WO2018170801A1 - 图像滤波方法及装置 - Google Patents

图像滤波方法及装置 Download PDF

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Publication number
WO2018170801A1
WO2018170801A1 PCT/CN2017/077750 CN2017077750W WO2018170801A1 WO 2018170801 A1 WO2018170801 A1 WO 2018170801A1 CN 2017077750 W CN2017077750 W CN 2017077750W WO 2018170801 A1 WO2018170801 A1 WO 2018170801A1
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Prior art keywords
filter
coefficients
luma
type
chroma
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PCT/CN2017/077750
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English (en)
French (fr)
Inventor
安基程
郑建铧
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华为技术有限公司
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Priority to PCT/CN2017/077750 priority Critical patent/WO2018170801A1/zh
Priority to EP17901591.2A priority patent/EP3595317A4/en
Priority to CN201780088778.4A priority patent/CN110463206B/zh
Priority to PCT/CN2017/115683 priority patent/WO2018171265A1/zh
Publication of WO2018170801A1 publication Critical patent/WO2018170801A1/zh
Priority to US16/577,507 priority patent/US11190778B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/117—Filters, e.g. for pre-processing or post-processing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/20—Image enhancement or restoration by the use of local operators
    • G06T5/92—
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/186—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/46—Embedding additional information in the video signal during the compression process
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/63—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding using sub-band based transform, e.g. wavelets
    • H04N19/64—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding using sub-band based transform, e.g. wavelets characterised by ordering of coefficients or of bits for transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/80—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation
    • H04N19/82—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation involving filtering within a prediction loop

Definitions

  • the present application relates to the field of video image coding and decoding technologies, and more particularly, to an image filtering method and apparatus.
  • Digital video devices are now widely used, such as digital television, digital live broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, digital cameras, digital recording devices, digital media playback. , video game devices, video game consoles, cellular or satellite radio phones, video conferencing devices, and the like.
  • Digital video devices typically compress video using video compression techniques based on a block-based hybrid video coding framework, such as MPEG-1/2 to the latest video coding standard H.265/HEVC, for more efficient transmission, reception, and storage. Digital video information.
  • Adaptive loop filter is one of the important techniques of video coding and decoding.
  • ALF can improve the quality of reconstructed image and reduce image distortion by filtering the reconstructed image obtained by codec.
  • the existing adaptive loop filtering separately processes the luminance pixel and the chrominance pixel when filtering the image, and separately transmits the respective filter coefficients to the luminance pixel and the chrominance pixel, which causes the code to be transmitted.
  • the rate has increased.
  • the present application provides an image wave method and apparatus capable of reducing transmission of a code rate.
  • an image filtering method comprising: determining a filter coefficient of a chroma filter according to a filter coefficient of a luminance filter, wherein the luminance filter and the chroma filter are respectively used Performing filtering processing on the luma pixel and the chroma pixel of the image to be processed, all filter coefficients of the luma filter exhibiting a first geometrical distribution, and all filter coefficients of the chroma filter exhibit a second geometrical distribution, The first geometric distribution and the second geometric distribution are similar patterns, and the filter coefficients of the chroma filter at the edge of the second geometric distribution are comprised by one or more luminance filters at the edge of the first geometric distribution Filter coefficients are calculated; the filtering process is performed on the luma pixels and the chroma pixels, respectively, by using the luma filter and the chroma filter.
  • the filter coefficient of the chroma filter can be determined according to the filter coefficient of the luma filter, so that only the code stream corresponding to the filter coefficient of the luma filter needs to be transmitted when the code stream is transmitted, and the transmitted code stream can be saved.
  • the determining, by the filter coefficients of the luminance filter, the filter coefficients of the chroma filter including: according to the first class in the luminance filter Filter coefficients, determining a third type of filter coefficients in the chroma filter; determining a fourth type of filter coefficients in the chroma filter according to a second type of filter coefficients in the luma filter
  • the fourth type of filter coefficients are filter coefficients of the chroma filter at the edge of the second geometric distribution
  • the third filter coefficients are the chroma filter a filter coefficient other than a fourth type of filter coefficient
  • the first type of filter coefficient being a position relative to a geometric center of the first geometrical distribution and one of the third type of filter coefficients being relative to the first
  • the geometrical centers of the two geometrical distributions have the same filter coefficients
  • the second type of filter coefficients are filter coefficients of the luminance filter other than the first type of filter coefficients.
  • the determining, according to the first type of filter coefficients in the luminance filter, determining a third type of filter coefficients in the chroma filter coefficients includes: assigning a value of a first luma filter coefficient of the first type of filter coefficients to a first chroma filter coefficient of the third type of filter coefficients, wherein the first chroma filter The position of the coefficient relative to the geometric center of the second geometric distribution is the same as the position of the first luma filter coefficient relative to the geometric center of the first geometrical distribution.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter being a filter having a 5 ⁇ 5 diamond tap.
  • the first geometric distribution is a 9 ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the first type of filter coefficients include L20, L12, L19
  • the third type of filter coefficients include C6.
  • C2, C5 wherein the filter coefficients of the luminance filter are L0, L1, L2, L3, L4, L5, L6, L7, L8, L9 in the raster scan order in the 9 ⁇ 9 diamond distribution.
  • the filter coefficients of the chrominance filter are sequentially C0, C1, C2, C3, C4, C5 in the raster scan order in the 5 ⁇ 5 diamond distribution.
  • a first chrominance filter coefficients comprising: L20, L12 and L19 are as C6, C2 and C5.
  • the luminance filter is a filter having a 7 ⁇ 7 diamond tap
  • the chroma filter being a filter having a 5 ⁇ 5 diamond tap.
  • the first geometric distribution is a 7 ⁇ 7 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the first type of filter coefficients include M12, M6, M11
  • the third type of filter coefficients include C6.
  • C2, C5 wherein the filter coefficients of the luminance filter are sequentially M0, M1, M2, M3, M4, M5, M6, M7, M8, M9 in the raster scan order in the 9 ⁇ 9 diamond distribution.
  • the filter coefficients of the chroma filter are in the 5 ⁇ 5 diamond distribution According to the raster scanning order, C0, C1, C2, C3, C4, C5, C6, C5, C4, C3, C2, C1, C0, the first brightness filter of the first type of filter coefficients is described.
  • the value of the coefficient is assigned to the first chrominance filter coefficient of the third type of filter coefficients, including: M12, M6, and M11 as C6, C2, and C5, respectively.
  • determining the fourth type of filter coefficients of the chroma filter according to the second type of filter coefficients of the luma filter including: The value of the second luma filter coefficient of the second type of filter coefficients is added to the value of the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient as the fourth category a value of a second chrominance filter coefficient of the filter coefficient, wherein a position of the second chrominance filter coefficient relative to a geometric center in the second geometric distribution and the second luminance filter coefficient are The position in the first geometrical distribution is the same relative to the geometric center.
  • the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient comprises: filtering with the second luma The second coefficient of the second type of filter coefficients adjacent or at intervals K in the first geometric distribution, wherein K is an integer greater than or equal to one.
  • the second brightness filter coefficient At least one third luma filter coefficient having a neighborhood relationship, comprising: adjacent to or spaced apart from said second luma filter coefficient in said first geometrical distribution, and geometric center relative to said first geometrical distribution
  • the second type of filter coefficients having a distance greater than a distance of the second luma filter coefficient relative to a geometric center of the first geometrical distribution, wherein K is an integer greater than or equal to one.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter being a filter having a 5 ⁇ 5 diamond tap.
  • the first geometric distribution is a 9 ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the second type of filter coefficients include L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L13, L14, L15, L16, L17 and L18
  • the fourth type of filter coefficients include C0, C1, C3 and C4, wherein the filter coefficients of the luminance filter are in
  • the 9 ⁇ 9 diamond distribution is sequentially L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16, L17, L18 according to the raster scanning order.
  • the chromaticity filter The filter coefficients of the filter are sequentially C0, C1, C2, C3, C4, C5, C6, C5, C4, C3, C2, C1, C0 in the 5 ⁇ 5 diamond distribution according to the raster scanning order.
  • the value of the second chrominance filter coefficient includes: a sum of L1, L2, L3, L0, and L6 as C0; a sum of L4, L5, L10, and L11 as C1; a sum of L7, L8, L13, and L14 As C3; the sum of L9, L15, L16, L17, and L18 is taken as C4.
  • the luminance filter is a filter having a 7 ⁇ 7 diamond tap
  • the chroma filter being a filter having a 5 ⁇ 5 diamond tap.
  • the first geometric distribution is a 7 ⁇ 7 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the second type of filter coefficients include M0, M1, M2, M3, M4, M5, M7, M8, M9 and M10
  • the fourth type of filter coefficients include C0, C1, C3, and C4, wherein the filter coefficients of the luminance filter are sequentially M0, M1 in the raster scan order in the 9 ⁇ 9 diamond distribution.
  • the filter coefficients of the degree filter are sequentially C0, C1, C2, C3, C4, C5, C6, C5, C4, C3, C2, C1, C0 in the 5 ⁇ 5 diamond distribution according to the raster scanning order.
  • a value of the second luma filter coefficient of the second type of filter coefficients and at least one third luma filter having a neighborhood relationship with the second luma filter coefficient The values of the numbers are added as the value of the second chrominance filter coefficient in the fourth type of filter coefficients, including: taking the sum of M0 and M2 as C0; and summing M1, M4, and M5 as C1; The sum of M3, M8 and M7 is taken as C3; the sum of M9 and M10 is taken as C4.
  • the method further comprises determining that the number of taps of the luminance filter is greater than or equal to a preset value.
  • the determining, by the filter coefficients of the luma filter, the filter coefficients of the chroma filter comprises: determining a number of taps of the luma filter; In the case where the number of taps of the luminance filter is less than a preset value, the filter coefficient of the luminance filter is used as the chrominance filter coefficient of the chrominance filter.
  • the filter coefficient of the luminance filter can be directly used as the filter coefficient of the chroma filter (in this case, the same filter is used for filtering the luminance pixel and the chroma pixel) , The process of determining the filter coefficients of the chroma filter is simplified.
  • the using the filter coefficients of the luma filter as the chroma filter coefficients of the chroma filter comprises: selecting a fourth of the luma filters a luminance filter coefficient as a fourth chrominance filter coefficient in the chrominance filter, wherein a position of the fourth chrominance filter coefficient relative to a geometric center in the second geometric distribution and the first The four luma filter coefficients are the same in position relative to the geometric center in the first geometrical distribution.
  • the method before determining the filter coefficients of the chroma filter according to the filter coefficients of the luma filter, the method further includes: classifying the luma pixels, Obtaining a plurality of luma pixels; classifying the chroma pixels to obtain a plurality of chroma pixels, wherein the classification of any one of the plurality of chroma pixels and the brightness of the same sampling position The class of the pixel class is the same; the brightness filtering identification information of the brightness pixel is determined, wherein the brightness filtering identification information is used to indicate that the filtering process is performed on the brightness pixel and the chrominance pixel of the corresponding sampling position. .
  • the method is applied to a decoder, the method further comprising, prior to determining a filter coefficient of the chroma filter based on filter coefficients of the luma filter : Parsing the code stream to obtain filter coefficients of the luminance filter.
  • the method is applied to an encoder, the method further comprising: encoding filter coefficients of the luminance filter.
  • the encoder only needs to encode the filter coefficients of the luminance filter during encoding, and does not need to encode the filter coefficients of the chroma filter, which saves the code stream that needs to be transmitted.
  • an image filtering apparatus comprising means for performing the method of the first aspect or various implementations thereof.
  • an image filtering apparatus comprising: a non-volatile storage medium, and a central processing unit, the non-volatile storage medium storing an executable program, the central processor and the non- Volatile storage media are coupled and the executable program is executed to implement the methods of the first aspect or various implementations thereof.
  • a computer readable medium storing program code for device execution, the program code comprising instructions for performing the method of the first aspect or various implementations thereof.
  • Figure 1 is a schematic diagram of a 4:4:4 sampling format.
  • Figure 2 is a schematic diagram of a 4:2:2 sampling format.
  • Figure 3 is a schematic diagram of a 4:1:1 sampling format.
  • Figure 4 is a schematic illustration of the 4:2:0 sampling format.
  • FIG. 5 is a schematic flowchart of an image filtering method according to an embodiment of the present application.
  • Figure 6 is a schematic illustration of a 9 x 9 diamond tap filter.
  • Figure 7 is a schematic illustration of a 7 x 7 diamond tap filter.
  • Figure 8 is a schematic illustration of a 7 x 7 diamond tap filter.
  • Figure 9 is a schematic illustration of a 5 x 5 diamond tap filter.
  • Figure 10 is a schematic illustration of a 5 x 5 diamond tap filter.
  • FIG. 11 is a schematic diagram showing classification results obtained by classifying luminance pixels and chrominance pixels of a certain image.
  • FIG. 12 is a schematic block diagram of an image filtering apparatus according to an embodiment of the present application.
  • FIG. 13 is a schematic block diagram of an image filtering apparatus according to an embodiment of the present application.
  • FIG. 14 is a schematic block diagram of a codec apparatus according to an embodiment of the present application.
  • FIG. 15 is a schematic diagram of a codec apparatus according to an embodiment of the present application.
  • FIG. 16 is a schematic block diagram of a video codec system according to an embodiment of the present application.
  • the YCbCr model, the luminance pixel, and the chrominance pixel according to the embodiment of the present application are first introduced.
  • the YCbCr model is a different color model from the RGB model.
  • the RGB model is a combination of luminance and chrominance
  • the YCbCr model is a representation of luminance and chrominance.
  • the YCbCr model includes three components (Y, Cb, Cr), where Y is the luminance component, Cb is the first chrominance component, and Cr is the second chrominance component (of course, Cr can also be referred to as the first chrominance component.
  • Cb is referred to as a second chrominance component
  • the first chrominance component and the second chrominance component may be collectively referred to as a chrominance component.
  • pixels (points) in an image include luminance pixels (dots), first chrominance pixels (points), and second chrominance pixels (points), wherein the first chrominance pixels and
  • the second chrominance pixels may be collectively referred to as chrominance pixels.
  • each small rectangle represents one pixel, and different circles respectively indicate luminance sampling, first chrominance sampling, and second chrominance sampling.
  • luminance sampling and chrominance sampling are performed for each pixel. That is to say, 4 times of luminance sampling, 4 times of first chrominance sampling and 4 times of second chrominance sampling are performed in every 4 pixels, and the adopted format is called 4:4:4.
  • the chroma sampling ratio can be smaller than the luminance sampling ratio when sampling the pixels of the image ( As shown in FIGS. 2 to 4, luminance sampling is performed for each pixel, and for chroma sampling, chroma sampling may be performed once every 2 or every 4 pixels).
  • luminance is sampled for each pixel, and chrominance sampling is performed once every 2 pixels in the horizontal direction. That is to say, 4 times of luminance sampling, 2 times of first chrominance sampling and 2 times of second chrominance sampling are performed in every 4 pixels, and this sampling format is called 4:2:2.
  • the sampling ratio is half of the luminance sampling ratio.
  • luminance is sampled for each pixel, and chroma sampling is performed once every 4 pixels in the horizontal direction. That is to say, 4 times of luminance sampling is performed every 4 pixels, 1 time of first chrominance sampling, and 1st time Two-color sampling, this format is called 4:1:1.
  • the sampling ratio is one quarter of the luminance pixel sampling ratio.
  • each pixel is subjected to luminance sampling.
  • the first chrominance sampling is performed once every 2 pixels, and in the pixels of the second row, every 2 pixels are performed.
  • a second chroma sampling this format is called 4:2:0.
  • the samples of the first chrominance and the second chrominance are separated, and in FIGS. 1 to 3, the first chrominance and the second chrominance are sampled together, that is, In FIG. 1 to FIG. 3, for a certain pixel, if chrominance sampling is performed, first chrominance sampling and second chrominance sampling are performed, and in FIG. 4, for a certain pixel, If chroma sampling is performed, then either the first chroma sampling or the second chroma sampling may be selected.
  • the sampling type of the pixel of the image to be processed may be any one of FIG. 1 to FIG. 4.
  • the existing adaptive loop filtering separates the luminance pixel and the chrominance pixel when filtering the pixels of the image, and for the luminance pixel, according to the relationship between the current luminance pixel and the surrounding adjacent luminance pixel, the luminance is
  • the pixels are divided into N categories, and the same type of luminance filter is used for the same type of luminance pixels (that is, the same set of filter coefficients are used), and the same adaptive filter can be used for different types of luminance pixels, or different Adaptive filter.
  • the existing method does not use the relationship between the current chroma pixels and the surrounding adjacent chroma pixels, but instead uses an adaptive filter (that is, another set of filters is used).
  • the coefficient of the chrominance pixel of the entire picture is filtered.
  • the filter coefficients of the chrominance pixel and the luminance pixel are both transmitted, which leads to an increase in the transmission rate.
  • the embodiment of the present application proposes an adaptive loop filtering method, which can determine a filter coefficient of a chroma pixel according to a filter coefficient of a luma pixel, so that only the filter coefficient of the luma pixel needs to be transmitted, and the color
  • the filter coefficients of the degree pixels can be determined according to the filter coefficients of the luminance pixels, which can save the transmission rate.
  • FIG. 5 is a schematic flowchart of an adaptive loop filtering method according to an embodiment of the present application.
  • the method of Figure 5 includes:
  • the brightness filter is used for filtering processing on luminance pixels of an image to be processed.
  • All filter coefficients of the luminance filter exhibit a first geometric distribution
  • all filter coefficients of the chroma filter exhibit a second geometric distribution
  • the first geometric distribution and the second geometric distribution are similar graphics
  • the filter coefficients of the degree filter are calculated by one or more filter coefficients of the brightness filter at the edge of the first geometric distribution.
  • the filter types of the brightness filter and the chrominance filter may be as shown in FIG. 6 to FIG.
  • the filter with 9 ⁇ 9 diamond taps, 7 ⁇ 7 diamond taps and 5 ⁇ 5 diamond taps shown in Fig. 8 should understand the filter distribution in the 9 ⁇ 9 diamond taps and the filter distribution in the 7 ⁇ 7 diamond taps.
  • the filter distributions in the 5 ⁇ 5 diamond taps are similar to each other in geometry.
  • the chroma filter and the luma filter can also be other types of filters.
  • the same chrominance filter can be used when filtering the first chrominance pixel and the second chrominance pixel of the same sampling position.
  • the brightness filter and the chrominance filter are respectively used to enter the brightness pixel and the chrominance pixel.
  • the filtering process is performed.
  • the filter coefficients of the chroma pixels can be determined according to the filter coefficients of the luma pixels, so that only the filter coefficients of the luma pixels need to be transmitted, and the filter coefficients of the chroma pixels can be filtered according to the luma pixels.
  • the coefficient is determined to save the transmitted code rate.
  • the encoding end may determine the filter coefficients of the chroma pixels according to the filter coefficients of the luma pixels, and encode only the filter coefficients of the luma pixels, instead of the chroma pixels.
  • the filter coefficients are encoded to reduce the code stream and improve the encoding and decoding efficiency.
  • the decoder can acquire the filter coefficients of the luminance filter according to the code stream, and then determine the filter coefficients of the chroma filter according to the filter coefficients of the luminance filter.
  • determining, according to the filter coefficient of the brightness filter, a filter coefficient of the chroma filter used when performing filtering processing on the chroma pixel of the image to be processed including: filtering according to the first type in the brightness filter The coefficient of the third type of filter coefficients in the chroma filter is determined; and the fourth type of filter coefficients in the chroma filter is determined according to the second type of filter coefficients in the luma filter.
  • the fourth type of filter coefficient is a filter coefficient at a second geometric distribution edge of the chrominance filter
  • the third filter coefficient is a filter of the chromaticity filter other than the fourth type of filter coefficient a coefficient
  • the first type of filter coefficient being the same filter coefficient as the position of the geometric center of the first geometric distribution and the position of a third type of filter coefficient relative to the geometric center of the second geometrical distribution
  • the second type of filter The coefficients are filter coefficients in the luminance filter other than the first type of filter coefficients.
  • the filter coefficient at the center of the chrominance filter that is, the position of the geometric center of the second geometrical distribution, can be determined according to the filter coefficient at the center (where the center can be understood as non-peripheral) in the luminance filter.
  • the filter coefficients determine the filter coefficients at the edges of the second geometric distribution in the chrominance filter based on the filter coefficients in the luminance filter that are relatively at the edges of the first geometric distribution.
  • the L20 point is a filter coefficient at a geometric center position, also referred to herein as a center filter coefficient.
  • L0, L1, L2, L3, L4, L8, etc. are filter coefficients that are relatively located at the edges of the geometric distribution, and also become filter coefficients located at the periphery in this paper. It should be understood that L2 is not located at the edge of the geometric distribution, but is closer to the edge with respect to the filter coefficient of the center, so it is called a filter coefficient that is relatively located at the edge of the geometric distribution.
  • determining the third type of filter coefficients in the chroma filter coefficients according to the first type of filter coefficients in the luma filter may include: selecting the first luma filter coefficients of the first type of filter coefficients The value is assigned to the first chrominance filter coefficient of the third type of filter coefficients, wherein the position of the first chrominance filter coefficient relative to the geometric center of the second geometric distribution and the first luminance filter coefficient are relative to the first geometry
  • the geometric center of the distribution has the same position, that is, any one of the first type of filter coefficients is used as the chrominance filter coefficient of the third type of filter coefficient, wherein the chrominance filter coefficient is relative to
  • the position of the center filter coefficient of the chroma filter is the same as the position of the luma filter coefficient with respect to the center filter coefficient of the luma filter.
  • the chrominance filter determined by the luminance filter can be used to filter the chrominance pixels to obtain better filtering. effect.
  • determining a fourth type of filter coefficient of the chroma filter according to the second type of filter coefficients of the luma filter comprising: using a second luma filter of the second type of filter coefficients The value of the coefficient is added to the value of the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient as the fourth category a value of a second chrominance filter coefficient in the filter coefficient, wherein a position of the second chrominance filter coefficient relative to the geometric center in the second geometric distribution is relative to the second luminance filter coefficient in the first geometric distribution The position in the geometric center is the same, that is, the sum of any one of the second type of filter coefficients and the filter coefficient adjacent to the third filter coefficient is used as the color in the fourth type of filter coefficient
  • the filter coefficient, wherein the position of the fourth filter coefficient relative to the center filter coefficient of the chroma filter is the same as the position of the third filter coefficient with respect to the center filter coefficient of the luminance filter.
  • the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient includes: adjacent to the second luma filter coefficient in the first geometrical distribution or interval K (K is greater than or equal to The second type of filter coefficient of an integer of 1.
  • the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient includes: adjacent to or spaced apart from the second luma filter coefficient in the first geometrical distribution, and is opposite A second type of filter coefficient having a distance from a geometric center of the first geometric distribution that is further than a distance of the second luminance filter coefficient from a geometric center of the first geometric distribution, wherein K is an integer greater than or equal to one.
  • the at least one third luma filter coefficient may be a second type of filter coefficient that is further from the geometric center of the first geometrical distribution among the filter coefficients around the second luma filter coefficient.
  • K 1 above
  • there is another filter coefficient between the two filter coefficients on the two-dimensional plane For example, in FIG. 6, the interval between L0 and L6 is 1.
  • the value of K above may also be an integer greater than 1.
  • the filter coefficients adjacent to the third filter coefficient may be filter coefficients adjacent to the third filter coefficient and located at the periphery of the third filter coefficient.
  • the method of FIG. 5 as an embodiment further includes: determining that the number of taps of the brightness filter is greater than or equal to a preset value.
  • the chroma filter coefficients can be determined according to the luminance filter coefficients according to the method of FIG.
  • the third type filter coefficient and the fourth type filter coefficient in the chrominance filter coefficients are determined in detail according to the first type of filter coefficients and the second type of filter coefficients in the luminance filter. .
  • the luminance filter is a filter with a 9 x 9 diamond tap (as shown in Figure 6) and the chroma filter is a filter with a 5 x 5 diamond tap (as shown in Figure 9).
  • the third type of filter coefficients are specifically C6, C2 and C5
  • the fourth type of filter coefficients are specifically C0, C1, C3 and C4
  • the first type of filter coefficients are specifically L20, L12 and L19
  • the coefficient of the device is specifically L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L13, L14, L15, L16, L17 and L18.
  • the relative positions of the first type of filter coefficients (L20, L12, L19) in the luminance filter are the same as the relative positions of the third type of filter coefficients (C6, C2, C5) in the chrominance filter, respectively.
  • the relative positions of L6, L11, L13, and L18 in the second type of filter coefficients in the first brightness filter are respectively compared with the fourth type of filter coefficients C0,
  • the relative positions of C1, C3, and C4 in the chrominance filter are the same.
  • the relative positions of C6, C2 and C5 in the chroma filter are the same as the relative positions of L20, L12 and L19 in the luma filter, and the value of the correlation coefficient in the luma filter can be directly determined as the chroma filter.
  • the filter coefficient of the corresponding position in the device is the same as the relative positions of L20, L12 and L19 in the luma filter, and the value of the correlation coefficient in the luma filter can be directly determined as the chroma filter.
  • the sum of L6 at the same position as C0 and L0, L1, L2, and L3 at the periphery of L6 is taken as C0;
  • the sum of L11 at the same position as C1 and L4, L5, and L10 at the periphery of L11 is taken as C1;
  • the sum of L3 at the same position of C3 and L7, L8, and L14 at the periphery of L13 is C3;
  • the sum of L18 at the same position as C4 and L9, L15, L16, and L17 at the periphery of L18 is taken as C4.
  • C0-C6 a variety of other methods can be used for the calculation of C0-C6, such as:
  • the luminance filter is a filter with a 7 x 7 diamond tap (as shown in Figure 7) and the chroma filter is a filter with a 5 x 5 diamond tap (as shown in Figure 9).
  • the third type of filter coefficients are specifically C6, C2 and C5
  • the fourth type of filter coefficients are specifically C0, C1, C3 and C4
  • the first type of filter coefficients are specifically M12, M6 and M11
  • the second type of filtering The coefficients are specifically M0, M1, M2, M3, M4, M5, M7, M8, M9, and M10.
  • the relative positions of the first type of filter coefficients (M12, M6, M11) in the luminance filter are the same as the relative positions of the third type of filter coefficients (C6, C2, C5) in the chrominance filter, respectively.
  • the relative positions of M2, M5, M7, and M10 in the second type of filter coefficients in the second luminance filter are respectively compared with the fourth type of filter coefficients C0,
  • the relative positions of C1, C3, and C4 in the chrominance filter are the same.
  • the relative positions of C6, C2 and C5 in the chroma filter are the same as the relative positions of M12, M6 and M11 in the luma filter, and the value of the correlation coefficient in the luma filter can be directly determined as the chroma filter.
  • the filter coefficient of the corresponding position in the device is the same as the relative positions of M12, M6 and M11 in the luma filter, and the value of the correlation coefficient in the luma filter can be directly determined as the chroma filter.
  • the sum of M2 at the same position as C0 and M0 at the periphery of M6 is taken as C0; the sum of M5 at the same position as C1 and M1 and M4 at the periphery of M5 is taken as C1; M7 and M7 at the same position as C3; The sum of the peripheral M3 and M8 is C3; the sum of M10 at the same position as C4 and M9 at the periphery of M10 is taken as C4.
  • both the luminance filter and the chrominance filter are filters of 5 ⁇ 5 diamond taps, as shown in FIGS. 9 and 10, it is assumed that the filter shown in FIG. 9 is a luminance filter, and the filter shown in FIG. 10 is The chroma filter, then, since the shape of the chroma filter and the luma filter are identical, the filter coefficients of the luma filter can be directly determined as the filter coefficients of the corresponding positions in the chroma filter. That is, the filter coefficients C0-C6 of the luminance filter are directly determined as the filter coefficients N0-N6 of the chrominance filter, respectively.
  • the filter of 5 ⁇ 5 diamond tap is only taken as an example here.
  • the filter coefficients of the luminance filter can also be directly determined as colors.
  • the filter coefficient at the corresponding position in the degree filter can also be directly determined as colors.
  • the method of FIG. 5 further includes: determining a number of taps of the luma filter; determining filter coefficients of the chroma filter according to filter coefficients of the luma filter, including: in the luma filter In the case where the number of taps is smaller than the preset value, the filter coefficient of the luminance filter is used as the chroma filter coefficient of the chroma filter.
  • using the filter coefficient of the luma filter as the chroma filter coefficient of the chroma filter includes: using a fourth luma filter coefficient in the luma filter as the fourth in the chroma filter a chroma filter coefficient, wherein a position of the fourth chroma filter coefficient relative to a geometric center in the second geometric distribution and the fourth luma filter coefficient are relative to the fourth geometric filter in the first geometrical distribution
  • the position of the geometric center is the same, that is, any one of the filter coefficients (fourth brightness filter coefficient) in the luminance filter is used as the fourth chrominance filter coefficient in the chrominance filter, wherein the fourth chrominance filter coefficient
  • the position of the center filter coefficient with respect to the chroma filter is the same as the position of the fourth luma filter coefficient with respect to the center filter coefficient of the luma filter.
  • the filter coefficient of the luminance filter can be directly used as the filter coefficient of the chroma filter (in this case, the same filter is used for filtering the luminance pixel and the chroma pixel)
  • the process of determining the filter coefficients of the chroma filter is simplified.
  • the luminance filter is a 7 ⁇ 7 diamond tap filter
  • the number of taps of the luminance filter is less than a preset value
  • the chroma filter is also a 7 ⁇ 7 diamond tap filter in determining the chroma filter.
  • the filter coefficients at the corresponding positions in the luminance filter can be directly determined as the filter coefficients in the chroma filter.
  • FIG. 7 and FIG. 8 it is assumed that the filter coefficient in FIG. 7 is the filter coefficient of the luminance filter, and the filter coefficient in FIG. 8 is the filter coefficient in the chroma filter, then M0- The value of M12 is taken as the value of L0-L12, respectively.
  • the filter coefficient of the device It is also possible to directly determine the filter coefficients of the corresponding positions in the luminance filter as the filter coefficients in the chroma filter. As shown in FIG. 8 and FIG. 9, it is assumed that the filter coefficient in FIG. 8 is the filter coefficient of the luminance filter, and the filter coefficient in FIG. 9 is the filter coefficient in the chroma filter, then C0- The value of C6 is taken as the value of N0-N6, respectively.
  • the method of FIG. 5 further includes: classifying the luma pixels to obtain a plurality of luma pixels; classifying the chroma pixels to obtain a plurality of chroma pixels, wherein the plurality of chromas
  • the categorization of the chrominance pixel class of the pixel class is the same as the categorization of the luminance pixel class of the same sampling position; the brightness filter identification information of the brightness pixel is determined, wherein the brightness filter identification information is used to indicate whether the brightness pixel is subjected to brightness filtering;
  • the chroma filter identification information of the chroma pixel is determined, and the chroma filter identification information is used to indicate whether chroma filtering is performed on the chroma pixel.
  • the method of FIG. 5 further includes: classifying the luma pixels to obtain a plurality of luma pixels; classifying the chroma pixels to obtain a plurality of chroma pixels, wherein the plurality of chromas
  • the classification of any one of the pixel classes of the pixel class is the same as the class of the luminance pixel class of the same sampling position; determining the brightness filtering identification information of the brightness pixel, wherein the brightness filtering identification information is used to indicate the brightness pixel and the corresponding sampling position
  • the chroma pixels are filtered.
  • the filtering process of the chroma pixels multiplexes the luma filtering identification information.
  • the same control is applied to the chrominance pixels and the luminance pixels at the same sampling position. If the luminance pixels are filtered, the chrominance pixels of the same sampling position as the luminance pixels are also filtered, if the luminance pixels are Without filtering, the chrominance pixels at the same sampling position as the luminance pixels are also not filtered.
  • four types of luma pixels are obtained by classifying pixels of an image, wherein luma filtering identification information of the first to third luma pixels is on, and luma filtering identification information of the fourth type of luma pixels.
  • luma filtering identification information of the first to third luma pixels is on
  • luma filtering identification information of the fourth type of luma pixels For the off, that is, the first to third types of luma pixels are filtered, and the fourth type of luma pixels are not filtered.
  • the chrominance pixels (Cb or Cr) in the image that are at the same sampling position as the luma pixels are divided into the same class as the luma pixels, that is, in the same sampling position as the first to fourth types of luma pixels in the image.
  • the chrominance pixels are divided into the first to fourth chrominance pixels, and the classification result of the finally obtained chrominance pixels is as shown in FIG. Since the first to third types of luminance pixels are subjected to filtering processing, the fourth type of luminance pixels are not subjected to filtering processing, and therefore, the first to third types of chrominance pixels (Cb or Cr) are also subjected to filtering processing, and the fourth type The chroma pixels are not filtered.
  • the texture directivity D of the image region corresponding to the luma pixel can be calculated according to the following steps:
  • the gradient g h in the horizontal direction of the image region corresponding to the luminance pixel, the gradient g v in the vertical direction, and the gradients g d1 , g d2 in the two diagonal directions are calculated as follows:
  • V k,l
  • R(k,l) is the coordinate of the pixel point of the preset position of the brightness pixel
  • k is the abscissa of the pixel point of the preset position
  • l is the ordinate of the pixel point of the preset position
  • R(k-1, l+1), R(k+1, l-1) is the pixel of the eight neighbors of the pixel point R(k, l) at the preset position
  • i, j, a, b is an integer, ia ⁇ k ⁇ i + b, ja ⁇ l ⁇ j + b.
  • step 3 If Then go to step 3), otherwise go to step 4)
  • the intensity of the change in the image area corresponding to the luminance pixel It can be calculated in the following way:
  • A is further quantized to an integer in [0, 4], and the quantized value is recorded as
  • the luminance pixels of the image are classified, and according to the formula, the luminance pixels of the image can be divided into 25 classes, and therefore, there can be corresponding 25 sets of adaptive filter coefficients.
  • the method of FIG. 5 when the method of FIG. 5 is applied to a decoder, before determining the filter coefficients of the chroma filter according to the filter coefficients of the luma filter, the method of FIG. 5 further includes: parsing the code. Stream, obtain the filter coefficients of the luminance filter.
  • the decoder determines the filter coefficients of the chroma filter by the filter coefficients of the luma filter, instead of acquiring the filter coefficients of the chroma filter by the code stream.
  • the method of FIG. 5 when the method of FIG. 5 is applied to an encoder, the method of FIG. 5 further includes encoding the filter coefficients of the luminance filter.
  • the encoder only needs to encode the filter coefficients of the luminance filter during encoding, and does not need to encode the filter coefficients of the chroma filter, which saves the code stream that needs to be transmitted.
  • FIG. 12 and FIG. 13 can implement the respective steps of the method of image filtering described above, and for the sake of brevity, the repeated description is appropriately omitted below.
  • FIG. 12 is a schematic block diagram of an image filtering apparatus according to an embodiment of the present application.
  • the image filtering device 1200 of FIG. 12 can perform the image filtering method of FIG. 5 described above, and the image filtering device 1200 includes:
  • a determining module 1210 configured to determine a filter coefficient of the chroma filter according to a filter coefficient of the brightness filter, wherein the brightness filter and the chroma filter are respectively used for a brightness pixel and a color of the image to be processed Filtering processing, all filter coefficients of the luminance filter exhibiting a first geometric distribution, all filter coefficients of the chroma filter exhibiting a second geometric distribution, the first geometric distribution and the second The geometric distribution is a similar pattern, and the filter coefficients of the chroma filter at the edge of the second geometric distribution are calculated by one or more filter coefficients of the luminance filter at the edge of the first geometric distribution;
  • the filtering module 1220 is configured to perform the filtering process on the luma pixel and the chroma pixel, respectively, by using the luma filter and the chroma filter.
  • the filter coefficient of the chroma filter can be determined according to the filter coefficient of the luma filter, so that only the code stream corresponding to the filter coefficient of the luma filter needs to be transmitted when the code stream is transmitted, which can save transmission.
  • the stream of code can be determined according to the filter coefficient of the luma filter, so that only the code stream corresponding to the filter coefficient of the luma filter needs to be transmitted when the code stream is transmitted, which can save transmission.
  • the determining module 1210 is specifically configured to: determine, according to the first type of filter coefficients in the luma filter, a third type of filter coefficients in the chroma filter; a second type of filter coefficient in the luminance filter, determining a fourth type of filter coefficient in the chrominance filter; wherein the fourth type of filter coefficient is in the chrominance filter a filter coefficient of a second geometric distribution edge, the third filter coefficient being a filter coefficient of the chroma filter other than the fourth type of filter coefficient, the first type of filter coefficient
  • the second type of filter is a filter coefficient that is the same as a position of a geometric center of the first geometrical distribution with respect to a geometric center of the third type of filter coefficient with respect to a geometric center of the second geometrical distribution
  • the coefficients are filter coefficients of the luminance filter other than the first type of filter coefficients.
  • the determining module 1210 is specifically configured to: assign a value of a first luma filter coefficient of the first type of filter coefficients to a first one of the third type of filter coefficients a chroma filter coefficient, wherein a position of the first chroma filter coefficient relative to a geometric center of the second geometric distribution and a geometric center of the first luma filter coefficient relative to the first geometrical distribution The same location.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter is a filter having a 5 ⁇ 5 diamond tap
  • the first geometric distribution is 9. ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the first type of filter coefficients include L20, L12, and L19
  • the third type of filter coefficients include C6, C2, and C5, wherein
  • the filter coefficients of the luminance filter are sequentially L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12 in the raster scan order of the 9 ⁇ 9 diamond distribution.
  • the filter coefficients of the chrominance filter are sequentially C0, C1, C2, C3, C4, C5, C6, C5, C4, C3 in the raster scan order in the 5 ⁇ 5 diamond distribution.
  • C2, C1, C0, L19 position relative to L20 and C5 relative to C6 position Similarly, the determining module 1210 is specifically configured to: use L20, L12, and L19 as C6, C2, and C5, respectively.
  • the determining module 1210 is specifically configured to: have a value of a second luma filter coefficient of the second type of filter coefficients, and have a neighborhood with the second luma filter coefficient a value of at least one third luma filter coefficient of the relationship is added as a value of a second chroma filter coefficient of the fourth type of filter coefficients, wherein the second chroma filter coefficient is The position in the second geometrical distribution relative to the geometric center is the same as the position of the second luma filter coefficient in the first geometrical distribution relative to the geometric center.
  • the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient includes: the second luma filter coefficient is at the first The second type of filter coefficients adjacent or at intervals K in the geometric distribution, wherein K is an integer greater than or equal to 1.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter is a filter having a 5 ⁇ 5 diamond tap
  • the first geometric distribution is 9. ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the second type of filter coefficients include L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11 L13, L14, L15, L16, L17, and L18
  • the fourth type of filter coefficients including C0, C1, C3, and C4, wherein filter coefficients of the luminance filter are in the 9 ⁇ 9 diamond distribution
  • the determining module 1210 is further configured to: determine that the number of taps of the brightness filter is greater than or equal to a preset value.
  • the determining module 1210 is specifically configured to: determine a number of taps of the brightness filter; and if the number of taps of the brightness filter is less than a preset value, filter the brightness filter The coefficient is used as the chroma filter coefficient of the chroma filter.
  • the determining module 1210 is specifically configured to: use a fourth luma filter coefficient in the luma filter as a fourth chroma filter coefficient in the chroma filter, where The position of the fourth chrominance filter coefficient relative to the geometric center in the second geometric distribution is the same as the position of the fourth luminance filter coefficient in the first geometric distribution relative to the geometric center.
  • the image filtering apparatus 1200 further includes:
  • a classifying module 1230 configured to classify the brightness pixels to obtain a plurality of brightness pixel classes
  • the classifying module 1230 is further configured to classify the chrominance pixels to obtain a plurality of chrominance pixel classes, wherein the categorization of any one of the plurality of chrominance pixel classes and the same sampling position
  • the brightness pixel class has the same category
  • the determining module 1210 is specifically configured to: determine luma filtering identifier information of the luma pixel, where the luma filtering identifier information is used to indicate that the filtering process is performed on the luma pixel and the chroma pixel of the corresponding sampling position.
  • the image filtering device 1200 is applied to a decoder, and the image filtering device 1200 further includes:
  • the decoding module 1240 is configured to parse the code stream and obtain filter coefficients of the brightness filter.
  • the image filtering device 1200 is applied to an encoder, and the image filtering device 1200 further includes:
  • the encoding module 1250 is configured to encode the filter coefficients of the brightness filter.
  • FIG. 13 is a schematic block diagram of an image filtering apparatus according to an embodiment of the present application.
  • the image filtering device 1300 of FIG. 13 can perform the image filtering method of FIG. 5 described above, and the image filtering device 1300 includes:
  • a memory 1310 configured to store a program
  • the processor 1320 is configured to execute a program stored in the memory 1310. When the program is executed, the processor 1320 is specifically configured to: determine a filter coefficient of the chroma filter according to a filter coefficient of the brightness filter, where The luminance filter and the chrominance filter are respectively used for filtering processing the luminance pixel and the chrominance pixel of the image to be processed, and all the filter coefficients of the luminance filter exhibit a first geometrical distribution, the chrominance filter All of the filter coefficients exhibit a second geometric distribution, the first geometric distribution and the second geometric distribution are similar patterns, and the filter coefficients of the chroma filter at the edge of the second geometric distribution are one or more Filter coefficients of the luminance filter at the edge of the first geometric distribution are calculated; and the luminance processing is performed on the luminance pixel and the chrominance pixel by using the luminance filter and the chrominance filter, respectively.
  • the filter coefficient of the chroma filter can be determined according to the filter coefficient of the luma filter, so that only the code stream corresponding to the filter coefficient of the luma filter needs to be transmitted when the code stream is transmitted, which can save transmission.
  • the stream of code can be determined according to the filter coefficient of the luma filter, so that only the code stream corresponding to the filter coefficient of the luma filter needs to be transmitted when the code stream is transmitted, which can save transmission.
  • the processor 1320 is specifically configured to: determine, according to the first type of filter coefficients in the luma filter, a third type of filter coefficients in the chroma filter; a second type of filter coefficient in the luminance filter, determining a fourth type of filter coefficient in the chrominance filter; wherein the fourth type of filter coefficient is in the chrominance filter a filter coefficient of a second geometric distribution edge, the third filter coefficient being a filter coefficient of the chroma filter other than the fourth type of filter coefficient, the first type of filter coefficient
  • the second type of filter is a filter coefficient that is the same as a position of a geometric center of the first geometrical distribution with respect to a geometric center of the third type of filter coefficient with respect to a geometric center of the second geometrical distribution
  • the coefficients are filter coefficients of the luminance filter other than the first type of filter coefficients.
  • the processor 1320 is specifically configured to: assign a value of a first luma filter coefficient of the first type of filter coefficients to a first one of the third type of filter coefficients a chroma filter coefficient, wherein a position of the first chroma filter coefficient relative to a geometric center of the second geometric distribution and a geometric center of the first luma filter coefficient relative to the first geometrical distribution The same location.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter is a filter having a 5 ⁇ 5 diamond tap
  • the first geometric distribution is 9. ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the first type of filter coefficients include L20, L12, and L19
  • the third type of filter coefficients include C6, C2, and C5, wherein
  • the filter coefficients of the luminance filter are sequentially L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12 in the raster scan order of the 9 ⁇ 9 diamond distribution.
  • the filter coefficients of the chrominance filter are sequentially C0, C1, C2, C3, C4, C5, C6, C5, C4, C3 in the raster scan order in the 5 ⁇ 5 diamond distribution.
  • the processor 1320 is specifically configured to: use L20, L12, and L19 as C6, C2, and C5, respectively.
  • the processor 1320 is specifically configured to: have a value of a second luma filter coefficient of the second type of filter coefficients, and have a neighborhood with the second luma filter coefficient a value of at least one third luma filter coefficient of the relationship is added as a value of a second chroma filter coefficient of the fourth type of filter coefficients, wherein the second chroma filter coefficient is The position in the second geometrical distribution relative to the geometric center is the same as the position of the second luma filter coefficient in the first geometrical distribution relative to the geometric center.
  • the at least one third luma filter coefficient having a neighborhood relationship with the second luma filter coefficient includes: the second luma filter coefficient is at the first The second type of filter coefficients adjacent or at intervals K in the geometric distribution, wherein K is an integer greater than or equal to 1.
  • the luminance filter is a filter having a 9 ⁇ 9 diamond tap
  • the chroma filter is a filter having a 5 ⁇ 5 diamond tap
  • the first geometric distribution is 9. ⁇ 9 diamond distribution
  • the second geometric distribution is a 5 ⁇ 5 diamond distribution
  • the second type of filter coefficients include L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11 L13, L14, L15, L16, L17, and L18
  • the fourth type of filter coefficients including C0, C1, C3, and C4, wherein filter coefficients of the luminance filter are in the 9 ⁇ 9 diamond distribution
  • the processor 1320 is further configured to: determine that the number of taps of the brightness filter is greater than or equal to a preset value.
  • the processor 1320 is specifically configured to: determine a number of taps of the luma filter; and if the number of taps of the luma filter is less than a preset value, filter the luma filter The coefficient is used as the chroma filter coefficient of the chroma filter.
  • the processor 1320 is specifically configured to: use a fourth luma filter coefficient in the luma filter as a fourth chroma filter coefficient in the chroma filter, where The position of the fourth chrominance filter coefficient relative to the geometric center in the second geometric distribution is the same as the position of the fourth luminance filter coefficient in the first geometric distribution relative to the geometric center.
  • the processor 1320 is specifically configured to: classify the luma pixels to obtain a plurality of luma pixels, and classify the chroma pixels to obtain a plurality of chroma pixels.
  • the classification of any one of the plurality of chroma pixel classes is the same as the class of the luma pixel class of the same sampling position; determining luma filtering identification information of the luma pixel, wherein the luma filtering identifier The information is used to indicate that the filtering process is performed on the luma pixels and the chroma pixels of the corresponding sampling positions.
  • the image filtering device 1300 is applied to a decoder, and the processor 1320 is further configured to parse a code stream, and acquire filter coefficients of the brightness filter.
  • the image filtering device 1300 is applied to an encoder, and the processor 1320 is further configured to encode filter coefficients of the luminance filter.
  • image filtering device 1200 and image filtering device 1300 may be specifically located in a codec device or a codec, and the codec device or codec may also perform the image filtering method described above.
  • a codec system composed of a codec device and a codec device will be described in detail below with reference to FIGS. 14 to 16. It should be understood that the codec device and the codec system of FIGS. 14 to 16 are capable of performing the image filtering method of FIG.
  • FIG. 14 and 15 illustrate a codec device 50 of an embodiment of the present application, which may be a mobile terminal or user equipment of a wireless communication system. It should be understood that embodiments of the present application can be implemented in any electronic device or device that may require encoding and/or decoding of video images.
  • the codec device 50 may include a housing 30 for incorporating and protecting the device, a display 32 (which may specifically be a liquid crystal display), a keypad 34.
  • Codec device 50 may include a microphone 36 or any suitable audio input, which may be a digital or analog signal input.
  • the codec device 50 may also include an audio output device, which in the embodiment of the present application may be any of the following: an earphone 38, a speaker, or an analog audio or digital audio output connection.
  • Codec device 50 may also include battery 40, and in other embodiments of the present application, the device may be powered by any suitable mobile energy device, such as a solar cell, fuel cell, or clock mechanism generator.
  • the device may also include an infrared port 42 for short-range line of sight communication with other devices.
  • codec device 50 may also include any suitable short range communication solution, such as a Bluetooth wireless connection or a USB/FireWire wired connection.
  • Codec device 50 may include a controller 56 or processor for controlling codec device 50.
  • the controller 56 can be coupled to a memory 58, which in the embodiments of the present application can store data in the form of data and audio in the form of images, and/or can also store instructions for execution on the controller 56.
  • the controller 56 can also be coupled to a codec 54 suitable for implementing encoding and decoding of audio and/or video data or assisted encoding and decoding by the controller 56.
  • the codec device 50 may also include a card reader 48 and a smart card 46 for providing user information and for providing authentication information for authenticating and authorizing users on the network, such as a Universal Integrated Circuit Card (UICC) and a UICC. Reader.
  • a card reader 48 for providing user information and for providing authentication information for authenticating and authorizing users on the network, such as a Universal Integrated Circuit Card (UICC) and a UICC. Reader.
  • UICC Universal Integrated Circuit Card
  • UICC Universal Integrated Circuit Card
  • the codec device 50 may also include a radio interface circuit 52 coupled to the controller and adapted to generate, for example, a wireless communication signal for communicating with a cellular communication network, a wireless communication system, or a wireless local area network.
  • the codec device 50 may also include an antenna 44 coupled to the radio interface circuit 52 for transmitting radio frequency signals generated at the radio interface circuit 52 to other device(s) and for receiving radio frequency signals from other device(s) .
  • codec device 50 includes a camera capable of recording or detecting a single frame, and codec 54 or controller receives these single frames and processes them. In some embodiments of the present application, codec device 50 may receive video image data to be processed from another device prior to transmission and/or storage. In some embodiments of the present application, codec device 50 may receive images for encoding/decoding over a wireless or wired connection.
  • FIG. 16 is a schematic block diagram of a video codec system 10 according to an embodiment of the present application.
  • the video codec system 10 includes a source device 12 and a destination device 14.
  • Source device 12 produces encoded video data.
  • source device 12 may be referred to as a video encoding device or a video encoding device.
  • Destination device 14 may decode the encoded video data produced by source device 12.
  • destination device 14 may be referred to as a video decoding device or a video decoding device.
  • Source device 12 and destination device 14 may be examples of video codec devices or video codec devices.
  • Source device 12 and destination device 14 may include desktop computers, mobile computing devices, notebook (eg, laptop) computers, tablet computers, set top boxes, smart phones, and the like, televisions, cameras, display devices, digital media players, Video game console, onboard computer, or other similar device.
  • Channel 16 may include one or more media and/or devices capable of moving encoded video data from source device 12 to destination device 14.
  • channel 16 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real time.
  • source device 12 may modulate the encoded video data in accordance with a communication standard (eg, a wireless communication protocol) and may transmit the modulated video data to destination device 14.
  • the one or more communication media may include wireless and/or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines.
  • RF radio frequency
  • the one or more communication media may form part of a packet-based network (eg, a local area network, a wide area network, or a global network (eg, the Internet)).
  • the one or more communication media may include routers, switches, base stations, or other devices that facilitate communication from source device 12 to destination device 14.
  • channel 16 can include a storage medium that stores encoded video data generated by source device 12.
  • destination device 14 can access the storage medium via disk access or card access.
  • the storage medium may include a variety of locally accessible data storage media, such as Blu-ray Disc, DVD, CD-ROM, flash memory, or other suitable digital storage medium for storing encoded video data.
  • channel 16 can include a file server or another intermediate storage device that stores encoded video data generated by source device 12.
  • destination device 14 may access the encoded video data stored at a file server or other intermediate storage device via streaming or download.
  • the file server may be a server type capable of storing encoded video data and transmitting the encoded video data to the destination device 14.
  • the file server can include a web server (eg, for a website), a file transfer protocol (FTP) server, a network attached storage (NAS) device, and a local disk drive.
  • FTP file transfer protocol
  • NAS network attached storage
  • Destination device 14 can access the encoded video data via a standard data connection (e.g., an internet connection).
  • a standard data connection e.g., an internet connection.
  • An instance type of a data connection includes a wireless channel (eg, a Wi-Fi connection), a wired connection (eg, DSL, cable modem, etc.), or both, suitable for accessing encoded video data stored on a file server. combination.
  • the transmission of the encoded video data from the file server may be streaming, downloading, or a combination of both.
  • the codec method of the present application is not limited to a wireless application scenario.
  • the codec method may be applied to video codec supporting multiple multimedia applications such as: aerial television broadcasting, cable television transmission, satellite television transmission, Streaming video transmission (e.g., via the Internet), encoding of video data stored on a data storage medium, decoding of video data stored on a data storage medium, or other application.
  • video codec system 10 may be configured to support one-way or two-way video transmission to support applications such as video streaming, video playback, video broadcasting, and/or video telephony.
  • source device 12 includes video source 18, video encoder 20, and output interface 22.
  • output interface 22 can include a modulator/demodulator (modem) and/or a transmitter.
  • Video source 18 may include a video capture device (eg, a video camera), a video archive containing previously captured video data, a video input interface to receive video data from a video content provider, and/or a computer for generating video data.
  • Video encoder 20 may encode video data from video source 18.
  • source device 12 transmits the encoded video data directly to destination device 14 via output interface 22.
  • the encoded video data may also be stored on a storage medium or file server for later access by the destination device 14 for decoding and/or playback.
  • destination device 14 includes an input interface 28, a video decoder 30, and a display device 32.
  • input interface 28 includes a receiver and/or a modem.
  • Input interface 28 can receive the encoded video data via channel 16.
  • Display device 32 may be integral with destination device 14 or may be external to destination device 14. In general, display device 32 displays the decoded video data. Display device 32 may include a variety of display devices such as liquid crystal displays (LCDs), plasma displays, organic light emitting diode (OLED) displays, or other types of display devices.
  • LCDs liquid crystal displays
  • OLED organic light emitting diode
  • Video encoder 20 and video decoder 30 may operate in accordance with a video compression standard (eg, the High Efficiency Video Codec H.265 standard) and may conform to the HEVC Test Model (HM).
  • a video compression standard eg, the High Efficiency Video Codec H.265 standard
  • HM HEVC Test Model
  • a textual description of the H.265 standard is published on April 29, 2015, ITU-T.265(V3) (04/2015), available for download from http://handle.itu.int/11.1002/1000/12455 The entire contents of the document are incorporated herein by reference.
  • B corresponding to A means that B is associated with A, and B can be determined according to A.
  • determining B from A does not mean that B is only determined based on A, and that B can also be determined based on A and/or other information.
  • the disclosed systems, devices, and methods may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the functions may be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product.
  • the technical solution of the present application which is essential or contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product, which is stored in a storage medium, including
  • the instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

Abstract

本申请提供了一种图像滤波方法及装置。该方法包括：根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，亮度滤波器和色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，亮度滤波器的全部滤波器系数呈现第一几何分布，色度滤波器的全部滤波器系数呈现第二几何分布，第一几何分布和第二几何分布为相似图形，处于第二几何分布边缘的色度滤波器的滤波器系数由多个处于第一几何分布边缘的亮度滤波器的滤波器系数计算得到；采用亮度滤波器和色度滤波器分别对亮度像素和色度像素进行滤波处理。本申请实施例能够减少码率的传输。

Description

图像滤波方法及装置 技术领域
本申请涉及视频图像编解码技术领域，并且更具体地，涉及一种图像滤波方法及装置。
背景技术
数字视频装置在目前得到了广泛的应用，例如，数字电视、数字直播系统、无线广播系统、个人数字助理(PDA)、膝上型或桌上型计算机、数码相机、数字记录装置、数字媒体播放器、视频游戏装置、视频游戏控制台、蜂窝式或卫星无线电电话、视频会议装置等等。数字视频装置通常采用基于块的混合视频编码框架的视频压缩技术对视频进行压缩，例如从MPEG-1/2到最新的视频编码标准H.265/HEVC，以便于更高效地发射、接收以及存储数字视频信息。
自适应环路滤波(Adaptive loop filter)是视频编解码的重要技术之一，ALF通过对编解码得到的重构图像进行滤波，能够提高重构图像的质量，减少图像的失真。
现有的自适应环路滤波在对图像进行滤波处理时是将亮度像素和色度像素分开处理，并且对亮度像素和色度像素分别传输各自的滤波器系数，这样就会导致需要传送的码率增多。
发明内容
本申请提供一种图像波方法及装置，能够减少码率的传输。
第一方面，提供一种图像滤波方法，该方法包括：根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，所述亮度滤波器和所述色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，所述亮度滤波器的全部滤波器系数呈现第一几何分布，所述色度滤波器的全部滤波器系数呈现第二几何分布，所述第一几何分布和所述第二几何分布为相似图形，处于所述第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于所述第一几何分布边缘的亮度滤波器的滤波器系数计算得到；采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进行所述滤波处理。
色度滤波器的滤波器系数可以根据亮度滤波器的滤波器系数来确定，使得在传输码流时只需要传输亮度滤波器的滤波器系数对应的码流即可，能够节省传输的码流。
结合第一方面，在第一方面的某些实现方式中，所述根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，包括：根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器中的第三类滤波器系数；根据所述亮度滤波器中的第二类滤波器系数，确定所述色度滤波器中的第四类滤波器系数；其中，所述第四类滤波器系数为所述色度滤波器中处于所述第二几何分布边缘的滤波器系数，所述第三滤波器系数为所述色度滤波器中除所述第四类滤波器系数之外的滤波器系数，所述第一类滤波器系数为相对于所述第一几何分布的几何中心的位置与一个所述第三类滤波器系数相对于所述第二几何分布的几何中心的位置相同的滤波器系数，所述第二类滤波器系数为所述亮度滤波器中除所述第一类滤波器系数之外的滤波器系数。
由于亮度滤波器处理的亮度像素与色度滤波器处理的色度像素处于相同的采样位置，因此，利用根据亮度滤波器确定的色度滤波器对色度像素进行滤波处理能够取得较好的滤波效果。
结合第一方面，在第一方面的某些实现方式中，所述根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器系数中的第三类滤波器系数，包括：将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，其中，所述第一色度滤波器系数相对于所述第二几何分布的几何中心的位置与所述第一亮度滤波器系数相对于所述第一几何分布的几何中心的位置相同。
结合第一方面，在第一方面的某些实现方式中，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括L20、L12、L19，所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，包括：将L20、L12以及L19分别作为C6、C2和C5。
结合第一方面，在第一方面的某些实现方式中，所述亮度滤波器为具有7×7菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为7×7菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括M12、M6、M11，所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为M0、M1、M2、M3、M4、M5、M6、M7、M8、M9、M10、M11、M12、M11、M10、M9、M8、M7、M6、M5、M4、M3、M2、M1、M0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，包括：将M12、M6以及M11分别作为C6、C2和C5。
结合第一方面，在第一方面的某些实现方式中，根据所述亮度滤波器的第二类滤波器系数，确定所述色度滤波器的第四类滤波器系数，包括：将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，其中，所述第二色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第二亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
结合第一方面，在第一方面的某些实现方式中，所述与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K的所述第二类滤波器系数，其中，K为大于等于1的整数。
结合第一方面，在第一方面的某些实现方式中，所述与所述第二亮度滤波器系数具 有邻域关系的至少一个第三亮度滤波器系数，包括：与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K，并且相对于第一几何分布的几何中心的距离比所述第二亮度滤波器系数相对于所述第一几何分布的几何中心的距离更远的所述第二类滤波器系数，其中，K为大于等于1的整数。
结合第一方面，在第一方面的某些实现方式中，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，包括：将L1、L2、L3、L0以及L6的和作为C0；将L4、L5、L10以及L11的和作为C1；将L7、L8、L13以及L14的和作为C3；将L9、L15、L16、L17以及L18的和作为C4。
结合第一方面，在第一方面的某些实现方式中，所述亮度滤波器为具有7×7菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为7×7菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括M0、M1、M2、M3、M4、M5、M7、M8、M9以及M10，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为M0、M1、M2、M3、M4、M5、M6、M7、M8、M9、M10、M11、M12、M11、M10、M9、M8、M7、M6、M5、M4、M3、M2、M1、M0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，包括：将M0与M2的和作为C0；将M1、M4以及M5的和作为C1；将M3、M8以及M7的和作为C3；将M9与M10的和作为C4。
结合第一方面，在第一方面的某些实现方式中，所述方法还包括：确定所述亮度滤波器的抽头数目大于或者等于预设值。
结合第一方面，在第一方面的某些实现方式中，所述根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，包括：确定所述亮度滤波器的抽头数目；在所述亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
当亮度滤波器的抽头数目较少时，可以直接将亮度滤波器的滤波器系数作为色度滤波器的滤波器系数(此时，对亮度像素和色度像素采用相同的滤波器进行滤波处理)， 简化了确定色度滤波器的滤波器系数的过程。
结合第一方面，在第一方面的某些实现方式中，所述将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数，包括：将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第四色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
结合第一方面，在第一方面的某些实现方式中，在所述根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数之前，还包括：对所述亮度像素进行分类，得到多个亮度像素类；对所述色度像素进行分类，得到多个色度像素类，其中，所述多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；确定所述亮度像素的亮度滤波标识信息，其中，所述亮度滤波标识信息用于指示对所述亮度像素和对应采样位置的色度像素进行所述滤波处理。。
通过对处于相同采样位置的色度像素和亮度像素采用相同的滤波开关控制，与现有技术中只能选择对整个图片的色度像素(Cb或者Cr)选择是否使用滤波的方式相比，能够对色度像素实现更小粒度的开关控制，从而能够灵活控制对色度像素的滤波处理，可以取得更好的滤波效果。
结合第一方面，在第一方面的某些实现方式中，所述方法应用于解码器，在根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数之前，所述方法还包括：解析码流，获取所述亮度滤波器的滤波器系数。
结合第一方面，在第一方面的某些实现方式中，所述方法应用于编码器，所述方法还包括：对所述亮度滤波器的滤波器系数进行编码。
编码器在编码时只需要对亮度滤波器的滤波器系数进行编码，而不需要对色度滤波器的滤波器系数进行编码，节省了需要传输的码流。
第二方面，提供一种图像滤波装置，所述图像滤波装置包括用于执行所述第一方面或其各种实现方式中的方法的模块。
第三方面，提供一种图像滤波装置，该装置包括：非易失性存储介质，以及中央处理器，所述非易失性存储介质存储有可执行程序，所述中央处理器与所述非易失性存储介质连接，并执行所述可执行程序以实现所述第一方面或其各种实现方式中的方法。
第四方面，提供一种计算机可读介质，所述计算机可读介质存储用于设备执行的程序代码，所述程序代码包括用于执行第一方面或其各种实现方式中的方法的指令。
应理解，本发明第二至第四方面所提供的技术方案与第一方面所提供的技术方案，技术手段一致，技术的有益效果类似，不再赘述。
附图说明
图1是4:4:4采样格式的示意图。
图2是4:2:2采样格式的示意图。
图3是4:1:1采样格式的示意图。
图4是4:2:0采样格式的示意图。
图5是本申请实施例的图像滤波方法的示意性流程图。
图6是9×9菱形抽头的滤波器的示意图。
图7是7×7菱形抽头的滤波器的示意图。
图8是7×7菱形抽头的滤波器的示意图。
图9是5×5菱形抽头的滤波器的示意图。
图10是5×5菱形抽头的滤波器的示意图。
图11是对某图像的亮度像素和色度像素进行分类后得到的分类结果的示意图。
图12是本申请实施例的图像滤波装置的示意性框图。
图13是本申请实施例的图像滤波装置的示意性框图。
图14是本申请实施例的编解码装置的示意性框图。
图15是本申请实施例的编解码装置的示意性图。
图16是本申请实施例的视频编解码系统的示意性框图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述。
为了更好地理解本申请实施例，下面首先介绍一下本申请实施例涉及的YCbCr模型、亮度像素以及色度像素。
YCbCr模型是与RGB模型不同的颜色模型，RGB模型是将亮度和色度放在一起共同进行表示，而YCbCr模型是将亮度和色度分开进行表示。YCbCr模型包括三个分量(Y，Cb，Cr)，其中，Y为亮度分量，Cb为第一色度分量，Cr为第二色度分量(当然，也可将Cr称为第一色度分量，将Cb称为第二色度分量)，第一色度分量和第二色度分量可以统称为色度分量。
因此，在基于YCbCr模型的图像中，图像中的像素(点)包括亮度像素(点)、第一色度像素(点)和第二色度像素(点)，其中，第一色度像素和第二色度像素可以统称为色度像素。
在基于YCbCr模型的图像中，对图像的像素进行采样时有不同的采样格式，下面结合图1至图4分别对4:4:4、4:2:2、4:2:0、4:1:1这几种常见的采样格式进行简单的说明。
在图1至图4中，每个小的矩形表示一个像素，不同的圆形分别表示对像素进行亮度采样，第一色度采样和第二色度采样。
如图1所示，对每个像素均进行亮度采样和色度采样(包括第一色度采样和第二色度采样)。也就是说，在每4个像素中进行4次亮度采样，4次第一色度采样以及4次第二色度采样，这种采用格式叫做4:4:4。
由于人眼对亮度的敏感度要大于对色度的敏感度，因此，一般在YCbCr模型的图像中为了节省码率，在对图像的像素进行采样时，色度采样比例可以小于亮度采样比例(如图2至图4中，对于每一个像素均进行亮度采样，而对于色度采样来说，可以每2个或者每4个像素进行一次色度采样)。
如图2所示，对每个像素均进行亮度采样，在水平方向上，对每2个像素进行一次色度采样。也就是说，在每4个像素中进行4次亮度采样，2次第一色度采样以及2次第二色度采样，这种采样格式叫做4:2:2。在图2中，对于第一色度或者第二色度来说，其采样比例为亮度采样比例的一半。
如图3所示，对每个像素均进行亮度采样，在水平方向上，对每4个像素进行一次色度采样。也就是说，在每4个像素中进行4次亮度采样，1次第一色度采样以及1次第 二色度采样，这种采用格式叫做4:1:1。在图3中，对于第一色度或者第二色度来说，其采样比例为亮度像素采样比例的四分之一。
如图4所示，对每个像素均进行亮度采样，在第一行的像素中，对每2个像素进行一次第一色度采样，在第二行的像素中，对每2个像素进行一次第二色度采样，这种采用格式叫做4:2:0。在图4中，对第一色度和第二色度的采样是分开的，而在图1至图3中，对第一色度和第二色度是一起进行采样的，也就是说，在图1至图3中，对于某个像素来说，如果进行色度采样的话那么就要进行第一色度采样和第二色度采样，而在图4中，对于某个像素来说，如果进行色度采样，那么可以选择进行第一色度采样或者第二色度采样。
应理解，在本申请实施例中，待处理图像的像素的采样类型可以是图1至图4中的任意一种。
现有的自适应环路滤波在对图像的像素进行滤波处理时是将亮度像素和色度像素分开进行处理的，对于亮度像素来说，按照当前亮度像素与周围邻近亮度像素的关系，将亮度像素分成N类，对其中的同一类亮度像素采用同一个自适应滤波器(也就是采用同一组滤波器系数)，对于不同类的亮度像素既可以采用同一个自适应滤波器，也可以采用不同的自适应滤波器。而对于色度像素来说，现有的做法并没有利用当前色度像素与周围邻近色度像素的关系进行分类，而是另外采用了一个自适应滤波器(也就是采用了另外一组组滤波器系数)对整张图片的色度像素进行滤波处理。
由于对亮度像素和色度像素分别采用相应的滤波器进行滤波，那么对色度像素和亮度像素的滤波器系数均要进行传输，这样就会导致传送的码率增多。
因此，本申请实施例提出了一种自适应环路滤波方法，能够根据亮度像素的滤波器系数来确定色度像素的滤波器系数，这样只需要传输亮度像素的滤波器系数即可，而色度像素的滤波器系数可以根据亮度像素的滤波器系数来确定，能够节省传送的码率。
图5是本申请实施例的自适应环路滤波方法的示意性流程图。图5的方法包括：
510、根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数。
其中，上述亮度滤波器用于对待处理图像的亮度像素进行滤波处理。
亮度滤波器的全部滤波器系数呈现第一几何分布，色度滤波器的全部滤波器系数呈现第二几何分布，第一几何分布和第二几何分布为相似图形，处于第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于第一几何分布边缘的亮度滤波器的滤波器系数计算得到，比如上述亮度滤波器和色度滤波器的滤波器类型可以是如图6至图8所示的具有9×9菱形抽头、7×7菱形抽头以及5×5菱形抽头的滤波器，应理解，9×9菱形抽头中的滤波器分布、7×7菱形抽头中的滤波器分布、5×5菱形抽头中的滤波器分布在几何学中互为相似图形，当然，色度滤波器和亮度滤波器也可以是其它类型的滤波器。
另外，上述色度像素可以包括第一色度像素(Cb)和第二色度像素(Cr)。根据亮度滤波器的滤波器系数，确定对色度像素进行滤波处理时采用的色度滤波器的滤波器系数可以是指根据亮度滤波器的滤波器系数，确定对第一色度像素和/或第二色度像素进行滤波处理时采用的色度滤波器。
也就是说在对相同采样位置的第一色度像素和第二色度像素进行滤波处理时可以采用相同的色度滤波器。
520、采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进 行所述滤波处理。
本申请中，能够根据亮度像素的滤波器系数来确定色度像素的滤波器系数，这样只需要传输亮度像素的滤波器系数即可，而色度像素的滤波器系数可以根据亮度像素的滤波器系数来确定，能够节省传送的码率。
具体地，当图5的方法由编码器执行时，编码端可以根据亮度像素的滤波器系数确定色度像素的滤波器系数，并且只对亮度像素的滤波器系数进行编码，而不对色度像素的滤波器系数进行编码，从而能够减少码流，提高编解码效率。
而当图5的方法由解码器执行时，解码器可以根据码流来获取亮度滤波器的滤波器系数，接下来再根据亮度滤波器的滤波器系数来确定色度滤波器的滤波器系数。
可选地，根据所述亮度滤波器的滤波器系数，确定对待处理图像的色度像素进行滤波处理时采用的色度滤波器的滤波器系数，包括：根据亮度滤波器中的第一类滤波器系数，确定色度滤波器中的第三类滤波器系数；根据亮度滤波器中的第二类滤波器系数，确定色度滤波器中的第四类滤波器系数。
其中，上述第四类滤波器系数为色度滤波器中处于第二几何分布边缘的滤波器系数，上述第三滤波器系数为色度滤波器中除第四类滤波器系数之外的滤波器系数，第一类滤波器系数为相对于第一几何分布的几何中心的位置与一个第三类滤波器系数相对于第二几何分布的几何中心的位置相同的滤波器系数，第二类滤波器系数为亮度滤波器中除第一类滤波器系数之外的滤波器系数。
也就是说可以根据亮度滤波器中处于中心(此处的中心可以理解为非外围)的滤波器系数来确定色度滤波器中处于中心的滤波器系数，即第二几何分布的几何中心的位置的滤波器系数，根据亮度滤波器中相对处于第一几何分布边缘的滤波器系数来确定色度滤波器中处于第二几何分布边缘的滤波器系数。
具体地，举例来说，对于9×9菱形抽头滤波器来说，如图6所示，L20点为位于几何中心位置的滤波器系数，本文中也称为中心滤波器系数。L0，L1，L2，L3，L4，L8等为相对位于几何分布边缘的滤波器系数，在本文中也成为位于外围的滤波器系数。应理解，L2没有位于几何分布的边缘，但是相对于中心的滤波器系数，更临近边缘，所以称为相对位于几何分布边缘的滤波器系数。
具体地，在根据亮度滤波器中的第一类滤波器系数确定色度滤波器系数中的第三类滤波器系数，可以包括：将第一类滤波器系数中的第一亮度滤波器系数的值赋予第三类滤波器系数中的第一色度滤波器系数，其中，第一色度滤波器系数相对于第二几何分布的几何中心的位置与第一亮度滤波器系数相对于第一几何分布的几何中心的位置相同，也即，将第一类滤波器系数中的任意一个亮度滤波器系数作为第三类滤波器系数中的色度滤波器系数，其中，色度滤波器系数相对于色度滤波器的中心滤波器系数的位置与亮度滤波器系数相对于亮度滤波器的中心滤波器系数的位置相同。
由于亮度滤波器与色度滤波器分别处理的亮度像素和色度像素处于相同的采样位置，因此，利用根据亮度滤波器确定的色度滤波器对色度像素进行滤波处理能够取得较好的滤波效果。
可选地，作为一个实施例，根据亮度滤波器的第二类滤波器系数，确定色度滤波器的第四类滤波器系数，包括：将第二类滤波器系数中的第二亮度滤波器系数的值和与第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为第四类 滤波器系数中的第二色度滤波器系数的值，其中，第二色度滤波器系数在第二几何分布中相对于几何中心的位置与第二亮度滤波器系数在第一几何分布中相对于几何中心的位置相同，也即，将第二类滤波器系数中的任意一个第三滤波器系数以及第三滤波器系数相邻的滤波器系数的和作为第四类滤波器系数中的色度滤波器系数，其中，第四滤波器系数相对于色度滤波器的中心滤波器系数的位置与第三滤波器系数相对于亮度滤波器的中心滤波器系数的位置相同。
应理解，与第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：与第二亮度滤波器系数在第一几何分布中相邻或间隔为K(K为大于等于1的整数)的第二类滤波器系数。
更具体地，上述与第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：与第二亮度滤波器系数在第一几何分布中相邻或间隔为K，并且相对于第一几何分布的几何中心的距离比第二亮度滤波器系数相对于第一几何分布的几何中心的距离更远的第二类滤波器系数，其中，K为大于等于1的整数。
也就是说，上述至少一个第三亮度滤波器系数可以是第二亮度滤波器系数周围的滤波器系数中距离第一几何分布的几何中心更远的第二类滤波器系数。
应理解，当上述K＝1时表示二维平面上两个滤波器系数间有另一个滤波器系数。例如，在图6中，L0和L6的间隔为1。另外，在一些抽头数目较大的滤波器(如11×11抽头)中，上述K的取值还可以为大于1的整数。
上述第三滤波器系数相邻的滤波器系数可以是与第三滤波器系数相邻，并且处于第三滤波器系数外围的滤波器系数。
可选地，作为一个实施例图5的方法还包括：确定亮度滤波器的抽头数目大于或者等于预设值。
例如，当亮度滤波器的抽头数目大于或者等于5×5时就可以按照图5的方法根据亮度滤波器系数来确定色度滤波器系数。
下面结合具体实例对根据亮度滤波器中的第一类滤波器系数和第二类滤波器系数来确定色度滤波器系数中的第三类滤波器系数和第四类滤波器系数进行详细的说明。
实例一：
亮度滤波器为具有9×9菱形抽头的滤波器(如图6所示)，色度滤波器为具有5×5菱形抽头的滤波器(如图9所示)。那么，第三类滤波器系数具体为C6、C2和C5，第四类滤波器系数具体为C0、C1、C3和C4，第一类滤波器系数具体为L20、L12和L19，第二类滤波器系数具体为L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18。
上述第一类滤波器系数(L20、L12、L19)在亮度滤波器中的相对位置分别与上述第三类滤波器系数(C6、C2、C5)在色度滤波器中的相对位置相同。
对于第二类滤波器系数和第四类滤波器来说，第二类滤波器系数中的L6、L11、L13以及L18在第亮度滤波器中的相对位置分别与第四类滤波器系数C0、C1、C3以及C4在色度滤波器中的相对位置相同。
那么可以得到：
C6＝L20；
C2＝L12；
C5＝L19；
其中，C6、C2以及C5在色度滤波器中的相对位置与L20、L12以及L19在亮度滤波器中的相对位置相同，可以直接将亮度滤波器中的相关系数的值直接确定为色度滤波器中相应位置的滤波器系数。
另外，还可以得到：
C0＝L1+L2+L3+L0+L6；
C1＝L4+L5+L10+L11；
C3＝L7+L8+L14+L13；
C4＝L9+L15+L16+L17+L18。
也就是将与C0处于相同位置的L6以及L6外围的L0、L1、L2以及L3的和作为C0；将与C1处于相同位置的L11以及L11外围的L4、L5以及L10的和作为C1；将与C3处于相同位置的L13以及L13外围的L7、L8以及L14的和作为C3；将与C4处于相同位置的L18以及L18外围的L9、L15、L16以及L17的和作为C4。
在其它实例中，对于C0-C6的计算方式，还可以采用多种其它方法，比如：
C0＝L1+L2+L3+L6；或C0＝L1+L3+L6；或C0＝L6+L2；
C1＝L5+L10+L11；或C1＝L4+L11；
C2＝L12+L16+L20+L11+L13；或C2＝L5+L6+L7+L11+L12+L13+L19+L20+L19；
C3＝L13+L7+L14；或C3＝L8+L13；
C4＝L18+L9+L15+L17；或C4＝L9+L15+L18；或C0＝L17+L18；
C5＝L11+L18+L19+L20+L13；或C5＝L11+L18+L19+L20+L13+L10+L12+L14+L12；
C6＝L19+L20+L19+L12+L12；或C6＝L19+L20+L19+L12+L12+L11+L13+L13+L11。
应理解，上述多种C0-C6的计算方式以及相互组合，在不同的实例中不做限定。
应理解，当色度滤波器的滤波器系数呈现其它几何分布时，同样存在类似的多种计算方式，不做限定。
实例二：
亮度滤波器为具有7×7菱形抽头的滤波器(如图7所示)，色度滤波器为具有5×5菱形抽头的滤波器(如图9所示)。那么，第三类滤波器系数具体为C6、C2和C5，第四类滤波器系数具体为C0、C1、C3和C4，第一类滤波器系数具体为M12、M6以及M11，第二类滤波器系数具体为M0、M1、M2、M3、M4、M5、M7、M8、M9以及M10。
上述第一类滤波器系数(M12、M6、M11)在亮度滤波器中的相对位置分别与上述第三类滤波器系数(C6、C2、C5)在色度滤波器中的相对位置相同。
对于第二类滤波器系数和第四类滤波器来说，第二类滤波器系数中的M2、M5、M7以及M10在第亮度滤波器中的相对位置分别与第四类滤波器系数C0、C1、C3以及C4在色度滤波器中的相对位置相同。
那么可以得到：
C6＝M12；
C2＝M6；
C5＝M11；
其中，C6、C2以及C5在色度滤波器中的相对位置与M12、M6以及M11在亮度滤波器中的相对位置相同，可以直接将亮度滤波器中的相关系数的值直接确定为色度滤波 器中相应位置的滤波器系数。
另外，还可以得到：
C0＝M0+M2；
C1＝M1+M4+M5；
C3＝M3+M8+M7；
C4＝M9+M10。
也就是将与C0处于相同位置的M2以及M6外围的M0的和作为C0；将与C1处于相同位置的M5以及M5外围的M1和M4的和作为C1；将与C3处于相同位置的M7以及M7外围的M3和M8的和作为C3；将与C4处于相同位置的M10以及M10外围的M9的和作为C4。
实例三
当亮度滤波器和色度滤波器均为5×5菱形抽头的滤波器，如图9和图10所示，假设图9所示的滤波器为亮度滤波器，图10所示的滤波器为色度滤波器，那么，由于色度滤波器和亮度滤波器的形状完全相同，可以直接将亮度滤波器的滤波器系数确定为色度滤波器中相应位置的滤波器系数。也就是直接将亮度滤波器的滤波器系数C0-C6分别确定为色度滤波器的滤波器系数N0-N6。
应理解，这里仅仅是以5×5菱形抽头的滤波器为例，当亮度滤波器和色度滤波器均为其它类型的滤波器时，也可以直接将亮度滤波器的滤波器系数确定为色度滤波器中相应位置的滤波器系数。
可选地，作为一个实施例，图5的方法还包括：确定亮度滤波器的抽头数目；根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，包括：在亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
具体地，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数，包括：将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第四色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同，也即将亮度滤波器中的任意一个滤波器系数(第四亮度滤波器系数)作为色度滤波器中的第四色度滤波器系数，其中，第四色度滤波器系数相对于色度滤波器的中心滤波器系数的位置与第四亮度滤波器系数相对于亮度滤波器的中心滤波器系数的位置相同。
当亮度滤波器的抽头数目较少时，可以直接将亮度滤波器的滤波器系数作为色度滤波器的滤波器系数(此时，对亮度像素和色度像素采用相同的滤波器进行滤波处理)，简化了确定色度滤波器的滤波器系数的过程。
例如，当亮度滤波器为7×7菱形抽头的滤波器时，亮度滤波器的抽头数目小于预设值，这时色度滤波器也是7×7菱形抽头的滤波器，在确定色度滤波器的滤波器系数时，可以直接将亮度滤波器中相应位置的滤波器系数确定为色度滤波器中的滤波器系数。如图7和图8所示，假定图7中的滤波器系数为亮度滤波器的滤波器系数，图8中的滤波器系数为色度滤波器中的滤波器系数，那么，可以将M0-M12的值分别作为L0-L12的值。
再如，当亮度滤波器为5×5菱形抽头的滤波器时，亮度滤波器的抽头数目小于预设值，这时色度滤波器也是5×5菱形抽头的滤波器，在确定色度滤波器的滤波器系数时， 也可以直接将亮度滤波器中相应位置的滤波器系数确定为色度滤波器中的滤波器系数。如图8和图9所示，假定图8中的滤波器系数为亮度滤波器的滤波器系数，图9中的滤波器系数为色度滤波器中的滤波器系数，那么，可以将C0-C6的值分别作为N0-N6的值。
可选地，作为一个实施例，图5的方法还包括：对亮度像素进行分类，得到多个亮度像素类；对色度像素进行分类，得到多个色度像素类，其中，多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；确定亮度像素的亮度滤波标识信息，其中，亮度滤波标识信息用于指示对亮度像素是否进行亮度滤波；确定色度像素的色度滤波标识信息，色度滤波标识信息用于指示对色度像素是否进行色度滤波。
可选地，作为一个实施例，图5的方法还包括：对亮度像素进行分类，得到多个亮度像素类；对色度像素进行分类，得到多个色度像素类，其中，多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；确定亮度像素的亮度滤波标识信息，其中，亮度滤波标识信息用于指示对亮度像素和对应采样位置的色度像素进行滤波处理。在该实施例中，色度像素的滤波处理复用亮度滤波标识信息。
通过对处于相同采样位置的色度像素和亮度像素采用相同的滤波开关控制，与现有技术中只能选择对整个图片的色度像素(Cb或者Cr)选择是否使用滤波的方式相比，能够对色度像素实现更小粒度的开关控制，从而能够灵活控制对色度像素的滤波处理，可以取得更好的滤波效果。
也就是说对处于相同采样位置的色度像素和亮度像素采用相同的控制，如果对亮度像素进行滤波，那么就要对与亮度像素相同采样位置的色度像素也进行滤波处理，如果对亮度像素不进行滤波，那么就对与亮度像素相同采样位置的色度像素也不进行滤波处理。
如图11所示，对某图像的像素进行分类后得到了四类亮度像素，其中，第一类至第三类亮度像素的亮度滤波标识信息为开，第四类亮度像素的亮度滤波标识信息为关，也就是对第一类至第三类亮度像素进行滤波处理，对第四类亮度像素不进行滤波处理。对该图像中与亮度像素处于相同采样位置的色度像素(Cb或者Cr)与亮度像素分成同一类，也就是说将该图像中的与第一类至第四类亮度像素处于相同采样位置的色度像素分成第一类至第四类色度像素，最终得到的色度像素的分类结果如图11所示。由于第一类至第三类亮度像素均进行滤波处理，第四类亮度像素不进行滤波处理，因此，第一类至第三类色度像素(Cb或者Cr)也进行滤波处理，第四类色度像素不进行滤波处理。
在本申请实施例中，可以根据
Figure PCTCN2017077750-appb-000001
对图像的亮度像素进行分类，其中，C为亮度像素的最终分类号，D为亮度像素对应的图像区域的纹理方向性，
Figure PCTCN2017077750-appb-000002
为亮度像素对应的图像区域的变化强度。
其中，亮度像素对应的图像区域的纹理方向性D可以根据以下的步骤计算得到：
(1)、首先计算亮度像素对应的图像区域的水平方向的梯度gh、竖直方向的梯度gv，及两条对角线方向的梯度gd1，gd2如下：
Figure PCTCN2017077750-appb-000003
其中，Hk,l＝|2R(k,l)-R(k-1,l)-R(k+1,l)|；
Figure PCTCN2017077750-appb-000004
其中，Vk,l＝|2R(k,l)-R(k,l-1)-R(k,l+1)|；
Figure PCTCN2017077750-appb-000005
其中，D1k,l＝|2R(k,l)-R(k-1,l-1)-R(k+1,l+1)|；
Figure PCTCN2017077750-appb-000006
其中，D2k,l＝|2R(k,l)-R(k-1,l+1)-R(k+1,l-1)|；
其中，R(k,l)为亮度像素的预设位置的像素点的坐标，k为预设位置的像素点的横坐标，l为预设位置的像素点的纵坐标，R(k-1,l)，R(k+1,l)，R(k,l-1)，R(k,l+1)，R(k-1,l-1)，R(k+1,l+1)，R(k-1,l+1)，R(k+1,l-1)为预设位置的像素点R(k,l)八邻域的像素点，i，j，a，b均为整数，i-a≤k≤i+b，j-a≤l≤j+b。
(2)、计算水平方向和竖直方向梯度的最大值
Figure PCTCN2017077750-appb-000007
以及最小值
Figure PCTCN2017077750-appb-000008
Figure PCTCN2017077750-appb-000009
(3)、计算两条对角线方向梯度的最大值
Figure PCTCN2017077750-appb-000010
最小值
Figure PCTCN2017077750-appb-000011
Figure PCTCN2017077750-appb-000012
(4)、确定两个门限值t1，t2，对梯度的最大最小值进行如下比较，以确定方向性D：
1.如果
Figure PCTCN2017077750-appb-000013
且
Figure PCTCN2017077750-appb-000014
则D＝0；
2.如果
Figure PCTCN2017077750-appb-000015
则进入步骤3)，否则进入步骤4)
3.如果
Figure PCTCN2017077750-appb-000016
则D＝2，否则D＝1；
4.如果
Figure PCTCN2017077750-appb-000017
则D＝4，否则D＝3。
而亮度像素对应的图像区域的变化强度
Figure PCTCN2017077750-appb-000018
可以通过以下的方式计算得到：
(1)、计算亮度像素块对应的图像区域的变化强度A：
Figure PCTCN2017077750-appb-000019
(2)、A被进一步量化为[0,4]中的一个整数，量化的值被记做
Figure PCTCN2017077750-appb-000020
这样就可以根据
Figure PCTCN2017077750-appb-000021
对图像的亮度像素进行分类，根据该公式可以将图像的亮度像素分成25类，因此，可以有对应的25组自适应滤波器系数。
可选地，作为一个实施例，当图5的方法应用于解码器时，在根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数之前，图5的方法还包括：解析码流，获取亮度滤波器的滤波器系数。
应理解，这里的解码器是通过亮度滤波器的滤波器系数来确定色度滤波器的滤波器系数的，而不是通过码流来获取色度滤波器的滤波器系数。
可选地，作为一个实施例，当图5的方法应用于编码器时，图5的方法还包括对亮度滤波器的滤波器系数进行编码。
编码器在编码时只需要对亮度滤波器的滤波器系数进行编码，而不需要对色度滤波器的滤波器系数进行编码，节省了需要传输的码流。
上文结合图1至图11对本申请实施例的图像滤波方法进行了详细的介绍，下面将结合图12和图13对本申请实施例的图像滤波装置进行详细的介绍，应理解，图12和图13中的图像滤波装置能够实现上文中描述的图像滤波的方法的各个步骤，为了简洁，下面适当省略重复的描述。
图12是本申请实施例的图像滤波装置的示意性框图。图12的图像滤波装置1200可以执行上述图5中的图像滤波方法，该图像滤波装置1200包括：
确定模块1210，用于根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，所述亮度滤波器和所述色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，所述亮度滤波器的全部滤波器系数呈现第一几何分布，所述色度滤波器的全部滤波器系数呈现第二几何分布，所述第一几何分布和所述第二几何分布为相似图形，处于所述第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于所述第一几何分布边缘的亮度滤波器的滤波器系数计算得到；
滤波模块1220，用于采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进行所述滤波处理。
本申请中，色度滤波器的滤波器系数可以根据亮度滤波器的滤波器系数来确定，使得在传输码流时只需要传输亮度滤波器的滤波器系数对应的码流即可，能够节省传输的码流。
可选地，作为一个实施例，所述确定模块1210具体用于：根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器中的第三类滤波器系数；根据所述亮度滤波器中的第二类滤波器系数，确定所述色度滤波器中的第四类滤波器系数；其中，所述第四类滤波器系数为所述色度滤波器中处于所述第二几何分布边缘的滤波器系数，所述第三滤波器系数为所述色度滤波器中除所述第四类滤波器系数之外的滤波器系数，所述第一类滤波器系数为相对于所述第一几何分布的几何中心的位置与一个所述第三类滤波器系数相对于所述第二几何分布的几何中心的位置相同的滤波器系数，所述第二类滤波器系数为所述亮度滤波器中除所述第一类滤波器系数之外的滤波器系数。
可选地，作为一个实施例，所述确定模块1210具体用于：将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，其中，所述第一色度滤波器系数相对于所述第二几何分布的几何中心的位置与所述第一亮度滤波器系数相对于所述第一几何分布的几何中心的位置相同。
可选地，作为一个实施例，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括L20、L12、L19，所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，L19相对于L20的位置与C5相对于C6的位置相 同，所述确定模块1210具体用于：将L20、L12以及L19分别作为C6、C2和C5。
可选地，作为一个实施例，所述确定模块1210具体用于：将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，其中，所述第二色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第二亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
可选地，作为一个实施例，所述与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K的所述第二类滤波器系数，其中，K为大于等于1的整数。
可选地，作为一个实施例，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述确定模块1210具体用于：将L1、L2、L3、L0以及L6的和作为C0；将L4、L5、L10以及L11的和作为C1；将L7、L8、L13以及L14的和作为C3；将L9、L15、L16、L17以及L18的和作为C4。
可选地，作为一个实施例，所述确定模块1210还用于：确定所述亮度滤波器的抽头数目大于或者等于预设值。
可选地，作为一个实施例，所述确定模块1210具体用于：确定亮度滤波器的抽头数目；在所述亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
可选地，作为一个实施例，所述确定模块1210具体用于：将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第四色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
可选地，作为一个实施例，所述图像滤波装置1200还包括：
分类模块1230，用于对所述亮度像素进行分类，得到多个亮度像素类；
所述分类模块1230还用于对所述色度像素进行分类，得到多个色度像素类，其中，所述多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；
所述确定模块1210具体用于：确定所述亮度像素的亮度滤波标识信息，其中，所述亮度滤波标识信息用于指示对所述亮度像素和对应采样位置的色度像素进行所述滤波处理。
可选地，作为一个实施例，所述图像滤波装置1200应用于解码器，所述图像滤波装置1200还包括：
解码模块1240，用于解析码流，获取所述亮度滤波器的滤波器系数。
可选地，作为一个实施例，所述图像滤波装置1200应用于编码器，所述图像滤波装置1200还包括：
编码模块1250，用于对所述亮度滤波器的滤波器系数进行编码。
图13是本申请实施例的图像滤波装置的示意性框图。图13的图像滤波装置1300可以执行上述图5中的图像滤波方法，该图像滤波装置1300包括：
存储器1310，用于存储程序；
处理器1320，用于执行存储器1310中存储的程序，当该程序被执行时，处理器1320具体用于：根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，所述亮度滤波器和所述色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，所述亮度滤波器的全部滤波器系数呈现第一几何分布，所述色度滤波器的全部滤波器系数呈现第二几何分布，所述第一几何分布和所述第二几何分布为相似图形，处于所述第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于所述第一几何分布边缘的亮度滤波器的滤波器系数计算得到；采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进行所述滤波处理。
本申请中，色度滤波器的滤波器系数可以根据亮度滤波器的滤波器系数来确定，使得在传输码流时只需要传输亮度滤波器的滤波器系数对应的码流即可，能够节省传输的码流。
可选地，作为一个实施例，所述处理器1320具体用于：根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器中的第三类滤波器系数；根据所述亮度滤波器中的第二类滤波器系数，确定所述色度滤波器中的第四类滤波器系数；其中，所述第四类滤波器系数为所述色度滤波器中处于所述第二几何分布边缘的滤波器系数，所述第三滤波器系数为所述色度滤波器中除所述第四类滤波器系数之外的滤波器系数，所述第一类滤波器系数为相对于所述第一几何分布的几何中心的位置与一个所述第三类滤波器系数相对于所述第二几何分布的几何中心的位置相同的滤波器系数，所述第二类滤波器系数为所述亮度滤波器中除所述第一类滤波器系数之外的滤波器系数。
可选地，作为一个实施例，所述处理器1320具体用于：将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，其中，所述第一色度滤波器系数相对于所述第二几何分布的几何中心的位置与所述第一亮度滤波器系数相对于所述第一几何分布的几何中心的位置相同。
可选地，作为一个实施例，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括L20、L12、L19，所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述处理器1320具体用于：将L20、L12以及L19分别作为C6、C2和C5。
可选地，作为一个实施例，所述处理器1320具体用于：将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，其中，所述第二色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第二亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
可选地，作为一个实施例，所述与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K的所述第二类滤波器系数，其中，K为大于等于1的整数。
可选地，作为一个实施例，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述处理器1320具体用于：将L1、L2、L3、L0以及L6的和作为C0；将L4、L5、L10以及L11的和作为C1；将L7、L8、L13以及L14的和作为C3；将L9、L15、L16、L17以及L18的和作为C4。
可选地，作为一个实施例，所述处理器1320还用于：确定所述亮度滤波器的抽头数目大于或者等于预设值。
可选地，作为一个实施例，所述处理器1320具体用于：确定亮度滤波器的抽头数目；在所述亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
可选地，作为一个实施例，所述处理器1320具体用于：将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第四色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
可选地，作为一个实施例，所述处理器1320具体用于：对所述亮度像素进行分类，得到多个亮度像素类；对所述色度像素进行分类，得到多个色度像素类，其中，所述多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；确定所述亮度像素的亮度滤波标识信息，其中，所述亮度滤波标识信息用于指示对所述亮度像素和对应采样位置的色度像素进行所述滤波处理。
可选地，作为一个实施例，所述图像滤波装置1300应用于解码器，所述处理器1320还用于解析码流，获取所述亮度滤波器的滤波器系数。
可选地，作为一个实施例，所述图像滤波装置1300应用于编码器，所述处理器1320还用于对所述亮度滤波器的滤波器系数进行编码。
应理解，上述图像滤波装置1200和图像滤波装置1300可以具体位于编解码设备或者编解码器中，编解码设备或者编解码器也可以执行上文中描述的图像滤波方法。
下面结合图14至图16对编解码装置以及编解码装置组成的编解码系统进行详细的介绍。应理解，图14至图16中的编解码装置和编解码系统能够执行图5中的图像滤波方法。
图14和图15示出了本申请实施例的编解码装置50，该编解码装置50可以是无线通信系统的移动终端或者用户设备。应理解，本申请实施例可以在可能需要对视频图像进行编码和/或解码的任何电子设备或者装置内实施。
编解码装置50可以包括用于并入和保护设备的外壳30，显示器32(具体可以为液晶显示器)，小键盘34。编解码装置50可以包括麦克风36或者任何适当的音频输入，该音频输入可以是数字或者模拟信号输入。编解码装置50还可以包括如下音频输出设备，该音频输出设备在本申请的实施例中可以是以下各项中的任何一项：耳机38、扬声器或者模拟音频或者数字音频输出连接。编解码装置50也可以包括电池40，在本申请的其它实施例中，设备可以由任何适当的移动能量设备，比如太阳能电池、燃料电池或者时钟机构生成器供电。装置还可以包括用于与其它设备的近程视线通信的红外线端口42。在其它实施例中，编解码装置50还可以包括任何适当的近程通信解决方案，比如蓝牙无线连接或者USB/火线有线连接。
编解码装置50可以包括用于控制编解码装置50的控制器56或者处理器。控制器56可以连接到存储器58，该存储器在本申请的实施例中可以存储形式为图像的数据和音频的数据，和/或也可以存储用于在控制器56上实施的指令。控制器56还可以连接到适合于实现音频和/或视频数据的编码和解码或者由控制器56实现的辅助编码和解码的编码解码器54。
编解码装置50还可以包括用于提供用户信息并且适合于提供用于在网络认证和授权用户的认证信息的读卡器48和智能卡46，例如集成电路卡(Universal Integrated Circuit Card，UICC)和UICC读取器。
编解码装置50还可以包括无线电接口电路52，该无线电接口电路连接到控制器并且适合于生成例如用于与蜂窝通信网络、无线通信系统或者无线局域网通信的无线通信信号。编解码装置50还可以包括天线44，该天线连接到无线电接口电路52用于向其它(多个)装置发送在无线电接口电路52生成的射频信号并且用于从其它(多个)装置接收射频信号。
在本申请的一些实施例中，编解码装置50包括能够记录或者检测单帧的相机，编码解码器54或者控制器接收到这些单帧并对它们进行处理。在本申请的一些实施例中，编解码装置50可以在传输和/或存储之前从另一设备接收待处理的视频图像数据。在本申请的一些实施例中，编解码装置50可以通过无线或者有线连接接收图像用于编码/解码。
图16是本申请实施例的视频编解码系统10的示意性框图。如图16所示，视频编解码系统10包含源装置12及目的地装置14。源装置12产生经编码视频数据。因此，源装置12可被称作视频编码装置或视频编码设备。目的地装置14可解码由源装置12产生的经编码视频数据。因此，目的地装置14可被称作视频解码装置或视频解码设备。源装置12及目的地装置14可为视频编解码装置或视频编解码设备的实例。源装置12及目的地装置14可以包含台式计算机、移动计算装置、笔记本(例如，膝上型)计算机、平板计算机、机顶盒、智能电话等手持机、电视、相机、显示装置、数字媒体播放器、视频游戏控制台、车载计算机，或者其它类似的设备。
目的地装置14可经由信道16接收来自源装置12的编码后的视频数据。信道16可包括能够将经编码视频数据从源装置12移动到目的地装置14的一个或多个媒体及/或装置。在一个实例中，信道16可包括使源装置12能够实时地将编码后的视频数据直接发射到目的地装置14的一个或多个通信媒体。在此实例中，源装置12可根据通信标准(例如，无线通信协议)来调制编码后的视频数据，且可将调制后的视频数据发射到目的地装置14。所述一个或多个通信媒体可包含无线及/或有线通信媒体，例如射频(RF)频谱或一根或多根物理传输线。所述一个或多个通信媒体可形成基于包的网络(例如，局域网、广域网或全球网络(例如，因特网))的部分。所述一个或多个通信媒体可包含路由器、交换器、基站，或促进从源装置12到目的地装置14的通信的其它设备。
在另一实例中，信道16可包含存储由源装置12产生的编码后的视频数据的存储媒体。在此实例中，目的地装置14可经由磁盘存取或卡存取来存取存储媒体。存储媒体可包含多种本地存取式数据存储媒体，例如蓝光光盘、DVD、CD-ROM、快闪存储器，或用于存储经编码视频数据的其它合适数字存储媒体。
在另一实例中，信道16可包含文件服务器或存储由源装置12产生的编码后的视频数据的另一中间存储装置。在此实例中，目的地装置14可经由流式传输或下载来存取存储于文件服务器或其它中间存储装置处的编码后的视频数据。文件服务器可以是能够存储编码后的视频数据且将所述编码后的视频数据发射到目的地装置14的服务器类型。例如，文件服务器可以包含web服务器(例如，用于网站)、文件传送协议(FTP)服务器、网络附加存储(NAS)装置，及本地磁盘驱动器。
目的地装置14可经由标准数据连接(例如，因特网连接)来存取编码后的视频数据。数据连接的实例类型包含适合于存取存储于文件服务器上的编码后的视频数据的无线信道(例如，Wi-Fi连接)、有线连接(例如，DSL、缆线调制解调器等)，或两者的组合。编码后的视频数据从文件服务器的发射可为流式传输、下载传输或两者的组合。
本申请的编解码方法不限于无线应用场景，示例性的，可将所述编解码方法应用于支持以下应用等多种多媒体应用的视频编解码：空中电视广播、有线电视发射、卫星电视发射、流式传输视频发射(例如，经由因特网)、存储于数据存储媒体上的视频数据的编码、存储于数据存储媒体上的视频数据的解码，或其它应用。在一些实例中，视频编解码系统10可经配置以支持单向或双向视频发射，以支持例如视频流式传输、视频播放、视频广播及/或视频电话等应用。
在图16的实例中，源装置12包含视频源18、视频编码器20及输出接口22。在一些实例中，输出接口22可包含调制器/解调器(调制解调器)及/或发射器。视频源18可包含视频俘获装置(例如，视频相机)、含有先前俘获的视频数据的视频存档、用以从视频内容提供者接收视频数据的视频输入接口，及/或用于产生视频数据的计算机图形系统，或上述视频数据源的组合。
视频编码器20可编码来自视频源18的视频数据。在一些实例中，源装置12经由输出接口22将编码后的视频数据直接发射到目的地装置14。编码后的视频数据还可存储于存储媒体或文件服务器上以供目的地装置14稍后存取以用于解码及/或播放。
在图16的实例中，目的地装置14包含输入接口28、视频解码器30及显示装置32。在一些实例中，输入接口28包含接收器及/或调制解调器。输入接口28可经由信道16接收编码后的视频数据。显示装置32可与目的地装置14整合或可在目的地装置14外部。 一般来说，显示装置32显示解码后的视频数据。显示装置32可包括多种显示装置，例如液晶显示器(LCD)、等离子体显示器、有机发光二极管(OLED)显示器或其它类型的显示装置。
视频编码器20及视频解码器30可根据视频压缩标准(例如，高效率视频编解码H.265标准)而操作，且可遵照HEVC测试模型(HM)。H.265标准的文本描述ITU-TH.265(V3)(04/2015)于2015年4月29号发布，可从http://handle.itu.int/11.1002/1000/12455下载，所述文件的全部内容以引用的方式并入本文中。
在本申请所提供的实施方式中，应理解，“与A相应的B”表示B与A相关联，根据A可以确定B。但还应理解，根据A确定B并不意味着仅仅根据A确定B，还可以根据A和/或其它信息确定B。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应 涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (26)

  1. 一种图像滤波方法，其特征在于，包括：
    根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，所述亮度滤波器和所述色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，所述亮度滤波器的全部滤波器系数呈现第一几何分布，所述色度滤波器的全部滤波器系数呈现第二几何分布，所述第一几何分布和所述第二几何分布为相似图形，处于所述第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于所述第一几何分布边缘的亮度滤波器的滤波器系数计算得到；
    采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进行所述滤波处理。
  2. 如权利要求1所述方法，其特征在于，所述根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，包括：
    根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器中的第三类滤波器系数；
    根据所述亮度滤波器中的第二类滤波器系数，确定所述色度滤波器中的第四类滤波器系数；
    其中，所述第四类滤波器系数为所述色度滤波器中处于所述第二几何分布边缘的滤波器系数，所述第三滤波器系数为所述色度滤波器中除所述第四类滤波器系数之外的滤波器系数，所述第一类滤波器系数为相对于所述第一几何分布的几何中心的位置与一个所述第三类滤波器系数相对于所述第二几何分布的几何中心的位置相同的滤波器系数，所述第二类滤波器系数为所述亮度滤波器中除所述第一类滤波器系数之外的滤波器系数。
  3. 如权利要求2所述的方法，其特征在于，所述根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器系数中的第三类滤波器系数，包括：
    将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，其中，所述第一色度滤波器系数相对于所述第二几何分布的几何中心的位置与所述第一亮度滤波器系数相对于所述第一几何分布的几何中心的位置相同。
  4. 如权利要求3所述的方法，其特征在于，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括L20、L12、L19，所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，包括：
    将L20、L12以及L19分别作为C6、C2和C5。
  5. 如权利要求2所述的方法，其特征在于，根据所述亮度滤波器的第二类滤波器系 数，确定所述色度滤波器的第四类滤波器系数，包括：
    将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，其中，所述第二色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第二亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
  6. 如权利要求5所述的方法，其特征在于，所述与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：
    与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K的所述第二类滤波器系数，其中，K为大于等于1的整数。
  7. 如权利要求5或6所述的方法，其特征在于，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，包括：
    将L1、L2、L3、L0以及L6的和作为C0；
    将L4、L5、L10以及L11的和作为C1；
    将L7、L8、L13以及L14的和作为C3；
    将L9、L15、L16、L17以及L18的和作为C4。
  8. 如权利要求2-7中任一项所述的方法，其特征在于，所述方法还包括：
    确定所述亮度滤波器的抽头数目大于或者等于预设值。
  9. 如权利要求1所述方法，其特征在于，所述根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，包括：
    确定所述亮度滤波器的抽头数目；
    在所述亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
  10. 如权利要求9所述方法，其特征在于，所述将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数，包括：
    将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第六色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
  11. 如权利要求1-10中任一项所述的方法，其特征在于，在所述根据亮度滤波器的 滤波器系数，确定色度滤波器的滤波器系数之前，还包括：
    对所述亮度像素进行分类，得到多个亮度像素类；
    对所述色度像素进行分类，得到多个色度像素类，其中，所述多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；
    确定所述亮度像素的亮度滤波标识信息，其中，所述亮度滤波标识信息用于指示对所述亮度像素和对应采样位置的色度像素进行所述滤波处理。
  12. 如权利要求1-11中任一项所述的方法，其特征在于，所述方法应用于解码器，在根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数之前，还包括：
    解析码流，获取所述亮度滤波器的滤波器系数。
  13. 如权利要求1-11中任一项所述的方法，其特征在于，所述方法应用于编码器，所述方法还包括：
    对所述亮度滤波器的滤波器系数进行编码。
  14. 一种图像滤波装置，其特征在于，包括：
    确定模块，用于根据亮度滤波器的滤波器系数，确定色度滤波器的滤波器系数，其中，所述亮度滤波器和所述色度滤波器分别用于对待处理图像的亮度像素和色度像素进行滤波处理，所述亮度滤波器的全部滤波器系数呈现第一几何分布，所述色度滤波器的全部滤波器系数呈现第二几何分布，所述第一几何分布和所述第二几何分布为相似图形，处于所述第二几何分布边缘的色度滤波器的滤波器系数由一个或多个处于所述第一几何分布边缘的亮度滤波器的滤波器系数计算得到；
    滤波模块，用于采用所述亮度滤波器和所述色度滤波器分别对所述亮度像素和所述色度像素进行所述滤波处理。
  15. 如权利要求14所述装置，其特征在于，所述确定模块具体用于：
    根据所述亮度滤波器中的第一类滤波器系数，确定所述色度滤波器中的第三类滤波器系数；
    根据所述亮度滤波器中的第二类滤波器系数，确定所述色度滤波器中的第四类滤波器系数；
    其中，所述第四类滤波器系数为所述色度滤波器中处于所述第二几何分布边缘的滤波器系数，所述第三滤波器系数为所述色度滤波器中除所述第四类滤波器系数之外的滤波器系数，所述第一类滤波器系数为相对于所述第一几何分布的几何中心的位置与一个所述第三类滤波器系数相对于所述第二几何分布的几何中心的位置相同的滤波器系数，所述第二类滤波器系数为所述亮度滤波器中除所述第一类滤波器系数之外的滤波器系数。
  16. 如权利要求15所述的装置，其特征在于，所述确定模块具体用于：
    将所述第一类滤波器系数中的第一亮度滤波器系数的值赋予所述第三类滤波器系数中的第一色度滤波器系数，其中，所述第一色度滤波器系数相对于所述第二几何分布的几何中心的位置与所述第一亮度滤波器系数相对于所述第一几何分布的几何中心的位置相同。
  17. 如权利要求16所述的装置，其特征在于，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第一类滤波器系数包括L20、L12、L19， 所述第三类滤波器系数包括C6、C2、C5，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述确定模块具体用于：
    将L20、L12以及L19分别作为C6、C2和C5。
  18. 如权利要求15所述的装置，其特征在于，所述确定模块具体用于：
    将所述第二类滤波器系数中的第二亮度滤波器系数的值和与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数的值相加，作为所述第四类滤波器系数中的第二色度滤波器系数的值，其中，所述第二色度滤波器系数在所述第二几何分布中相对于几何中心的位置与所述第二亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
  19. 如权利要求18所述的装置，其特征在于，所述与所述第二亮度滤波器系数具有邻域关系的至少一个第三亮度滤波器系数，包括：
    与所述第二亮度滤波器系数在所述第一几何分布中相邻或间隔为K的所述第二类滤波器系数，其中，K为大于等于1的整数。
  20. 如权利要求18或19所述的装置，其特征在于，所述亮度滤波器为具有9×9菱形抽头的滤波器，所述色度滤波器为具有5×5菱形抽头的滤波器，所述第一几何分布为9×9菱形分布，所述第二几何分布为5×5菱形分布，所述第二类滤波器系数包括L0、L1、L2、L3、L4、L5、L6、L7、L8、L9、L10、L11、L13、L14、L15、L16、L17和L18，所述第四类滤波器系数包括C0、C1、C3和C4，其中，所述亮度滤波器的滤波器系数在所述9×9菱形分布中按照光栅扫描顺序依次为L0，L1，L2，L3，L4，L5，L6，L7，L8，L9，L10，L11，L12，L13，L14，L15，L16，L17，L18，L19，L20，L19，L18，L17，L16，L15，L14，L13，L12，L11，L10，L9，L8，L7，L6，L5，L4，L3，L2，L1，L0，所述色度滤波器的滤波器系数在所述5×5菱形分布中按照光栅扫描顺序依次为C0，C1，C2，C3，C4，C5，C6，C5，C4，C3，C2，C1，C0，所述确定模块具体用于：
    将L1、L2、L3、L0以及L6的和作为C0；
    将L4、L5、L10以及L11的和作为C1；
    将L7、L8、L13以及L14的和作为C3；
    将L9、L15、L16、L17以及L18的和作为C4。
  21. 如权利要求15-20中任一项所述的装置，其特征在于，所述确定模块还用于：
    确定所述亮度滤波器的抽头数目大于或者等于预设值。
  22. 如权利要求14所述装置，其特征在于，所述确定模块具体用于：
    确定所述亮度滤波器的抽头数目；
    在所述亮度滤波器的抽头数目小于预设值的情况下，将亮度滤波器的滤波器系数作为色度滤波器的色度滤波器系数。
  23. 如权利要求22所述装置，其特征在于，所述确定模块具体用于：
    将所述亮度滤波器中的第四亮度滤波器系数作为所述色度滤波器中的第四色度滤波器系数，其中，所述第四色度滤波器系数在所述第二几何分布中相对于几何中心的位置 与所述第四亮度滤波器系数在所述第一几何分布中相对于几何中心的位置相同。
  24. 如权利要求14-23中任一项所述的装置，其特征在于，所述装置还包括：
    分类模块，用于对所述亮度像素进行分类，得到多个亮度像素类；
    所述分类模块还用于对所述色度像素进行分类，得到多个色度像素类，其中，所述多个色度像素类中的任意一个色度像素类的分类与相同采样位置的亮度像素类的类别相同；
    所述确定模块具体用于：
    确定所述亮度像素的亮度滤波标识信息，其中，所述亮度滤波标识信息用于指示对所述亮度像素和对应采样位置的色度像素进行所述滤波处理。
  25. 如权利要求14-24中任一项所述的装置，其特征在于，所述装置应用于解码器，所述装置还包括：
    解码模块，用于解析码流，获取所述亮度滤波器的滤波器系数。
  26. 如权利要求14-24中任一项所述的装置，其特征在于，所述装置应用于编码器，所述装置还包括：
    编码模块，用于对所述亮度滤波器的滤波器系数进行编码。
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