scan line based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate represents the compression parameters for the next scan based on the compression parameters corresponding to the current scan line. After the last scan line of the image is compressed, the final code rate of the image;

Determine the compression parameters of the next scan line according to the predicted code rate, code rate range and compression parameters of the current scan line;

According to the compression parameters of the next scanning line, the pixel data of the next scanning line is compressed.

Combined with any embodiment of the present disclosure, determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line includes:

When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.

Combined with any embodiment of the present disclosure, determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line includes:

In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.

Combined with any embodiment of the present disclosure, before determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line, the method further includes:

In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

In conjunction with any embodiment of the present disclosure, the upper limit of the current code rate range is adjusted based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line, include:

According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.

Combined with any embodiment of the present disclosure, the method further includes:

When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.

Combined with any embodiment of the present disclosure, before determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line, the method further includes:

In response to the current number of scan lines being greater than the second line number threshold, the upper limit of the current code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target. Code rate;

Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

Combined with any embodiment of the present disclosure, the method further includes:

When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.

Combined with any embodiment of the present disclosure, the method further includes:

The attenuation factor is determined according to the current scan line number and the second line number threshold.

Combined with any embodiment of the present disclosure, determining the attenuation factor based on the current number of scanning lines and the second set threshold includes:

Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.

Combined with any embodiment of the present disclosure, the method further includes:

In response to a line next to the line corresponding to the first line number threshold of the current scan line, the code rate range is determined according to the set target code rate and the set range coefficient.

According to a second aspect of the embodiment of the present disclosure, an image compression device is provided, and the device includes:

Parameter acquisition module: used to obtain the compression parameters and code stream length of the current scan line, as well as the total length of the code stream from the first line to the current scan line;

Code rate prediction module: used to determine the predicted code rate of the current scan line based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate representation is based on the current scan line correspondence. The final code rate of the image after compression of the next scan line to the last scan line of the image using the compression parameters;

Parameter determination module: used to determine the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line;

Compression module: used to compress the pixel data of the next scanning line according to the compression parameters of the next scanning line.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.

In connection with any embodiment of the present disclosure, before the parameter determination module determines the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the device further includes a range adjustment Module for:

In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

In conjunction with any embodiment of the present disclosure, the parameter determination module determines the current code rate range based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line. During the upper limit adjustment process, it is specifically used for:

According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.

In conjunction with any embodiment of the present disclosure, the device further includes a range limiting module for:

When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

In response to the current number of scan lines being greater than the second line number threshold, the upper limit of the current code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target. Code rate;

In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

In combination with any embodiment of the present disclosure, the device further includes a second row number threshold determination module, used for:

When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.

In conjunction with any embodiment of the present disclosure, the device further includes an attenuation factor determination module for:

The attenuation factor is determined according to the current scan line number and the second line number threshold.

Combined with any embodiment of the present disclosure, the attenuation factor determination module is specifically used in the process of determining the attenuation factor based on the current scan line number and the second line number threshold:

Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.

In conjunction with any embodiment of the present disclosure, the device further includes a range determination module for:

In response to a line next to the line corresponding to the first line number threshold of the current scan line, the code rate range is determined according to the set target code rate and the set range coefficient.

According to a third aspect of the embodiments of the present disclosure, an electronic device is provided, including:

Memory for storing instructions executable by the processor;

The processor is configured to execute executable instructions in the memory to implement the steps of the method described in any embodiment of the first aspect.

According to a fourth aspect of the embodiments of the present disclosure, there is provided a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method described in any embodiment of the first aspect are implemented.

According to a fifth aspect of an embodiment of the present disclosure, a chip is provided, including:

One or more interface circuits and one or more processors; the interface circuit is configured to receive signals from the memory of the electronic device and send the signals to the processor, where the signals include computer instructions stored in the memory; When the processor executes the computer instructions, the electronic device is caused to execute the image compression method described in any embodiment of the first aspect.

The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

Based on the compression status of the current scan line, the predicted code rate of the entire image after compressing the remaining scan lines with the current compression parameters is obtained, and by setting the code rate range and combining the predicted code rate to adjust the compression parameters of the next scan line, so that each scan Each row can adjust the compression parameters of the next scanned row in time, so that the code rate after compression based on the compression parameters is controlled within the code rate range. It avoids relying on empirical information to control compression parameters, reduces code rate fluctuations, makes compression losses even and controllable, and improves the lossless probability of the entire image. In addition, since no complex calculation process is involved, the computing pressure on the device can be reduced.

It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and do not limit the present disclosure.

Description of the drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

Figure 1 is a flow chart of an image compression method according to an exemplary embodiment of the present disclosure;

Figure 2 is a flow chart of compression parameter adjustment according to an exemplary embodiment of the present disclosure;

Figure 3 is a flow chart of determining a second row number threshold according to an exemplary embodiment of the present disclosure;

Figure 4 is a comparison diagram of image compression effects according to an exemplary embodiment of the present disclosure;

Figure 5 is a schematic diagram of an image compression device according to an exemplary embodiment of the present disclosure;

FIG. 6 is a block diagram of an electronic device according to an exemplary embodiment of the present disclosure.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with aspects of the disclosure as detailed in the appended claims.

The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "the" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, the information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present disclosure, the first information may also be called second information, and similarly, the second information may also be called first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "when" or "in response to determining."

Figure 1 shows a flow chart of an image compression method according to an exemplary embodiment of the present disclosure.

In step S101, the compression parameters and code stream length of the current scanning line are obtained, as well as the total length of the code stream from the first line to the current scanning line.

The compression parameters are used to reflect the degree of compression of the image, and are negatively correlated with the code stream length and code rate of the compressed scan lines. In the current scan line, compress the pixels of the current scan line of the image using the current compression parameters to obtain the compressed code stream length of the current scan line. Similarly, during the scanning compression process from the first line of the image to the current scanning line, the image is compressed using the compression parameters corresponding to each line to obtain the total length of the code stream from the first line to the current scanning line. In the JPEG-LS standard, the quantized prediction residual is encoded by a Golomb encoder, and the compression parameters can be characterized by the quantization step size. A large quantization step indicates a high degree of compression for the current scan line, and a small quantization step indicates a low degree of compression for the current scan line. For the same scan line, the length of the code stream compressed by a larger quantization step is smaller.

In step S102, the predicted code rate of the current scan line is determined based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate represents the compression corresponding to the current scan line. The parameter is the final code rate of the image after compression from the next scan line to the last scan line of the image.

The code stream length of the current scan line and the total length of the code stream from the first line to the current scan line are used to represent the compression status of the current scan line and all historical scan lines. The predicted code rate is based on the compression status of the current scan line and the final code rate of the entire image after the remaining scan lines are compressed with the current compression parameters. In one example, the predicted code rate can be determined by formula (1):

Among them, p represents the predicted code rate, H represents the total number of lines of the image, h represents the number of currently scanned lines, which can be obtained through the current row index, Hh represents the number of remaining unscanned lines of the image, and b _line represents the current scanned line. The length of the code stream, b _total represents the total length of the code stream from the first line to the current scanning line. The numerator part of formula (1) represents the final code stream length of the entire image after compressing the remaining scan lines based on the current compression parameters.

H and W represent the number of pixels in the image based on height and width respectively, and P represents the bit width of the image, which is used to represent the amount of information in each pixel in the image. The denominator part in formula (1) represents the total information amount of the image.

The predicted code rate can be obtained by calculating the proportion of the predicted code stream length to the total amount of information in the image.

In step S103, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.

The code rate range is used to limit the fluctuation degree of the predicted code rate, which can be determined by setting a target code rate of the image or multiple experiments. The code rate range may include an upper limit and/or a lower limit of the predicted code rate. In one example, when the predicted code rate exceeds the code rate range, the predicted code rate can be increased or reduced by adjusting the compression parameters of the next scan line so that the predicted code rate returns to the code rate. rate range.

In step S104, the pixel data of the next scanning line is compressed according to the compression parameter of the next scanning line.

The compression encoding can be controlled by adjusting the compression parameters of the next scanning line to encode and compress the pixels of the next scanning line. In the JPEG-LS standard, the quantized prediction residual can be encoded by the Golomb encoder based on the adjusted quantization step size.

The scheme described in this disclosure obtains the predicted code rate of the entire image after compressing the remaining scan lines with the current compression parameters based on the compression status of the current scan line, and adjusts the code rate of the next scan line by setting the code rate range and combining it with the predicted code rate. Compression parameters enable each scan line to adjust the compression parameters of the next scan line in time, so that the code rate after compression based on the compression parameters is controlled within the code rate range. It avoids relying on empirical information or the content characteristics of the image itself to control compression parameters, reduces code rate fluctuations, makes compression losses uniform and controllable, and improves the lossless probability of the entire image. In addition, since no complex calculation process is involved, the computing pressure on the device can be reduced.

In an optional embodiment, determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line includes:

When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.

Optionally, the predicted code rate of the current scan line exceeds the upper limit of the code rate, which means that the compression degree of the current scan line is too small. You can increase the compression parameter of the next scan line, that is, increase the compression degree of the next scan line, to reduce Lower the code rate of the next scan line so that the code rate during the compression of the next scan line does not exceed the upper limit of the code rate.

Similarly, if the predicted code rate of the current scan line is lower than the lower limit of the code rate, it means that the compression degree of the current scan line is too large. You can reduce the compression parameter of the next scan line, that is, reduce the compression degree of the next scan line. The code rate of the next scan line is increased so that the code rate during the compression of the next scan line is not lower than the lower limit of the code rate.

Figure 2 shows a compression parameter adjustment flow chart disclosed in this application according to an exemplary embodiment.

In step S201, it is determined whether the predicted code rate is greater than the upper limit of the code rate.

In step S202, when the predicted code rate is greater than the upper code rate limit, it may be determined whether the current compression parameter is greater than the compression parameter threshold to determine whether the current compression process is in a regular compression mode. In one example, The compression parameter threshold can be set to 15.

In step S203, when the current compression process is in the normal compression mode, the compression parameters are increased.

In step S204, it is determined whether the predicted code rate is less than the lower limit of the code rate.

In step S205, when the predicted code rate is less than the lower limit of the code rate, it can be determined whether the current compression parameter is less than 0 to determine whether the current compression process is in the compression process, that is, whether the current compression process is in the conventional compression process. model.

In step S206, if the current compression process is in the normal compression mode, the compression parameters are reduced.

In step S207, if the predicted code rate is within the code rate range, the current compression parameters may be maintained. In addition, when the current compression mode is not in the normal compression mode, the method of maintaining the current compression parameters can also be used to wait for further processing.

In one example, the compression parameter can be increased by adding 1 to the compression parameter and decreased by decrementing the compression parameter by 1 to ensure that the compression parameter variation of adjacent scan lines is controlled at 1 or 0. , to avoid obvious compression losses in the compressed image due to sudden increases or decreases in compression parameters, thereby ensuring uniform compression intensity in the image.

The scheme described in this disclosure adjusts the compression parameters in time by comparing the predicted code rate of the current scan line with the code rate range so that the code rate of the next scan line is controlled within the code rate range. At the same time, by limiting the compression parameters every The amount of adjustment is to avoid obvious compression loss in the compressed image, thereby ensuring uniform compression intensity in the image.

In an optional embodiment, determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line includes:

In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.

Optional, because when the image has just started the scanning compression process, it is impossible to determine whether the selection of the scanning range is reasonable, and there is not enough historical information in the first few lines. If the code rate of different scanning lines of the image is due to the excessive complexity of the image, Due to large fluctuations due to objective reasons, selecting a bit rate range that is too small may cause the compression process to fail to operate normally. Therefore, before determining the bit rate range, scan lines before the first line number threshold can be scanned. For compression limited by a code rate range, the code rate range is determined based on the compression state of the image. In one example, the first line number threshold is 10.

In one example, in response to the current scan line being a next line corresponding to the first line number threshold, the code rate range is determined according to the set target code rate and the set range coefficient.

The set target bit rate represents the final bit rate that the user hopes to compress the current image. The set range coefficient may be determined based on the compression state of the scan lines before the first line number threshold. For example, a set target code rate of 110% is determined as the upper limit of the code rate, and a set code rate range of 95% is determined as the lower limit of the code rate to ensure that the code rate during the image compression process always surrounds the set code rate. Target code rate fluctuations.

The scheme described in this disclosure first performs compression without code rate range restrictions on the first line number threshold and the scanning lines before it, and then determines the code rate range according to the compression state of the image to ensure the compression range. Choose wisely. In addition, the code rate range is determined according to the target set code rate and the range coefficient to ensure that the code rate during the image compression process always fluctuates around the set target code rate.

In an optional embodiment, before determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line, the method further includes:

In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

Optionally, when the current number of scan lines is greater than the first line number threshold, there are several historical scan lines before the current scan line, and the prediction of at least two scan lines before the current scan line can be used. The code rate and the predicted code rate of the current scan line are obtained, the predicted code rate change trend of the most recent scan lines is obtained, and the code rate range is adaptively adjusted according to the change trend.

In an example, specific code rate range adjustment methods include:

According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.

Optionally, in the process of image compression based on the JPEG-LS standard, due to the small oscillation of the code rate, the overall predicted code rate changes as the number of lines increases, usually showing a W-type or M-type, that is, the prediction at the Nth scanning line When the code rate is less than the predicted code rate of the adjacent scan line, the predicted code rate of the N+1th scan line is greater than the predicted code rate of the adjacent scan line. The most recent scan can be determined by the change trend of the predicted code rate of the adjacent scan lines. Part of the code rate change trend. In the case where the predicted code rate to be detected is determined based on the current scanning line and its two previous scanning lines, the two predicted code rates corresponding to the current scanning line and its two preceding lines can be determined as the to-be-detected Predicted code rate; when determining the predicted code rate to be detected based on the current scanning line and its first five scanning lines, the current scanning line and the three predictions corresponding to the first two lines and the first four lines can be The code rate is determined as the predicted code rate to be detected, or the three predicted code rates corresponding to the first row, the first three rows and the first five rows from the current scan line are determined as the predicted code rate to be detected, and the code rate is determined according to the predicted code rate to be detected. The increase or decrease trend of the predicted code rate is detected to determine the adjustment method for the upper limit of the code rate. In one example, the predicted code rates corresponding to the first five scan lines adjacent to the current scan line can be fixedly determined as the predicted code rate to be detected, and after the scanning compression of the current scan line is completed, the code rate can be automatically moved to the next line. In the selection range of the historical scan lines, the predicted code rates corresponding to the first five scan lines of the next scan line are determined as the predicted code rates to be detected.

When the predicted code rate increases sequentially, it means that the code rate of the recently scanned part shows an increasing trend, which indirectly indicates that the currently scanned part is a complex texture area of the image. By increasing the upper limit of the code rate, it is possible to allow the current area to be processed at a higher rate. Compress with small compression parameters to allocate more bitstream length in texture-complex areas.

When the predicted code rate decreases sequentially, it means that the code rate of the most recently scanned part is on a downward trend, which indirectly indicates that the currently scanned part is a simple texture area of the image. By lowering the upper limit of the code rate, it is possible to allow the current area to be processed with a higher rate. Compress with large compression parameters to allocate less bitstream length in simple texture areas.

The scheme described in this disclosure adaptively adjusts the code rate range according to the code rate change trend of the most recent scan lines, so that during the compression process, more code stream lengths are allocated in complex texture areas and less code stream lengths are allocated in simple texture areas. The length of the code stream reduces the bit rate oscillation during the encoding process, thereby achieving a reasonable distribution of the code stream during the encoding process and achieving a uniform and excessive effect of reconstructed image quality.

In an optional embodiment, the method further includes:

When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.

Optionally, although in the aforementioned method, the code rate range can be adaptively adjusted according to the code rate change trend of the most recent scan lines, the degree of adaptive adjustment of the code rate range should still be limited to a certain extent to avoid the code rate upper limit. Unlimited raising or lowering. You can limit the number of increases or decreases in the code rate upper limit by setting a threshold for increases and decreases, or you can also set an increase or decrease range value isomorphically to control the specific value of the upper limit of the code rate to remain within an appropriate range.

In one example, the upper limit of the code rate can be adjusted by increasing or decreasing the upper limit of the code rate by 5%, and the result of the increase or decrease in the upper limit of the code rate is marked by the flag bit f. After the upper limit is increased, f is marked as true. After the upper limit is lowered, f is marked as false, so that the upper limit of the code rate cannot be continuously increased or decreased, and can only be adjusted within the range of ±5%.

In one example, the conditions for increasing and decreasing the code rate upper limit can be expressed by formula (2) and formula (3) respectively.

Among them, P0-P4 represents the predicted code rate corresponding to the five historical scan lines adjacent to the current scan line, p represents the predicted code rate of the current scan line, rt represents the set target code rate, and l represents the upper limit distance of 100%. The offset of , and every time the adjustment condition is met, the adjustment amount is directly added to l,! f means that the upper limit of the code rate can be increased, and f means that the upper limit of the code rate can be reduced.

Furthermore, based on experimental data, the triggering conditions for increasing or decreasing the upper limit of the code rate can be further refined through the difference between the predicted code rate of the current scan line and the set target code rate or the difference between the predicted code rate to be detected.

The solution described in this disclosure limits the number of increases or decreases in the upper code rate by setting a threshold for the number of increases and a threshold for the number of decreases, or by using a range value to keep the specific value of the upper limit of the code rate within an appropriate range to avoid During the adaptive adjustment process of the upper limit of the code rate, the upper limit of the code rate can increase or decrease without restriction.

In an optional embodiment, before determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line, the method further includes:

In response to the current scan line number being greater than the second line number threshold, the current upper limit of the code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target code. Rate;

Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

Optionally, in the final stage of scan compression, the final compression code rate in the entire image compression process is constrained by gradually converging the upper limit of the code rate to the set target code rate. The attenuation factor is used to control the upper limit of the code rate to converge to a set target code rate. The second line number threshold represents the attenuation starting point in the image scanning and compression process. If the code rate upper limit passes through the adaptive adjustment stage before the attenuation starting point, the code rate upper limit is reset at the attenuation starting point. is the initial upper limit, such as the upper limit of the code rate corresponding to the next scan line of the first line number threshold.

In one example, the method further includes:

The attenuation factor is determined according to the current scan line number and the second line number threshold.

Optionally, the attenuation factor can be determined through formula (4):

decay＝pow(a,hh _st ) (4)

Among them, decay represents the attenuation factor, h represents the number of lines currently scanned, and h _st represents the second line number threshold, that is, the number of lines from which the attenuation starts. Therefore, the attenuation factor can be expressed by an exponential function with a as the base and the cumulative number of rows after the attenuation starting point as the power. Wherein, a<1, so that the attenuation factor gradually approaches 0 as the number of lines increases, so that the upper limit of the code rate gradually approaches the set target code rate as the number of lines increases. In one example, a=0.989.

According to the solution of the present disclosure, by using the attenuation factor as the offset coefficient of the upper limit of the code rate, the upper limit of the code rate gradually converges to the set target code rate, so as to constrain the final compression code rate in the entire image compression process.

In an optional embodiment, determining the attenuation factor based on the current number of scanning lines and the second set threshold includes:

Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.

Optionally, in order to facilitate hardware implementation, the attenuation factor corresponding to each scan line can be obtained by looking up the table. If the table is too large and difficult to obtain, jump point sampling can be performed by setting the step size. Points within the step size range can be calculated through the look-ahead difference between two table lookup results that are close to the table lookup value.

According to the solution of the present disclosure, by obtaining the corresponding relationship between the number of scanning lines and the attenuation factor, the attenuation factor corresponding to each scanning line is directly obtained by looking up the table, so as to further reduce the computing pressure of the device.

In an optional embodiment, the method further includes:

When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.

Figure 3 discloses a second line number threshold determination flowchart according to an exemplary embodiment of the present disclosure, where H represents the total number of lines of the image, and h _st represents the second line number threshold.

As shown in Figure 3, usually, when the total number of image lines H is greater than 1500, 3/4 of the total number of lines is determined as the second line number threshold;

In the case where the total number of lines of the image is between 1500 lines and 375 lines, the 375th line from the bottom of the image is determined as the second line number threshold;

In the case where the total number of image lines is less than 375 lines, the tenth line of the total number of image lines is determined as the second line number threshold. Further, in order to avoid that the upper limit of the code rate still cannot converge to the set target code rate at the end of the scan, it can be judged in the tenth line from the bottom of the image whether the convergence of the upper limit of the code rate can be completed based on the current attenuation factor. If If not, the attenuation factor is set to 0, and the set target bit rate is directly determined as the upper limit of the bit rate, so as to complete the convergence of the compression bit rate of the image in a timely manner.

According to the solution of the present disclosure, by determining the second line number threshold according to the total number of lines of the image, the scanning compression process is controlled to converge on the upper limit of the code rate at an appropriate convergence starting point, so as to constrain the final result of the entire image compression process. Compression code rate.

FIG. 4 shows an image compression effect comparison diagram according to an exemplary embodiment of the present disclosure.

Figure 4 takes as an example whether the bayer image is compressed by the method described in the present disclosure, which can reflect the before and after comparison effect of whether the scheme described in the present disclosure is adopted for image compression. Among them, the x-axis is the index of the number of scanning lines, and the y-axis is the actual code rate corresponding to each scanning line.

It can be seen that based on the solution of the present disclosure, the code rate oscillation during the image compression process can be significantly reduced, and the actual code rate can be converged to the target code rate faster.

In addition, since the solution described in the present disclosure does not rely on the image content itself, but only relies on the changing rules of the historical bit rate information, the effect of bit rate control can be achieved for images of different types and sizes.

Furthermore, the code rate range is adaptively adjusted according to the code rate change trend of the recent scan lines, so that during the compression process, more code stream lengths are allocated in complex texture areas and more code stream lengths are allocated in simple texture areas. , Reduce the bit rate oscillation during the encoding process, thereby achieving a uniform transition of reconstructed image quality, so that the image quality can be effectively controlled.

For the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present disclosure is not limited by the described action sequence, because according to the present disclosure, Some steps may be performed in other orders or simultaneously.

Secondly, those skilled in the art should also know that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily necessary for the present disclosure.

Corresponding to the foregoing embodiments of application function implementation methods, the present disclosure also provides embodiments of application function implementation devices and corresponding terminals.

A block diagram of an image compression device according to an exemplary embodiment of the present disclosure is shown in Figure 5. The device includes:

401. Parameter acquisition module: used to obtain the compression parameters and code stream length of the current scan line, as well as the total length of the code stream from the first line to the current scan line;

402. Code rate prediction module: used to determine the predicted code rate of the current scan line based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate representation is based on the current scan. The final code rate of the image after the compression parameters corresponding to the row compress the next scan line to the last scan line of the image;

403. Parameter determination module: used to determine the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line;

404. Compression module: configured to compress the pixel data of the next scanning line according to the compression parameters of the next scanning line.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.

In connection with any embodiment of the present disclosure, before the parameter determination module determines the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the device further includes a range adjustment Module for:

In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

In connection with any embodiment of the present disclosure, the parameter determination module determines the upper limit of the current code rate range based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line. During the adjustment process, it is specifically used for:

According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.

In conjunction with any embodiment of the present disclosure, the device further includes a range limiting module for:

When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.

Combined with any embodiment of the present disclosure, the parameter determination module is specifically used in the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range, and compression parameters of the current scan line:

In response to the current scan line number being greater than the second line number threshold, the current upper limit of the code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target code. Rate;

In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.

In combination with any embodiment of the present disclosure, the device further includes a second row number threshold determination module, used for:

When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.

In conjunction with any embodiment of the present disclosure, the device further includes an attenuation factor determination module for:

The attenuation factor is determined according to the current scan line number and the second line number threshold.

Combined with any embodiment of the present disclosure, the attenuation factor determination module is specifically used in the process of determining the attenuation factor based on the current scan line number and the second line number threshold:

Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.

In conjunction with any embodiment of the present disclosure, the device further includes a range determination module for:

In response to a line next to the line corresponding to the first line number threshold of the current scan line, the code rate range is determined according to the set target code rate and the set range coefficient.

As for the device embodiment, since it basically corresponds to the method embodiment, please refer to the partial description of the method embodiment for relevant details. The device embodiments described above are only illustrative. The units described above as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in a place, or can be distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the disclosed solution. Persons of ordinary skill in the art can understand and implement the method without any creative effort.

FIG. 6 shows a block diagram of an electronic device according to an exemplary embodiment of the present disclosure.

Please refer to FIG. 6 , which exemplarily shows a block diagram of an electronic device. For example, the device 600 may be a mobile phone, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, or the like.

Referring to Figure 6, the device 600 may include one or more of the following components: a processing component 602, a memory 604, a power supply component 606, a multimedia component 608, an audio component 610, an input/output (I/O) interface 612, a sensor component 614, and communications component 616.

Processing component 602 generally controls the overall operations of device 600, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 602 may include one or more processors 620 to execute instructions to complete all or part of the steps of the above method. Additionally, processing component 602 may include one or more modules that facilitate interaction between processing component 602 and other components. For example, processing component 602 may include a multimedia module to facilitate interaction between multimedia component 608 and processing component 602.

Memory 604 is configured to store various types of data to support operations at device 600 . Examples of such data include instructions for any application or method operating on device 600, contact data, phonebook data, messages, pictures, videos, etc. Memory 604 may be implemented by any type of volatile or non-volatile storage device, or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EEPROM), Programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disk.

Power component 606 provides power to various components of device 600. Power components 606 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to device 600.

Multimedia component 608 includes a screen that provides an output interface between the device 600 and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touches, swipes, and gestures on the touch panel. The touch sensor may not only sense the boundary of a touch or slide action, but also detect the duration and pressure associated with the touch or slide action. In some embodiments, multimedia component 608 includes a front-facing camera and/or a rear-facing camera. When the device 600 is in an operating mode, such as a shooting mode or a video mode, the front camera and/or the rear camera may receive external multimedia data. Each front-facing camera and rear-facing camera can be a fixed optical lens system or have a focal length and optical zoom capabilities.

Audio component 610 is configured to output and/or input audio signals. For example, audio component 610 includes a microphone (MIC) configured to receive external audio signals when device 600 is in operating modes, such as call mode, recording mode, and speech recognition mode. The received audio signal may be further stored in memory 604 or sent via communication component 616 . In some embodiments, audio component 610 includes a speaker for outputting audio signals.

The I/O interface 612 provides an interface between the processing component 602 and a peripheral interface module, which may be a keyboard, a click wheel, a button, etc. These buttons may include, but are not limited to: Home button, Volume buttons, Start button, and Lock button.

Sensor component 614 includes one or more sensors for providing various aspects of status assessment for device 600 . For example, the sensor component 614 may detect the open/closed state of the device 600, the relative positioning of components, such as the display and keypad of the device 600, the sensor component 614 may detect a change in position of the device 600 or a component of the device 600, The presence or absence of user contact with the device 600, device 600 orientation or acceleration/deceleration and temperature changes of the device 600. Sensor assembly 614 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. Sensor assembly 614 may include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor component 614 may include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

Communication component 616 is configured to facilitate wired or wireless communication between apparatus 600 and other devices. The device 600 can access a wireless network based on a communication standard, such as WiFi, 2G or 3G, 4G or 5G or a combination thereof. In one exemplary embodiment, the communication component 616 receives broadcast signals or broadcast related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, the communications component 616 includes a near field communications (NFC) module to facilitate short-range communications. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

In an exemplary embodiment, apparatus 600 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable Gate array (FPGA), controller, microcontroller, microprocessor or other electronic components are implemented for executing the power supply method of the above electronic device.

In an exemplary embodiment, the present disclosure provides a non-transitory computer-readable storage medium including instructions, such as a memory 604 including instructions. The instructions can be executed by the processor 620 of the device 600 to complete the power supply method of the electronic device. . For example, the non-transitory computer-readable storage medium may be ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

The present disclosure also provides a chip, which specifically includes one or more interface circuits and one or more processors. The interface circuit is used to receive signals from a memory of an electronic device and send the signals to the processor. The signals include computer instructions stored in memory. When the processor executes the computer instructions, the electronic device is caused to execute the image compression method described in any one of the disclosure. Among them, the chip can be a conventional CPU (central processing unit, central processing unit) chip, a GPU (graphics processing unit, graphics processor) chip, etc., or it can be an acceleration chip dedicated to artificial intelligence technology, such as AI (Artificial Intelligence). , artificial intelligence) accelerator, etc.

Other embodiments of the disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the disclosure that follow the general principles of the disclosure and include common knowledge or customary technical means in the technical field that are not disclosed in the disclosure. . It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise structures described above and illustrated in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the disclosure is limited only by the appended claims.

Claims (25)

1. An image compression method, characterized in that the method includes:

   Obtain the compression parameters and code stream length of the current scan line, as well as the total length of the code stream from the first line to the current scan line;

   Determine the predicted code rate of the current scan line based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate represents the compression parameters for the next scan based on the compression parameters corresponding to the current scan line. After the last scan line of the image is compressed, the final code rate of the image;

   Determine the compression parameters of the next scan line according to the predicted code rate, code rate range and compression parameters of the current scan line;

   According to the compression parameters of the next scanning line, the pixel data of the next scanning line is compressed.
2. The method of claim 1, wherein determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

   When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

   When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.
3. The method of claim 1, wherein determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

   In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.
4. The method according to claim 3, characterized in that, before determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, it also includes:

   In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

   Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

   According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.
5. The method according to claim 4, characterized in that, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line, the current code rate range is The upper limits are adjusted, including:

   According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

   When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

   When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.
6. The method of claim 5, further comprising:

   When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

   When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

   When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.
7. The method according to claim 3, characterized in that before determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, it further includes:

   In response to the current number of scan lines being greater than the second line number threshold, the upper limit of the current code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target. Code rate;

   Determining the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line includes:

   According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.
8. The method of claim 7, further comprising:

   The attenuation factor is determined according to the current scan line number and the second line number threshold.
9. The method of claim 7, wherein determining the attenuation factor based on the current number of scanning lines and the second set threshold includes:

   Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

   The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.
10. The method of claim 7, further comprising:

    When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

    When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

    When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.
11. The method according to any one of claims 3-10, characterized in that the method further includes:

    In response to a line next to the line corresponding to the first line number threshold of the current scan line, the code rate range is determined according to the set target code rate and the set range coefficient.
12. An image compression device, characterized in that the device includes:

    Parameter acquisition module: used to obtain the compression parameters and code stream length of the current scan line, as well as the total length of the code stream from the first line to the current scan line;

    Code rate prediction module: used to determine the predicted code rate of the current scan line based on the code stream length of the current scan line and the total length of the code stream from the first line to the current scan line. The predicted code rate representation is based on the current scan line correspondence. The final code rate of the image after compression of the next scan line to the last scan line of the image using the compression parameters;

    Parameter determination module: used to determine the compression parameters of the next scan line based on the predicted code rate, code rate range and compression parameters of the current scan line;

    Compression module: used to compress the pixel data of the next scanning line according to the compression parameters of the next scanning line.
13. The device according to claim 12, wherein the parameter determination module specifically uses At:

    When the predicted code rate of the current scan line is greater than the upper limit of the code rate, increase the compression parameters of the current scan line to obtain the compression parameters of the next scan line; and/or,

    When the predicted code rate of the current scan line is less than the lower limit of the code rate, the compression parameter of the current scan line is reduced to obtain the compression parameter of the next scan line.
14. The device according to claim 12, wherein the parameter determination module specifically uses At:

    In response to the current number of scan lines being greater than the first line number threshold, the compression parameters of the next scan line are determined based on the predicted code rate, the code rate range, and the compression parameters of the current scan line.
15. The device according to claim 14, characterized in that, before the parameter determination module determines the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the device Also included is a range adjustment module for:

    In response to the current number of scan lines being greater than the first line number threshold and less than or equal to the second line number threshold, based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line , adjust the upper limit of the current code rate range;

    In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

    According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.
16. The device according to claim 15, wherein the parameter determination module determines the current scan line based on the predicted code rate of at least two scan lines before the current scan line and the predicted code rate of the current scan line. During the adjustment process, the upper limit of the code rate range is specifically used for:

    According to preset rules, select the predicted code rate to be detected among the predicted code rates of at least two scan lines before the current scan line and the predicted code rate of the current scan line;

    When the predicted code rate to be detected increases sequentially, increase the upper limit of the code rate;

    When the predicted code rate to be detected decreases in sequence, the upper limit of the code rate is lowered.
17. The device according to claim 16, characterized in that the device further includes a range limiting module for:

    When the number of increases in the upper code rate exceeds a threshold of increase times, stop increasing the upper limit of the code rate; when the number of decreases in the upper limit of the code rate exceeds a threshold of decreases, stop lowering the upper limit of the code rate, or;

    When the increased code rate upper limit exceeds the increase range threshold, stop increasing the current code rate upper limit;

    When the lowered upper limit of the code rate exceeds the reduction range threshold, stop lowering the upper limit of the current bit rate.
18. The device according to claim 12, wherein the parameter determination module specifically uses At:

    In response to the current scan line number being greater than the second line number threshold, the upper limit of the current code rate range is adjusted according to the attenuation factor corresponding to the current scan line. The attenuation factor is used to control the upper limit of the code rate to converge to the set target. Code rate;

    In the process of determining the compression parameters of the next scan line based on the predicted code rate, code rate range and the compression parameters of the current scan line, the parameter determination module is specifically used to:

    According to the predicted code rate, the adjusted code rate range and the compression parameters of the current scan line, the compression parameters of the next scan line are determined.
19. The device according to claim 18, characterized in that the device further includes an attenuation factor determination module for:

    The attenuation factor is determined according to the current scan line number and the second line number threshold.
20. The device according to claim 18, wherein the attenuation factor determination module, in the process of determining the attenuation factor based on the current scan line number and the second line number threshold, is specifically used to:

    Obtain the corresponding relationship between the current scanning line number and the attenuation factor;

    The attenuation factor is obtained according to the current scanning line number and the corresponding relationship.
21. The device according to claim 18, characterized in that the device further includes a second row number threshold determination module for:

    When the total number of lines of the current image is greater than the third line number threshold, the second line number threshold is obtained based on the total number of lines and the first proportional coefficient;

    When the total number of rows of the image is less than the third row number threshold and greater than the fourth row number threshold, subtract the first preset row value from the total number of rows to obtain the second row number threshold;

    When the total number of lines of the image is less than the fourth line number threshold, the second preset line value is determined as the second line number threshold.
22. The device according to any one of claims 14 to 21, characterized in that the device further includes a range determination module for:

    In response to a line next to the line corresponding to the first line number threshold of the current scanning line, the code rate range is determined according to the set target code rate and the set range coefficient.
23. An electronic device, characterized in that the electronic device includes:

    Memory, used to store instructions executable by the processor;

    A processor configured to execute executable instructions in the memory to implement the steps of the method according to any one of claims 1 to 11.
24. A computer-readable storage medium on which a computer program is stored, characterized in that when the program is executed by a processor, the steps of the method described in any one of claims 1 to 11 are implemented.
25. A chip is characterized by including:

    One or more interface circuits and one or more processors; the interface circuit is configured to receive signals from the memory of the electronic device and send the signals to the processor, the signals including computer instructions stored in the memory; When the processor executes the computer instructions, the electronic device is caused to execute the image compression method according to any one of claims 1 to 11.

Images