WO2016045077A1 - Image coding method and apparatus and image processing device - Google Patents

Abstract

Embodiments of the present invention provide an image coding method and apparatus and an image processing device. The coding method comprises: determining to use a palette mode for multiple pixels in a to-be-coded image area and determining to use a non-palette mode for one or more other pixels in the to-be-coded image area; for the pixels using the non-palette mode, determining coding information of the pixels using the non-palette mode according to whether pixel values of the pixels exist in prediction information and/or palette information of a coded image area; and performing bitstream coding on the coding information corresponding to the pixels using the non-palette mode. By means of the embodiments of the present invention, prediction information and palette information can be fully utilized to increase the compression ratio of pixels using a non-palette mode, and further, the coding bit cost is reduced.

Description

Image coding method, device and image processing device Technical field

The present invention relates to the field of graphic image technology, and in particular, to an image encoding method, apparatus, and image processing apparatus.

Background technique

Palette-based coding is widely used in graphic image technology (especially video coding technology). In the encoding process, for the image area to be encoded, for example, a coding unit (CU), including a plurality of pixels having color values (for example, RGB mode, having 24 bits of true color); in order to reduce the storage bits The storage capacity of the image image, which can usually point the pixel to the data index of the palette. During the decoding process, the color value of each output pixel can be determined by looking up a palette with a corresponding data index.

The palette is a set of pixel values. For pixels whose pixel values are in the palette, only the pixel index corresponding to the pixel value in the palette is used. Thereby, only the palette and the index corresponding to the pixels in the coding unit can be bit-stream encoded, and the bit cost of the coding can be reduced.

It should be noted that the above description of the technical background is only for the purpose of facilitating a clear and complete description of the technical solutions of the present invention, and is convenient for understanding by those skilled in the art. The above technical solutions are not considered to be well known to those skilled in the art simply because these aspects are set forth in the background section of the present invention.

Summary of the invention

Currently, in order to further increase the compression ratio, a scheme using a non-palette mode (for example, an escape mode) has appeared. Wherein for one or more pixels in the image region to be encoded (eg, CU), the pixel values of the pixel are directly encoded.

However, the inventors have found that for pixels adopting the non-palette mode, when the pixel value has a plurality of color components (for example, yCbCr), if the pixel value is directly used for encoding, more bits are required, and the encoded bits cannot be further reduced. cost.

Embodiments of the present invention provide an image encoding method, apparatus, and image processing apparatus. For non-toning The plate mode of the pixel further increases the compression ratio to reduce the bit cost of the encoding.

According to a first aspect of the embodiments of the present invention, an image encoding method is provided, including:

Determining a plurality of pixels in the encoded image region to determine a palette mode, and determining to adopt a non-palette mode for the other one or more pixels in the image region to be encoded;

For a pixel adopting the non-palette mode, determining whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region determines the encoding of the pixel in the non-palette mode. information;

The encoded information corresponding to the pixels in the non-palette mode is bit-stream encoded.

According to a second aspect of the embodiments of the present invention, an image encoding apparatus is provided, including:

a mode determining unit, determining, by using a palette mode, a plurality of pixels in the image region to be encoded, and determining to adopt a non-palette mode for the other one or more pixels in the image region to be encoded;

The encoding information determining unit determines, for the pixel adopting the non-palette mode, whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region, and determines the adopting the non-palette The encoded information of the pixels of the pattern;

The bit stream encoding unit performs bit stream encoding on the encoding information corresponding to the pixels in the non-palette mode.

According to a third aspect of the embodiments of the present invention, there is provided an image processing apparatus comprising the image encoding apparatus as described above.

According to still another aspect of an embodiment of the present invention, a computer readable program is provided, wherein when the program is executed in an image processing apparatus, the program causes a computer to perform image encoding as described above in the image processing apparatus method.

According to still another aspect of an embodiment of the present invention, a storage medium storing a computer readable program, wherein the computer readable program causes a computer to perform an image encoding method as described above in an image processing apparatus.

An advantageous effect of the embodiment of the present invention is that, for a pixel adopting the non-palette mode, determining whether the pixel value exists in the pre-generated prediction information and the palette information of the encoded image region, and determining the encoding according to the determination result. information. Thereby, the prediction information and the palette information can be fully utilized to improve the compression ratio of the pixels in the non-palette mode, further reducing the bit cost of encoding.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and drawings, indicating the The way that can be adopted. It should be understood that the embodiments of the invention are not limited in scope. The embodiments of the present invention include many variations, modifications, and equivalents within the scope of the appended claims.

Features described and/or illustrated with respect to one embodiment may be used in one or more other embodiments in the same or similar manner, in combination with, or in place of, features in other embodiments. .

It should be emphasized that the term "comprising" or "comprises" or "comprising" or "comprising" or "comprising" or "comprising" or "comprises"

DRAWINGS

Many aspects of the invention can be better understood with reference to the following drawings. The components in the figures are not drawn to scale, but only to illustrate the principles of the invention. In order to facilitate the illustration and description of some parts of the invention, the corresponding parts in the figures may be enlarged or reduced.

Elements and features described in one of the figures or one embodiment of the invention may be combined with elements and features illustrated in one or more other figures or embodiments. In the accompanying drawings, like reference numerals refer to the

1 is a schematic diagram of an example of a coding unit according to an embodiment of the present invention;

2 is a schematic diagram of another example of a coding unit according to an embodiment of the present invention;

3 is a schematic flow chart of an image encoding method according to an embodiment of the present invention;

4 is another schematic flowchart of an image encoding method according to an embodiment of the present invention;

FIG. 5 is another schematic flowchart of an image encoding method according to an embodiment of the present invention; FIG.

FIG. 6 is a schematic diagram of an image encoding apparatus according to an embodiment of the present invention; FIG.

Fig. 7 is a block diagram showing the configuration of an image processing apparatus according to an embodiment of the present invention.

detailed description

The foregoing and other features of the present invention will be apparent from the The specific embodiments of the present invention are disclosed in the specification and the drawings, which are illustrated in the embodiment of the invention The invention includes all modifications, variations and equivalents falling within the scope of the appended claims.

1 is a schematic diagram of an example of a coding unit according to an embodiment of the present invention, showing a coding unit (CU) Case. As shown in FIG. 1, the coding unit has 8 × 8 pixels; pixels having the same pixel value use the same symbol to represent pixel values, such as C0, C1, ..., C8.

If the current palette-based encoding method is employed, then C6, C7, and C8 in Figure 1 are all considered to be in a non-palette mode (which may also be referred to as an escape mode). The non-palette mode is adopted for C6, C7, and C8 in FIG. 1, and the other pixels are illustrated by using the palette mode as an example. At this time, the palette Palette={C0, C1, C2, C3, C4, C5} has 6 elements in the palette, so the pixel index can be represented by 3 bits.

FIG. 2 is a schematic diagram of another example of a coding unit according to an embodiment of the present invention, showing an index situation after the coding unit of FIG. 1 adopts a Palette. As shown in FIG. 2, the index of the pixel value C0 in the palette is 0, the index of the pixel value C1 in the palette is 1, the index of the pixel value C2 in the palette is 2, and the pixel value C3 is adjusted. The index in the swatch is 3, the index of the pixel value C4 in the palette is 4, and the index of the pixel value C5 in the palette is 5. There is no corresponding index value for C6, C7 and C8.

At this time, if each pixel has a plurality of color components (for example, y, Cb, Cr) and each color component value is represented by 8 bits, a scheme combining the current palette mode and the non-palette mode is adopted. At the time, for the pixels C6, C7, and C8 using the non-palette mode, the number of bits required for bit stream encoding is: 3*8*3=72 bits. Therefore, a larger number of bits is required, and the compression ratio cannot be further increased.

In view of the above technical problems, the embodiments of the present invention will be described in detail below.

Example 1

An embodiment of the present invention provides a method for encoding an image based on a palette, and FIG. 3 is a schematic flowchart of an image encoding method according to an embodiment of the present invention. As shown in FIG. 3, the encoding method includes:

Step 301: determining, by using a palette mode, a plurality of pixels in the image region to be encoded, and determining to adopt a non-pal palette mode for the other one or more pixels in the image region to be encoded;

Step 302: For pixels adopting the non-palette mode, determining whether pixels of the non-palette mode are used according to whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region. Coded information;

Step 303: Perform bitstream encoding on the coding information corresponding to the pixels in the non-palette mode.

In this embodiment, the image area to be encoded may be a current coding unit (CU) or a current maximum coding unit (LCU). The prediction information may be a pre-generated prediction table, where the prediction table includes a pixel index and a corresponding pixel value, wherein different pixel indexes correspond to different pixel values.

Table 1 shows a prediction table of an embodiment of the present invention. As shown in Table 1, the prediction table may have, for example, 8 prediction items, each prediction item being identified by one prediction index (for example, 0, 1, ..., 7; each prediction index may be represented by 3 bits), and Each prediction term represents a pixel value.

Table 1

Predictive index	0	1	2	3	4	......	......	7
									Pixel values	C9	C6	C0	C12	C8	......	......	C14

In this embodiment, each prediction term may include a plurality of color components. For example, the color component may include: a y component, a Cb component, and a Cr component; or the color component may include: an R component, a G component, or a B component. However, the invention is not limited thereto, and for example, other color components may also be used. The following is an example of yCbCr.

Table 2 is a practical example of the prediction table of the embodiment of the present invention, showing prediction information of an embodiment of the present invention. As shown in Table 2, the prediction table may have, for example, 64 prediction items, each prediction item being identified by one prediction index (for example, 0, 1, ..., 63; each may be represented by 6 bits), and each The prediction term represents a pixel value that includes a plurality of color components (eg, yCbCr).

Table 2

Predictive index	0	1	2	3	4	......	......	63
									y	118	120	122	112	218	......	......	220
Cb	50	50	78	117	118	......	......	130
									Cr	58	59	63	78	125	......	......	120

In the present embodiment, the prediction information may be generated in advance, for example, predefined on the encoding device side based on empirical values; and also predefined on the decoding device side. Thereby, both the encoding side and the decoding side can know the prediction information in advance, and it is not necessary to encode the prediction information by the bit stream.

Furthermore, the prediction information can also be updated based on the encoded pixel information. For example, after the encoding side determines that a pixel adopts the non-palette mode, the information of the pixel is added to the prediction table; and the same operation can be performed on the decoding side to generate the same prediction information as the encoding side, and the same does not need to pass. The bitstream encodes the prediction information.

In this embodiment, the encoded image area may be, for example, the previous CU of the current CU, the encoded image area. The palette information of the domain may include the palette of the previous CU. The palette is encoded by the bitstream, so when encoding or decoding the image region to be encoded (for example, the current CU), both the encoding side and the decoding side can know the coloring of the encoded image region (for example, the previous CU) in advance. Board information.

Table 3 shows palette information for an encoded image area of an embodiment of the present invention. As shown in Table 3, the palette information may have, for example, 8 pixel values, each pixel value being identified by a pixel index (eg, 0, 1, ..., 7; each pixel index may be represented by 3 bits) .

table 3

Pixel index	0	1	2	3	4	......	......	7
									Pixel values	C7	C13	C0	C12	C9	......	......	C14

In this embodiment, each pixel value may include a plurality of color components. For example, the color component may include: a y component, a Cb component, and a Cr component; or the color component may include: an R component, a G component, or a B component. However, the invention is not limited thereto, and for example, other color components may also be used. The following is an example of yCbCr.

Table 4 is a practical example of palette information of the encoded image area of the embodiment of the present invention. As shown in Table 4, the palette information may have, for example, 32 pixel values, each of which is identified by a pixel index (eg, 0, 1, ..., 31; each pixel index may be represented by 5 bits) Each pixel value includes a plurality of color components (eg, yCbCr).

Table 4

Pixel index	0	1	2	3	4	......	......	31
									y	90	120	120	125	218	......	......	222
Cb	50	50	80	90	119	......	......	133
									Cr	70	59	63	80	124	......	......	124

It should be noted that the foregoing only schematically shows the prediction information of the present invention and the palette information of the encoded image region, but the present invention is not limited thereto, and a specific implementation manner may be determined according to actual conditions. For example, the size of the prediction information and the specific content can be determined as needed.

In this embodiment, how to determine which pixels adopt the palette mode and which pixels adopt the non-palette mode in step 301 can refer to related technologies. For example, a pixel that appears only once in the CU can be determined as Use non-palette mode and more.

In this embodiment, the encoding information in step 302 may be a pixel value of the pixel (for example, including multiple color components); or may be a prediction index of the pixel value of the pixel in the prediction information, and the identifier is used in the prediction index. The flag bit; may also be a pixel index of the pixel value of the pixel in the palette information of the encoded image region, and an identification bit that identifies the palette information. The details will be described later.

FIG. 3 shows a case where only pixels in the non-palette mode are processed. 4 is another flow diagram of an image encoding method according to an embodiment of the present invention, showing a case where pixels in a non-palette mode and pixels in a palette mode are processed together.

As shown in FIG. 4, the encoding method includes:

Step 401: determining, by using a palette mode, a plurality of pixels in the image region to be encoded, and determining to adopt a non-palette mode for the other one or more pixels in the image region to be encoded.

Step 402: Determine a color palette corresponding to the palette mode, where the color palette includes a plurality of pixel values and a corresponding pixel index.

Step 403, for pixels adopting the palette mode, determining a corresponding pixel index based on the palette.

How to determine the palette mode or non-palette mode, how to determine the color palette and how to deal with the pixels in the palette mode, the specific content can refer to the related technology.

Step 404: For pixels adopting the non-palette mode, determining whether pixels of the non-palette mode are used according to whether the pixel values of the pixels exist in the pre-generated prediction information and the palette information of the encoded image region. Encoding information.

Specifically, for a pixel adopting a non-palette mode, in a case where the pixel value exists in the prediction information, a corresponding flag bit and a prediction index corresponding to a corresponding prediction item in the prediction information are used as The encoding information; in a case where the pixel value is not present in the prediction information and exists in palette information of the encoded image region, a corresponding identification bit and the encoded image region are a pixel index corresponding to a corresponding pixel value in the palette information as the encoding information; wherein the pixel value is not present in the prediction information and is not present in palette information of the encoded image region In the case, the corresponding flag bit and the pixel value are used as the encoding information.

Taking the CU of FIG. 1 and the prediction information of Table 1 as an example, if the current palette-based encoding method is adopted, as described above, bitstream encoding is performed for pixels C6, C7, and C8 using the non-palette mode. The number of bits required is: 3*8*3=72 bits.

If only prediction information is used for prediction, and C6 appears in the prediction information as shown in Table 1, it can be determined that the prediction index 1 corresponding to C6 (using 3 bits) and an identification bit (for example, 1 bit, indicating that the prediction information is used. The prediction index is used as the coding information of the C6. If C7 does not appear in the prediction information as shown in Table 1, it can be determined that the pixel value of C7 (using 3*8 bits) and one flag bit (for example, 0 bits indicating that the pixel value is directly used) are used as the coding information of the C7. . When C8 appears in the prediction information, it is determined that the prediction index 4 (using 3 bits) corresponding to C8 and one flag bit (for example, 1 bit indicating that the prediction index in the prediction information is used) are used as the coding information of the C8.

Thus, for pixels C6, C7, and C8 in the non-palette mode, the number of bits required for bitstream encoding is: C6 requires (3 + 1) = 4 bits, and C7 requires (3 * 8 + 1) = 25 Bit, C8 requires (3 + 1) = 4 bits. A total of 4+25+4=33 bits is required, which is 72-33=39 bits lower than the scheme of directly using pixel values.

With the coding method of the embodiment of the present invention, if C6 appears in the prediction information as shown in Table 1, it can be determined that the prediction index 1 (using 3 bits) corresponding to C6 and an identifier bit (for example, 1 bit, indicating prediction prediction) The prediction index in the information is used as the coding information of the C6. If C8 appears in the prediction information as shown in Table 1, it can be determined that the prediction index 4 corresponding to C8 (using 3 bits) and one flag bit (for example, 1 bit indicating that the prediction index in the prediction information is used) are used as the C8. Encoding information.

Further, C7 does not appear in the prediction information as shown in Table 1, but appears in the palette information of the encoded image area as shown in Table 3, and it is possible to determine the pixel index corresponding to C7 (using 3 bits). , an identification bit (for example, 0 bit, indicating that the prediction index in the prediction information is not used) and another flag bit (for example, 1 bit indicating the pixel index in the palette information of the encoded image region) as the coding of the C7 information.

Thus, for pixels C6, C7, and C8 in the non-palette mode, the number of bits required for bitstream encoding is: C6 requires (3 + 1) = 4 bits, and C7 requires (3 + 1 + 1) = 5 Bit, C8 requires (3 + 1) = 4 bits. A total of 4+5+4=13 bits is required. Therefore, 72-13=59 bits are reduced with respect to the scheme of directly using pixel values, and 33-13=20 bits are reduced with respect to the scheme using only prediction information. Thus, the embodiment of the present invention can further improve the compression ratio by using the prediction information and the palette information.

The embodiments of the present invention are further described below by way of examples of multiple color components.

In this embodiment, the pixel value and the prediction item may include a plurality of color components; for a pixel adopting the non-palette mode, it may first determine whether it exists in the prediction information, and if it does not exist in the prediction information, It is judged whether or not it exists in the palette information of the encoded image area. However, the present invention is not limited to the judgment order, and examples If it is also possible to first determine whether it exists in the palette information, and then determine whether it exists in the prediction information.

Hereinafter, it is determined by first determining whether or not it exists in the prediction information, and if it is not present in the palette information, it is described as an example.

In this embodiment, determining the encoding information of the pixels in the non-palette mode may include: respectively, each color component of the pixel is equal to a corresponding color component of a certain prediction item in the prediction information. Next, a 1-bit flag bit using the prediction information and a prediction index corresponding to the prediction item are used as the encoding information; each color component of the pixel is respectively color-coded with the encoded image region When the corresponding color components of the certain pixel values in the board information are equal, a 1-bit flag indicating that the prediction information is not used, a 1-bit flag indicating palette information using the encoded image region, and a pixel index corresponding to the pixel value as the encoding information; otherwise, a 1-bit flag indicating that the prediction information is not used, and a 1-bit flag indicating palette information not using the encoded image region And each color component of the pixel is used as the encoding information.

Taking yCbCr and the pixel in the non-palette mode as the pixel A, the prediction item in the prediction information is the prediction item B, and the pixel value in the palette information of the coded image area is C; for example, the embodiment of the present invention determines Whether the y component of the pixel A is equal to the y component of the prediction term B, whether the Cb component of the pixel A is equal to the Cb component of the prediction term B, and whether the Cr component of the pixel A is equal to the Cr component of the prediction term B; In the case where the results are all equal, it can be determined that the pixel value of the pixel A is equal to the prediction term B.

Alternatively, the embodiment of the present invention determines whether the y component of the pixel A and the y component of the pixel value C are equal, whether the Cb component of the pixel A is equal to the Cb component of the pixel value C, and the Cr component of the pixel A and the Cr component of the pixel value C. Whether they are equal; in the case where all three results are equal, it can be determined that the pixel value of the pixel A is equal to the pixel value C.

For example, the prediction information has 64 prediction items as shown in Table 2 above; the palette information of the encoded image area is as shown in Table 4 above, and has 32 pixel values. In the current CU, there are 16 pixels in the non-palette mode, as shown in Table 5 below.

table 5

	0	1	2	3	4	......	......	15
									y	119	120	122	115	218	......	......	222
Cb	50	50	78	160	119	......	......	133
									Cr	59	59	63	78	124	......	......	124

For the above pixels using the non-palette mode, if the current palette-based encoding method is employed, the number of bits required for bitstream encoding is: 16*(3*8)=384 bits.

If only prediction information is used for prediction, and each color component has two pixels equal to the corresponding color components in the prediction information as shown in Table 2 (the indexes in Table 5 are 1, 2, respectively), it can be determined that The two pixels may use the corresponding prediction indexes 1 and 2 in Table 2 (6 bits respectively) and the identification bits (for example, 1 bit, indicating the prediction index in the prediction information) as the coding information. Thus, the two pixels need to be: 2*(1+6)=14 bits.

The other 14 pixels directly use the pixel value and the identification bit (for example, 0 bit, indicating that the pixel value is directly used) as the encoding information, and thus, the 14 pixels need to be: 14*(1+3*8)=350 bits. A total of 14+350=364 bits is required, which is 384-364=20 bits lower than the scheme of directly using pixel values.

However, if the encoding method of the embodiment of the present invention has two pixels each having the same color component as the corresponding color component in the prediction information shown in Table 2 (the indexes in Table 5 are 1, 2, respectively), It can be determined that the two pixels can adopt the corresponding prediction indexes 1 and 2 in Table 2 (using 6 bits respectively) and the identification bits (for example, 1 bit, indicating that the prediction index in the prediction information is used) as the coding information. Thus, the two pixels need to be: 2*(1+6)=14 bits.

Further, each of the color components has two pixels equal to the corresponding color components in the palette information of the encoded image region as shown in Table 4 (the indexes in Table 5 are 4, 15 respectively), and then it can be determined The two pixels may adopt the corresponding prediction indexes 4, 31 in Table 4 (using 5 bits respectively), 1-bit flag bits (for example, 0 bits, indicating that the prediction index in the prediction information is not used) and 1-bit flag bits (for example, 1) The bit, which indicates the pixel index of the encoded image region, is used as the encoded information. Thus, the two pixels need to be: 2*(1+1+5)=14 bits.

The other 12 pixels directly adopt the pixel value, the 1-bit flag (for example, 0 bit, indicating that the prediction index in the prediction information is not used) and the 1-bit flag (for example, 0 bit, indicating that the pixel index of the encoded image region is not used) As the coding information, thus, these 12 pixels need to be: 12*(1+1+3*8)=312 bits.

Therefore, the encoding method using the embodiment of the present invention requires a total of 14+14+312=340 bits, which is 384-340=44 bits lower than the scheme of directly using the pixel value, and is reduced by 364- relative to the scheme using only prediction information. 340 = 24 bits. Thus, the embodiment of the present invention can further improve by using prediction information and palette information. Compression ratio.

Step 405: Perform bitstream encoding on the encoding information corresponding to the pixels in the non-palette mode, and perform bitstream encoding on the pixel index corresponding to the pixels in the palette mode.

It should be noted that the above is only a schematic description of the identification bits, but the invention is not limited thereto. For example, it is also possible to use 00 to represent the prediction index in the prediction information, 01 to use the pixel index in the palette information, 1 to directly use the pixel value, and the like.

In this embodiment, the palette information of the current CU and the like may be incorporated into the bit stream, and the related art may be specifically referred to. In addition, FIG. 4 is only schematically illustrated, but the present invention is not limited thereto, and for example, the execution order of each step may be changed according to actual conditions.

In the present embodiment, for each pixel in one coding unit, information that is encoded separately can be determined at the time of scanning. FIG. 5 is another schematic flowchart of an image encoding method according to an embodiment of the present invention. As shown in FIG. 5, the image encoding method includes:

Step 500, determining a mode of each pixel in the CU and a palette of the CU;

Step 501, it is determined whether the current pixel adopts the non-palette mode; in the case of adopting the palette mode, step 507 is performed, and in the case of adopting the non-palette mode, step 502 is performed;

Step 502, it is determined whether the color component of the current pixel is equal to the corresponding color component in a certain prediction item, if yes, step 503 is performed, otherwise step 504 is performed;

Step 503: The corresponding identifier bit and the prediction index corresponding to the prediction item are used as coding information.

Step 504, it is determined whether the color component of the current pixel is equal to the corresponding color component of a certain pixel value in the palette information of the encoded image region, if yes, step 505 is performed, otherwise step 506 is performed;

Step 505: The corresponding identifier bit and the pixel index corresponding to the pixel value are used as encoding information.

Step 506, using corresponding identifier bits and each color component value as encoding information;

Step 507, determining a corresponding pixel index based on the color palette;

In step 508, it is determined whether there are other pixels, and if so, step 501 is performed for the next pixel.

For the sake of simplicity, only the content of the information for determining the encoding of each pixel is shown in FIG. 5, and other contents such as bit stream encoding are not shown. After determining the information for encoding each pixel, the bit stream encoding may be performed immediately, or all pixels may be bit stream encoded after the scanning is completed, and the encoding time may be determined according to actual conditions.

It can be seen from the above embodiment that for pixels adopting the non-palette mode, it is determined whether the pixel value exists in advance. In the generated prediction information and the palette information of the encoded image region, the information to be encoded is determined based on the determination result. Thereby, the prediction information and the palette information can be fully utilized to improve the compression ratio of the pixels in the non-palette mode, and the bit cost of encoding can be further reduced.

Example 2

An embodiment of the present invention provides an image encoding apparatus, which corresponds to the image encoding method in Embodiment 1, and the same content is not described herein again.

FIG. 6 is a schematic diagram of an image encoding apparatus according to an embodiment of the present invention. As shown in FIG. 6, the encoding apparatus 600 includes: a mode determining unit 601, an encoding information determining unit 602, and a bit stream encoding unit 603;

Wherein, the mode determining unit 601 determines to adopt a palette mode for a plurality of pixels in the image region to be encoded, and determines to adopt a non-pal palette mode for the other one or more pixels in the image region to be encoded; the encoding information determining unit 602. For a pixel adopting the non-palette mode, determining whether the pixel value of the pixel is in the non-palette mode pixel according to whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region. Encoding information; the bit stream encoding unit 603 performs bit stream encoding on the encoding information corresponding to the pixels in the non-palette mode.

As shown in FIG. 6, the apparatus 600 may further include: a palette determining unit 604 and an index information determining unit 605. The palette determining unit 604 determines a palette corresponding to the palette mode, the palette includes a plurality of pixel values and corresponding pixel indexes; and the index information determining unit 605 is configured to adopt a palette mode. And determining, by the pixel, a corresponding pixel index; and the bitstream encoding unit 603 is further configured to: perform bitstream encoding on the pixel index corresponding to the pixel in the palette mode.

In this embodiment, the prediction information may include a plurality of prediction items and corresponding prediction indexes, wherein different prediction indexes correspond to different prediction items; the palette information of the encoded image regions includes a plurality of pixel values and corresponding pixel indexes. Where different pixel indices correspond to different pixel values.

The encoding information determining unit 602 may be configured to: when the pixel value exists in the prediction information, use a corresponding identifier bit and a prediction index corresponding to a corresponding prediction item in the prediction information as the Encoding information; in the case where the pixel value does not exist in the prediction information and exists in palette information of the encoded image region, the corresponding flag bit and the color of the encoded image region a pixel index corresponding to a corresponding pixel value in the board information as the encoding information; in a case where the pixel value does not exist in the prediction information and is not present in palette information of the encoded image area , the corresponding flag and The pixel value is used as the encoded information.

Further, each prediction term may include a plurality of color components, and each pixel value may include a plurality of color components. The encoding information determining unit 602 may be specifically configured to: when each color component of the pixel is equal to a corresponding color component in a certain prediction item in the prediction information, respectively, to represent 1 bit using the prediction information And a prediction index corresponding to the prediction item as the encoding information; each color component of the pixel and a corresponding color component of a certain pixel value in the palette information of the encoded image region In the case of equality, a 1-bit flag indicating that the prediction information is not used, a 1-bit flag indicating palette information using the encoded image region, and a pixel index corresponding to the pixel value are used as the Encoding information; otherwise, a 1-bit flag indicating that the prediction information is not used, a 1-bit flag indicating that the palette information of the encoded image region is not used, and each color component of the pixel are used as the encoding information.

In the present embodiment, the color component may include: a y component, a Cb component, and a Cr component; or the color component may include: an R component, a G component, or a B component. However, the invention is not limited thereto, and for example, other color components may also be used.

In this embodiment, as shown in FIG. 6, the apparatus 600 may further include: a prediction information generating unit 606, generating the prediction information, and updating the prediction information based on the encoded pixel information.

In this embodiment, the image area to be encoded may be the current CU, and the encoded image area may be the previous CU of the current CU. However, the invention is not limited thereto.

As is apparent from the above embodiment, it is determined whether or not the pixel value exists in the pre-generated prediction information and the palette information of the encoded image region in the pixel in the non-palette mode, and the information to be encoded is determined based on the determination result. Thereby, the prediction information and the palette information can be fully utilized to improve the compression ratio of the pixels in the non-palette mode, further reducing the bit cost of encoding.

Example 3

An embodiment of the present invention provides an image processing apparatus, where the image processing apparatus includes the image encoding apparatus according to Embodiment 2.

Fig. 7 is a block diagram showing the configuration of an image processing apparatus according to an embodiment of the present invention. As shown in FIG. 7, the image processing apparatus 700 may include a central processing unit (CPU) 100 and a memory 110; the memory 110 is coupled to the central processing unit 100. Wherein the memory 110 can store various data; in addition, a program for information processing is stored, and This program is executed under the control of the central processing unit 100.

In one embodiment, the functionality of image encoding device 600 may be integrated into central processor 100. Wherein, the central processing unit 100 can be configured to implement the image encoding method as described in Embodiment 1.

In another embodiment, the image encoding device 600 may be configured separately from the central processing unit. For example, the image encoding device 600 may be configured as a chip connected to the central processing unit 100, and the image encoding device 600 may be implemented by control of the central processing unit. Features.

In addition, as shown in FIG. 7, the image processing apparatus 700 may further include: an input and output unit 120, a display unit 130, and the like; wherein the functions of the above components are similar to those of the prior art, and are not described herein again. It is to be noted that the image processing apparatus 700 does not necessarily have to include all of the components shown in FIG. 7; in addition, the image processing apparatus 700 may further include components not shown in FIG. 7, and reference may be made to the related art.

In the present embodiment, the image processing apparatus 700 may further include: an image decoding device that can perform decoding correspondingly. The image processing apparatus 700 can implement the functions of the image decoding apparatus by the control of the central processing unit 100 as described above.

The embodiment of the present invention further provides a computer readable program, wherein when the program is executed in an image processing apparatus, the program causes a computer to execute the image encoding method described in Embodiment 1 in the image processing apparatus.

An embodiment of the present invention further provides a storage medium storing a computer readable program, wherein the computer readable program causes a computer to execute the image encoding method described in Embodiment 1 in an image processing apparatus.

The above apparatus and method of the present invention may be implemented by hardware or by hardware in combination with software. The present invention relates to a computer readable program that, when executed by a logic component, enables the logic component to implement the apparatus or components described above, or to cause the logic component to implement the various methods described above Or steps. The present invention also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, or the like.

One or more of the functional blocks described in the figures and/or one or more combinations of functional blocks may be implemented as a general purpose processor, digital signal processor (DSP) for performing the functions described herein. An application specific integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof. One or more of the functional blocks described with respect to the figures and/or one or more combinations of functional blocks may also be implemented as a combination of computing devices, eg, a combination of a DSP and a microprocessor, multiple microprocessors One or more microprocessors in conjunction with DSP communication or any other such configuration.

The present invention has been described in connection with the specific embodiments thereof, and it should be understood by those skilled in the art that A person skilled in the art can make various modifications and changes to the present invention within the scope of the present invention.

Claims (20)

1. An image encoding method, the image encoding method comprising:

   Determining a plurality of pixels in the encoded image region to determine a palette mode, and determining to adopt a non-palette mode for the other one or more pixels in the image region to be encoded;

   For a pixel adopting the non-palette mode, determining whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region determines the encoding of the pixel in the non-palette mode. information;

   The encoded information corresponding to the pixels in the non-palette mode is bit-stream encoded.
2. The image encoding method according to claim 1, wherein the method further comprises:

   Determining a palette corresponding to the palette mode, the palette comprising a plurality of pixel values and a corresponding pixel index;

   For pixels in the palette mode, a corresponding pixel index is determined based on the palette, and

   The pixel index corresponding to the pixel in the palette mode is bit stream encoded.
3. The image encoding method according to claim 1, wherein the prediction information includes a plurality of prediction items and a corresponding prediction index, wherein different prediction indexes correspond to different prediction items;

   The palette information of the encoded image region includes a plurality of pixel values and corresponding pixel indices, wherein different pixel indices correspond to different pixel values.
4. The image encoding method according to claim 3, wherein the determining the encoding information of the pixels in the non-palette mode comprises:

   In a case where the pixel value exists in the prediction information, a corresponding index bit and a prediction index corresponding to a corresponding prediction item in the prediction information are used as the encoding information;

   In the case where the pixel value is not present in the prediction information and exists in the palette information of the encoded image region, the corresponding identification bit and the palette information of the encoded image region are a pixel index corresponding to the corresponding pixel value as the encoded information;

   In the case where the pixel value does not exist in the prediction information and does not exist in the palette information of the encoded image region, the corresponding flag bit and the pixel value are used as the encoding information.
5. The image encoding method according to claim 3, wherein each of said prediction items includes a plurality of color components, each of said pixel values including a plurality of color components.
6. The image encoding method according to claim 5, wherein the determining the encoding information of the pixels in the non-palette mode comprises:

   In a case where each color component of the pixel is respectively equal to a corresponding color component of a certain prediction item in the prediction information, a 1-bit flag indicating use of the prediction information and a corresponding one of the prediction items are indicated Predicting an index as the encoded information;

   In the case where each color component of the pixel is respectively equal to a corresponding color component of a certain pixel value in the palette information of the encoded image region, a 1-bit flag indicating that the prediction information is not used will be indicated a 1-bit flag indicating the palette information of the encoded image region and a pixel index corresponding to the pixel value as the encoding information;

   Otherwise, a 1-bit flag indicating that the prediction information is not used, a 1-bit flag indicating that the palette information of the encoded image region is not used, and each color component of the pixel are used as the encoding information.
7. The image encoding method according to claim 6, wherein the color component comprises: a y component, a Cb component, and a Cr component;

   Or include: R component, G component, or B component.
8. The image encoding method according to claim 1, wherein the prediction information is generated in advance and updated based on the encoded pixel information.
9. The image encoding method according to claim 1, wherein the image area to be encoded is a current encoding unit, and the encoded image area is a previous encoding unit of the current encoding unit.
10. An image encoding device, the image encoding device comprising:

    a mode determining unit, determining, by using a palette mode, a plurality of pixels in the image region to be encoded, and determining to adopt a non-palette mode for the other one or more pixels in the image region to be encoded;

    The encoding information determining unit determines, for the pixel adopting the non-palette mode, whether the pixel value of the pixel exists in the pre-generated prediction information and the palette information of the encoded image region, and determines the adopting the non-palette The encoded information of the pixels of the pattern;

    The bit stream encoding unit performs bit stream encoding on the encoding information corresponding to the pixels in the non-palette mode.
11. The image encoding device according to claim 10, wherein the device further comprises:

    a palette determining unit, determining a palette corresponding to the palette mode, the palette comprising a plurality of pixel values and a corresponding pixel index;

    An index information determining unit, for a pixel adopting a palette mode, determining a corresponding pixel index based on the palette, and

    The bitstream encoding unit is further configured to perform bitstream encoding on the pixel index corresponding to the pixel in the palette mode.
12. The image encoding apparatus according to claim 10, wherein the prediction information includes a plurality of prediction items and a corresponding prediction index, wherein different prediction indexes correspond to different prediction items;

    The palette information of the encoded image region includes a plurality of pixel values and corresponding pixel indices, wherein different pixel indices correspond to different pixel values.
13. The image encoding device according to claim 12, wherein said encoding information determining unit is configured to:

    In a case where the pixel value exists in the prediction information, a corresponding index bit and a prediction index corresponding to a corresponding prediction item in the prediction information are used as the encoding information;

    In the case where the pixel value is not present in the prediction information and exists in the palette information of the encoded image region, the corresponding identification bit and the palette information of the encoded image region are a pixel index corresponding to the corresponding pixel value as the encoded information;

    In the case where the pixel value does not exist in the prediction information and does not exist in the palette information of the encoded image region, the corresponding flag bit and the pixel value are used as the encoding information.
14. The image encoding device according to claim 12, wherein each of said prediction items includes a plurality of color components, each of said pixel values including a plurality of color components.
15. The image encoding device according to claim 14, wherein the encoding information determining unit is configured to:

    In a case where each color component of the pixel is respectively equal to a corresponding color component in a certain prediction item in the prediction information, a 1-bit flag indicating the use of the prediction information and a corresponding one of the prediction items are indicated Predicting an index as the encoded information;

    In a case where each color component of the pixel is respectively equal to a corresponding color component of a certain pixel value in the palette information of the encoded image region, a 1-bit flag indicating that the prediction information is not used will be indicated a 1-bit flag indicating the palette information of the encoded image region and a pixel index corresponding to the pixel value as the encoding information;

    Otherwise, a 1-bit flag indicating that the prediction information is not used, a 1-bit flag indicating that the palette information of the encoded image region is not used, and each color component of the pixel are used as the encoding information.
16. The image encoding device according to claim 15, wherein said color component comprises: a y component, Cb component and Cr component;

    Or include: R component, G component, or B component.
17. The image encoding device according to claim 10, wherein the device further comprises:

    The prediction information generating unit generates the prediction information, and updates the prediction information based on the encoded pixel information.
18. The image encoding apparatus according to claim 10, wherein the image area to be encoded is a current encoding unit, and the encoded image area is a previous encoding unit of the current encoding unit.
19. An image processing apparatus comprising: the image encoding apparatus according to any one of claims 10 to 18.
20. The image processing device according to claim 19, wherein the image processing device further comprises:

    A decoding device that decodes the bitstream to obtain an image.

Images