Method and appropriate device for filtration of digital video images

FIELD: method for decreasing visual distortions in frame of digital video signal, which is encoded in blocks and then decoded.

SUBSTANCE: block type is determined in accumulator to encoding method for block, selected in accordance to given set of encoding type. For achieving technical result, i.e. decreasing visual distortions caused by limit of block, filtration is performed in the method, which is carried out depending on frame blocks types around the limit of block.

EFFECT: decreased visual distortions, increased reliability and efficiency.

9 cl, 6 dwg, 2 tbl

 

The present invention relates to a method of reducing visual distortion in the frame of the digital video signal, which encode blocks and then decode, and the type of blocks is determined in accordance with the encoding method for the block selected from a given set of encoding types, when this filter to reduce the visual distortion caused by the edge of the block. The present invention also concerns a device to reduce the visual distortion in the frame of the digital video signal, which is coded by blocks and then decoded, and the block type is determined in accordance with the encoding method for the block selected according to the predetermined set of encoding types, and the device includes a filter to reduce the visual distortion caused by the edge of the block. In addition, the present invention relates to a video encoder that contains a tool for encoding and decoding digital video signal blocks, and the block type is determined in accordance with the method of encoding a block selected according to the predetermined set of encoding types, and this encoder contains a filter to reduce the visual distortion caused by the edge of the block. The present invention also relates to decoder containing a means to reduce the visual distortion in the frame of the digital video signal, which is coded by blocks and then decoded, moreover, the block type is determined in accordance with the encoding method for the block selected according to the predetermined set of encoding types, and this video contains a filter to reduce the visual distortion caused by the edge of the block. The present invention also relates to the codec of the video signal containing the means for encoding and decoding digital video signal blocks, and the block type is determined in accordance with the method of encoding a block selected according to the predetermined set of encoding types, and this codec video contains a filter to reduce the visual distortion caused by the edge of the block. The present invention also relates to the rolling of the terminal that contains the video codec, which contains a means for encoding and decoding digital video signal blocks, and the block type is determined in accordance with the encoding method for the block selected according to the predetermined set of encoding types, and this codec video contains a filter to reduce the visual distortion caused by the edge of the block. The present invention additionally relates to a data carrier for storing auxiliary program that contains executable machine operation of encoding and decoding digital video signal blocks, and the block type is determined with regard to the availa able scientific C with the encoding method for the block, selected according to the predetermined set of encoding types, to reduce the visual distortion caused by the boundary block by filtering.

The relay system similar to those shown in figure 1, in General, is used to transmit digital video in compressed form. The video formed from consecutive frames. In some known systems, video transmission, for example, the systems, the relevant recommendations of the ITU-T H.261/H.263 (Committee for standardization as part of the ITU (International telecommunication Union)), identified at least three types of frames: I-frame (internal), P-frame (predicted or intermediate) and b-frame (bidirectional frame). An I-frame is formed exclusively on the basis of the information contained within the image, and on the receiving end of this I-frame can be used to form a full image. P-frames are formed on the basis of the preceding I-frame or P-frame, and at the stage of reception of the preceding I-frame or P-frame, respectively, used in conjunction with the received P-frame to restore the image. The layout of the P-frames, for example, to compress the amount of information using motion compensation. B-frames are formed on the basis of one or more previous P-frames or I-frames and/or one or more subsequent the x P - or I-frames.

Further, the frames are divided into blocks. One or more such blocks forming the block area. In General can be four different types of regions: the inner region of copying, coding region and not encoded region. The interior is a block area in which the blocks are encoded independently, without reference to any other frame. The copy area is composed of blocks that are obtained by copying the contents of the reference frame exactly at the same location without any prediction with motion compensation. Encoded region consists of blocks that are obtained by coding the prediction with motion compensation and prediction errors. The prediction error is the difference between the values of pixels (picture elements) of the actual frame and reconstructed frame, which is formed in the system encoding/decoding using prediction with motion compensation, as will be described in more detail in the following text. The forecast error code and sent to the receiving device. Not encrypted area get by using only prediction with motion compensation. Not actually encoded region is equivalent to the copy area, if the information of motion equals the I 0. All block area of one frame does not necessarily have the same types, but one frame can contain block region, which belong to different types.

Consider figure 1, which illustrates a typical system for encoding and decoding (codec)used, for example, when transmitting a digital video signal, thus encode the current frame of video arrives in the transmitting system 10 in the form of input data In(x,y). Input In(x,y) usually take the form of information of pixel values. In differential adder 11 is converted to the frame En(x,y) is the prediction error by subtracting from it the predicted frame Pn(x,y)formed on the basis of the previous image. The frame of the prediction error encoding unit 12 as described below, and the encoded frame, the prediction error is sent to the multiplexer 13. To generate a new predicted frame coded frame of the prediction error is also sent to the decoder 14, which forms the decoded framethe prediction error, which is summed in the adder 15 with the predicted frame Pn(x,y), forming in the decoded frame. The decoded frame store in the memory 16 frames. To encode the next frame, save the United in memory 16 frames, the frame read as a reference frame Rn(x,y), and convert to the new predicted frame Pn(x,y) in block 17 compensation and motion prediction according to the formula:

A pair of numbers [Dx(x,y), Dy(x,y)] is called the motion vector of the pixel at location (x,y), and Dx(x,y) and Dy(x,y) are the horizontal and vertical shifts of the pixel. They are calculated in block 18 of the motion estimation. The set of motion vectors [Dx(·), Dy(·)]consisting of all motion vectors associated with pixels to be compressed frame, also coded using motion models containing the basis functions and coefficients. The basic functions are known to both the encoder and the decoder. The values of the coefficients encode and sent to the multiplexer 13 multiplexes them into the same data stream with the encoded frame prediction errors for the parcel in the receiving device. Thus, the number of transferable information is greatly reduced.

Some frames may be partially, or fully, so difficult to predict that when coding is almost never used prediction with motion compensation. These frames or parts of frames to encode using the internal coding without prediction, and so there is no need to send in the receiving device to the contest is the Yuexiu information about the motion vector.

In the system 20 of the receiver demultiplexer 21 separates the encoded frames of the prediction error and the motion passed motion vectors, and sends the encoded frames of the prediction error in the decoder 22. The decoder 22 generates the decoded frame prediction errorswhich is summed by the adder 23 with the predicted frame Pn(x,y)formed on the basis of the previous frame, resulting in a decoded frame. The decoded frame is sent to the output 24 of the decoder and at the same time retain in memory 25 frames. When decoding the next frame stored in the frame memory frame read as a reference frame, and transform into a new predicted frame in the block 26 compensation and motion prediction in accordance with the above formula (1).

The encoding method used in block 12 for encoding a frame of the prediction error or the internal encoding of the frame or part of a P-frame to be making no predictions, in General, based on the transformation, more acceptable which is a discrete cosine transform, DCT. The frame is divided into contiguous blocks that have a size of, for example, 8×8 pixels. When encoding and decoding blocks are treated independently of the other. Transform count for the block to be coded, with the receipt of several members. The coefficients of these members quantuum in a discrete scale, so that they can be processed in digital form. Quantization causes the rounding errors, which can become visible in the image/ restored from blocks, so as to form a gap in the values of the pixels at the boundary between two adjacent blocks. Because some of the decoded frame is used to calculate a predicted frame for the subsequent predicted frames, these errors can be spread in successive frames, thus causing the formation of visible edges in the image being played receiver. Distortion of this type are called blocking distortions (artifacts).

Some common ways to remove blocking artifacts. These methods are distinguished by the following features:

by definition, for any pixel/pixels required correction values, to avoid blocking distortion

- determining the appropriate filtering "lower frequency" for each subject to adjustment pixel based on the values of other pixels, divided by the bandwidth of the filter, located around the pixel

- calculation of a new value the I pixel, subject to correction, and

- new rounding values to the nearest digital value of a pixel.

Factors influencing the choice of the filter and the decision whether to use filtering may constitute, for example, the difference between the values of the pixels across the boundary of the block, the step size of the quantization coefficients obtained by the transformation, and the difference of pixel values on different sides of the processed pixel.

It has been found that the known methods have a tendency to delete lines that belong to the real characteristics of the image. On the other hand, the known methods are not always capable of removing all blocking distortion.

The present invention is to provide a new type of device filter to reduce blocking distortion. The invention also has the task, namely, to a method and an associated device worked more reliably and efficiently than known solutions.

The method according to the invention adjusts the filter parameters in accordance with the type of blocks, the boundary of which is subject to filtering. Various filtering options are selected in accordance with the type of blocks on both sides of the border, to ensure the superior of the filter.

Objectives of the invention are solved by adapting the selection of pixels for Phi is Tracie and filtering process, more flexible than before, with respect to the features of the frame and environment point filtering, and by taking into account the nature/type of units that are subject to filtering.

According to the first aspect of the invention, a method for reducing visual distortion in the frame, which encode blocks, characterized in that the filtering is performed on the border of the block depends on the block type frame in the vicinity of the block boundaries.

According to the second aspect of the invention, the proposed device for implementing the method corresponding to the invention. The device according to the invention is characterized in that the filter is made with the possibility of adaptive functioning in accordance with the block type frame around the border of the block.

According to a third aspect of the invention, the proposed encoder, characterized in that the filter is made with the possibility of adaptive functioning in accordance with the block type frame around the border of the block.

According to a fourth aspect of the invention, a decoder, characterized in that the filter is made with the possibility of adaptive functioning in accordance with the block type frame around the border of the block.

According to the fifth aspect of the invention, the proposed codec, characterized in that the filter is made with the possibility of adaptive functioning according the types of blocks of the frame around the border of the block.

According to the sixth aspect of the invention, a mobile terminal, characterized in that the filter is made with the possibility of adaptive functioning in accordance with the block type frame around the border of the block.

According to the seventh aspect of the invention, a data carrier, characterized in that the auxiliary program further comprises executable machine operation for the adaptive filter corresponding to the block type frame around the border of the block.

Since the blocking distortion appear only at block boundaries according to the invention, filtering is mostly applied only to the pixels at block boundaries close to them. Edges that are part of the image that may reside anywhere in the image area. In order for corrective filter was chosen only pixels containing blocking distortion, and that the quality of the edges that are part of a directly picture, there was no effect during filtration, made the following assumptions.

Changes of pixel values associated with the edges that are part of the image, in General, more than the changes associated with the blocking distortion, and those edges within the image, where the pixel is small, do not suffer significantly from what krupenia difference values of the pixels, due to the filtering.

Because subject to encoding the image in General is divided into blocks in the vertical and in the horizontal direction, the image contains both vertical and horizontal block boundaries. As for the vertical block boundaries, there are pixels to the right and to the left of the border, as for the horizontal block boundaries, there are pixels above and below the boundary. In General, the location of the pixels can be described as being on the first or second side of the border block. In an exemplary embodiment, the filtering method according to the invention the number of pixels to be adjusted, the characteristic features of the filter used and the size of the bandwidth of the filter depends on the following factors:

a) type blocks on both sides of the border (for example, intermediate, copy, encoded, not encrypted),

b) the difference of the values Δ pixels across the boundary of blocks. The difference can be defined in several ways. One definition is Δ=|r1-l1|, where r1- the value of the pixel on the first side boundary of the block nearest to the border, a l1- the value of the pixel on the second side of the border of the block nearest to the border,

c) step size QP quantization coefficients obtained are used in the encoding is converted into the adowanie, and

d) differences of pixel values between pixels on the first side boundary of the block and, respectively, between the pixels on the second side of the border block.

In an advantageous embodiment of the method according to the invention, the number selected for filtering pixels can be changed, and it need not be the same on different sides of the border block. The number of pixels also depends on the type of blocks on both sides of the border. Since the number of pixels to fit the General features of the graphic information contained in the frame in a specific area, in accordance with the above-mentioned factors, the method provides the best filtering results than known methods. The "best" result in this context is the result, in which block distortion is reduced to a greater extent, while on the real edges in the image are exposed to a lesser degree. This means that the more the number of block distortion can be removed without undue weakening of the edges of the actual image.

It should be noted that in other embodiments of the invention the factors affecting performed on the boundary of block filtering may differ from the factors listed above.

Further the invention will be described more in detail about the wearing of the preferred embodiments and the accompanying drawings, which

figure 1 is a system for encoding and decoding (codec) digital video, known from the prior art,

figure 2 represents the location of the pixel relative to the boundaries of the block in an exemplary embodiment of the method according to the invention,

figure 3 represents an alternative solution to perform the filtering method according to the invention in the system of encoding and decoding digital video,

figure 4 depicts a schematic representation of a device for implementing the method according to the invention,

figure 5 represents the device according to figure 4 in action, and

6 depicts a schematic representation of a portable device video that implements the method according to the invention.

In the above description in connection with the description of the prior art, reference is made to figure 1. In the following description of the invention and its preferred embodiments reference will be made mainly in Fig.2-5. In the drawings the same reference position are used to indicate corresponding parts.

Figure 2 depicts the location of the pixels r1-r6and l1-l6relative to the vertical boundary 30 of the block. For implementing the method according to the invention define some parameters. The parameter n represents the biggest to the number of eligible study of pixels from the border of the block in one direction, in the case of figure 2, this value is 6. It is advisable to choose a value n so that it had some relationship to the difference of the values Δ pixels across the boundary of the block, and the step size QP quantization coefficients obtained by the image encoding. In addition, the value of the parameter n is predominantly less than or equal to the number of pixels in the block in the direction of the study, to avoid the possibility of blocking distortion associated with the boundaries of the previous block, extending to the border of the block. For use in the preferred embodiment of the invention applied to image blocks containing 8x8 pixels, it is recommended that the following definition:

where α=QP·log(QP). If QP has a different value on different sides of the boundary block, the calculation uses the smaller value of QP, as well as in all following cases, in which the definition contains a reference to exactly one value QP. The invention does not impose any restrictions on the parameter value definition n, but according to the expression (2), mostly it is in General above, when the difference Δ values of pixels across the boundary of the block is small compared to the step size QP quantization coefficients, recip is the R in the transform coding. If the difference between the values Δ pixels large, there is a high probability that the boundary of the block has a valid edge of an image, and in this case, the pixels preferably not investigate for filtering (n=0).

In the next operation of the filtering method according to the invention will explore information about the type of area relative to the two adjacent blocks, that is, consider the type of blocks on both sides of the investigated boundary of the block. According to the information about the type of the field value of the parameter n can be further restricted (reduced)to provide even better results to reduce blocking distortion. Information about the type of the field is included, for example, coded information relating to the pixels of the specific block, where this information is contained, or is temporarily stored during decoding block until the specified short value of nabbrfor the parameter n.

Table 1 shows reduced values in accordance with the preferred embodiment of the present invention. Table 1 is applicable in the situation when the maximum value of n is 6, and, of course, in situations where the maximum value differs from 6, may also be appropriate for other shorter values. Shorter values are used for the first and second sides of the border block in the head of the dependence on the type of field unit on the first side boundary of the unit and the type of field unit on the second side of the border block.

Table 1
The block type at the second side of the border
Unit type on the first side of the borderINTERNALCOPYCODEDNECTARIVORY
INTERNALnn22n4n2
COPY22222422
CODED4n424442
NECTARIVORY2n222422

Each cell in the table 1, corresponding to a specific combination of types of areas, divided into two parts. The value on the left gives an abbreviated value (Sz) to the first side of the edge block, and the value on the right gives the abbreviated value of Sz for the second side of the border. If the value of the parameter n exceeds the value on the TES in table 1, n is reduced to a reduced value Sz, are shown in table 1. However, if the full value of the parameter n does not exceed the value given in table 1, the value of the parameter n (originally defined by the expression (2)) is stored. In table 1, the symbol "n" indicates that an additional reduction is not performed, and the parameter value is stored. Reduced the value of nabbrfor the parameter n can also be represented by the formula:

The same table can be used for filtering across the vertical block boundaries (horizontal filtering), through the introduction of "Left/Right" instead of "First/Second", and to filter through the horizontal block boundaries (vertical filtering), through the introduction of "lower/Upper" instead of "First/Second", respectively. Now the value on the left gives an abbreviated value for pixels from the left/lower boundaries of the unit, and the value to the right gives an abbreviated value for pixels on the left/top border.

To further clarify the use of table 1 further shows an estimate of the situation. In this illustrative exemplary situation "horizontal filtering is performed during the vertical boundary 30 of the block. Assuming that the value for n is calculated from equation 2, costall the em for example, 4, the block on the left side of the border 30 of the block has an internal type, and the block on the right side of the border in question 30 of the block is not coded type, table 1 indicates that the abbreviated value for the left side is n, and the reduced value for the right side is equal to 2. This means that 4 pixels are selected, next to the border of the block (= estimated value n), for research on the left side of the border, and are 2 pixel closest to the boundary of the block (= reduced value of n), for research on the right side.

Below is another example situation. In this illustrative exemplary situation "horizontal filtering is performed through a vertical border 30 of the block. Assuming that the value of the parameter n, is calculated from equation (2)is, for example, 4, and blocks on both sides of the border in question 30 of the block have the backup type, table 1 indicates that the abbreviated value for the left side is equal to 2, and an abbreviated value for the right side is equal to 2. This means that 2 pixels are selected, next to the border of the block (= reduced value of n), for research on the left side of the border, and are 2 pixel closest to the boundary of the block (= reduced value of n), for research on the right side.

For danaperino predicted frames (B-frames) with the treatment parameter n is not advisable to apply, since there is no clearly-defined type information blocks.

The next operation in the filtering method according to the invention consists in determining the values of parameters dland drthat represent the activity, or the difference of pixel values between pixels on one side of the border block. The preferred definition for dris as follows:

dr=6, ifwith all j ∈ [1, 6],

otherwise: dr=i, where i satisfies the conditions

with all j ∈ [1, i].

Here is the auxiliary parameter β=4·log(QP). The value of the parameter dlis defined similarly, except that all the symbols r are replaced by the symbols 1, and the parameter n should be appropriate reduced value of nabbr. In the definition (4) there is a number 6, because, according to equation (2), the highest possible value of n in this case is 6. If n is defined differently, but the parameters drand dlare defined according to definition (4), the number 6 should be replaced by the highest possible value of n in accordance with the new definition.

Parameter values drand dlmainly count on receiving yaytsa independently from each other, since the graphical information contained in the frame, may be different on different sides of the border block. The invention does not limit the definition of the parameters drand dlbut according to the definition (4) these parameters are primarily used to limit the blocking distortion by processing relatively close to the border of the block, if near the border of the block has a valid edge of an image. In the end, you can get significant features definitions (4) in the following way: the value of the parameter dr(and, accordingly, the value of dl) provides an indication as to how many pixels counted from the boundary of the block, have approximately the same value as the pixel at the border of the block.

The high value of the parameter n (e.g., 6) indicates that the difference between the pixel values at the boundary of the block is relatively small compared with the total change of pixel values within a block. In this case, it is possible that near the border of the block has a valid edge of an image. Choosing a relatively small value of the parameter dr(or dl), you can limit the filtering aimed at correcting the blocking distortion, so that she had no detrimental impact on the edge of the actual image is close to the border of the block In some situations, a large number of pixels, it is estimated from the border of the block has approximately the same value as the pixel at the border of the block. In this case, the definition (4) gives the parameter dr(or dlwith a relatively high value. However, if there is a clear gap in pixel values between blocks, the parameter n has a small value, and in the definition (4) is reduced the value of nabbrthat ensures that it will not be selected such unreasonably high value as the value of parameter dr(or dl). Otherwise, the relatively high value of the parameter dr(or dlwill lead to unnecessary filtering.

If the blocks on both sides of the border of the block are blocks of the internal type, the reduction does not affect the selection of the values of the parameters n, drand dl. On the other hand, if at least one of the blocks has a type that is different from the interior, reducing the value of n according to the formula (3) may limit the number of filtered pixels. This has the advantage that the boundaries of the block are not anti-aliased too much.

In addition, you should decide on the largest possible number of pixels to be filtered. It does not have its own designation in figure 2, but may be, for example, 3 and this means that the filter can only be used for the corre is the pit of the pixel values of r 1, r2, r3, l1, l2and l3.

When the values of the parameters n, nabbrdrand dldefined, it is filtered through the use of a suitable filter. The invention does not limit the type of filter that you can use, but the following describes a filter device which is found preferable. Filtering is used to determine new values for the pixels selected for filtering. In a preferred embodiment of the invention for a given pixel is determined by the new pixel value by computing an average value of pixel values that appear in the passband of the filter. In a preferred embodiment, the bandwidth of the filter is symmetrical relative to the subject to filter pixel and contains, in addition to subject the filter to the pixel, one, two or three pixels from both sides, depending on parameter values drand dlas described below. Of course, these are just examples, and you can choose other values in situations where n, nabbrdrand dlare defined differently. The calculated average value is rounded up to the nearest digital value of a pixel, whereby it becomes the new value of the filtered pixel.

Table 2 shows the definition of the Shire who have bandwidth filtering for pixels of r 1, r2and r3in accordance with the value of the drin a preferred embodiment of the invention. The pixel values of l1, l2and l3are defined in the same way in accordance with the value of the dl. In the table the symbol "X" means that the pixel is not filtered at all, and the number means that the bandwidth of the filter contains the number of pixels shown by this number, on each side of the examined pixel. In addition, table 2 shows that for the filter you want to apply to any pixel, both the drand dlmust have a value greater than 1.

dr(dl>1)r1r2r3
1XXX
21XX
311*X
422X
5222**
63 or 2***33

* Filtered pixel value r1is used to filter the pixel r2

** The filtered pixel values of r1and r2used for filtering the pixel r3

*** 3 if dl>2, otherwise 2.

The above description relates to filter on one horizontal line of pixels, which has a length of 12 pixels and located symmetrically on both sides of the vertical boundaries of the unit. Description easy to generalize about the vertical parts of columns of pixels, which are located symmetrically on both sides of the horizontal boundaries of the unit: Fig. 2 can be rotated 90 degrees counterclockwise, whereby the boundary 30 of the block is horizontal, and the pixels shown in the drawing, forming a part of the vertical column of pixels so that the pixels r1-r6become pixels upstream boundary and the pixels of the l1-l6- pixels located below the boundary. To filter the boundaries of the block across the frame, applying the method according to the invention, all vertical boundaries of the unit frame are subjected to study line by line, and all of the horizontal block boundaries are investigated column after column. The procedure is essentially irrelevant, and thus, need to be investigated all the horizontal boundaries of the blocks of the frame column after column, and then all vertical the borders of the block line by line. In an advantageous embodiment of the invention, the filtering is repeated line by line, i.e. the first filtered first row of pixels in blocks (beyond the boundaries), then the second line and so on

Figure 3 depicts, in any known points system for encoding and decoding (codec) digital image can be improved by applying a filter according to the invention. The first alternative is the placement of the unit carrying out the filtering method according to the invention, at the output of the decoder of the receiver, as illustrated reference position 31. In this case, the boundaries of the block in the frame image is filtered after decoding all blocks within the frame. This requires information about the type of blocks is maintained for all blocks in one frame. Another alternative is to place the filtration unit in the receiving device before the point at which the decoded frame is sent to the memory 25 frames for forming a predicted frame, as illustrated reference position 32. In this case, the type information block for all blocks within a frame must remain as filtering the boundaries of the unit is still running after decoding and recovery of the full frame. However, this alternative has the advantage that sanlucas is to be in the removal of the blocking distortion also affects the formation of the predicted frame, whereby the blocking distortion in one frame do not extend through the predicted frame to the subsequent frames. To achieve the described effect of the block, which performs filtering according to the invention, can be placed either before or after the memory 25 frames. However, the preferred location is denoted by the reference position 32, as when filtering is applied at this stage, it affects both the frame subject to removal by the decoder of the receiving device and the frame to be saved in memory. In the transmitting unit, carrying out the filtering method according to the invention, can be placed, as depicted by reference positions 33 and 34, either before or after the memory 16 frames. Thus, the invention can also be used to create a corrected predicted frame at the transmitting end.

In a particularly preferred variant of the invention, the block that performs filtering according to the invention, implemented in a digital signal processor or similar device suitable for digital signal processing, which can be programmed to apply a predetermined processing to the signal received is as input. 4 shows a functional block elements, performing the filtering method according to the invention, implemented in the form of a digital signal processor. Accordingly, the operation of the filtration unit is illustrated in figure 5. First, consider figure 4, where the functional elements are programmed with the functional definitions (35-39) to calculate the parameters that control the filtering method according to the invention. Mainly that the functional definitions are loaded into the signal processor in connection with its manufacture or programming. During operation according to figure 5, the frame is temporarily stored in the register 41 so that it can be processed by the signal processor. The frame processing continues from block to block. At the moment the number of pixels indicated by the parameter n, nabbraccording to the definitions provided in table 1, is selected for the study 42 on each side from a point on a boundary of the block is calculated d-options 43 and filter 44. These operations are repeated until such time as all boundaries of all blocks will not be filtered/processed, after which the frame can be output from the register 41, and save a new frame for processing. In accordance with figure 4 and 5 can perform activities in a separate signal processor, or they can be realizowany in a General processor, which also includes other devices for signal processing.

You can use a storage medium for storing program software that contains executable machine operation for implementing the method according to the invention. In an advantageous embodiment of the invention, the software program is read from the data medium in the device containing programmable means, such as a processor, for performing the method according to the invention.

The invention can be modified, without departing from the scope of the claims defined below by the claims, using the capabilities of a person skilled in the art without the use of actual inventive steps. For example, the parameter Δ can be calculated by using the formula Δ=|(r1+r2)-(l1+l2)| or some considered appropriate to another formula. The determination of other parameters presented above should be considered only as examples. Particularly advantageous use of the invention lies in the applications of portable video devices, digital television receivers and other devices that are at least receive and decode digital video. Further it should be noted that the method according to the invention in General is to emanate to any method of coding images, in which the image is encoded/decoded from block to block, including individual (i.e., fixed) digital images.

6 depicts a mobile terminal 46, intended for use as a portable device video sharing and application of the method according to the invention. The mobile terminal 46 mainly contains at least means 47 display to display images, audio means 48 for capturing and playback of audio information, 49 keyboard for input, for example, user commands, part 50, radio communication equipment for communication with the mobile communications network (not shown), the tool 51 processing to control the operation of the device, the tool 52 memory for storing information and preferably a camera 53 for making images.

The present invention is not limited solely to the above embodiment, but may be modified within the scope of the attached claims.

1. The way to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, wherein performing the filtering operation on the pixel values at the block border or close to it and adjust at least one parameter filtering operation based, at least in part from the way the code is testing, used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

2. The method according to claim 1, characterized in that the frame contains at least one region of image blocks and a filtering operation performed on the pixel values at the block border or close to it, depends at least partly on the type of field unit of the image on the first side of the border blocks and region type of the block image on the second side of the border blocks.

3. The method according to claim 1, wherein adjusting at least one parameter filtering operations are performed on the pixel values, at least on one side of the border blocks depending on the encoding method used to encode the at least one block of the image in the vicinity of the block boundaries.

4. The method according to claim 3, wherein adjusting at least one parameter filtering operations are performed on the pixel values at the block border or close to it depending on the encoding method used to encode the first block of the image, and the second unit image, and the first and second image blocks located on opposite sides of the verge of the s blocks.

5. The method according to claim 3 or 4, characterized in that the said at least one parameter is one of the following: the number to be study of pixels, the number of filtered pixels, degree of activity, which provides an indication of the difference between pixel values on one side of the block boundaries, the bandwidth of the filter.

6. The method according to claim 1, wherein the chosen number of pixels (n) for research, at least one side of the border blocks.

7. The method according to claim 6, characterized in that the number of pixels (n)selected for study will depend on the difference (Δ) in pixel value between pixels across the boundary of blocks.

8. The method according to claim 6 or 7, characterized in that the number of pixels selected for study depends on the size of the quantization step used for quantization of the coefficients used in the coding blocks of the image.

9. The method according to claim 8, characterized in that the number of pixels (n), selected for the study is determined by the formula

where Δ - the difference between the values of the pixels across the boundary of blocks, α=QP·log(QP), QP is the size of the quantization step used for quantization of the coefficients used in the coding blocks of the image.

10. The method according to claim 6, great for the decomposing those first determine the number of pixels (n), selected for the study, in accordance with the contents of the image frame in the vicinity of the block boundaries, and then reduce depending on the encoding method used to encode the block image in the vicinity of the block boundaries, to give a reduced number of pixels (nabbrfor the study.

11. The method according to claim 10, characterized in that a reduced number of pixels (nabbrdetermined by the choice of a reduced value (Sz) in accordance with table

The type area of the block on the other side of the border
Type of field unit on the first side of the borderINTERNALCOPYENCODEDNEKODIROVANNIE
INTERNALnn22n4n2
COPY22222422
ENCODED4n42 4442
NEKODIROVANNIE2n222422

and use of the selected reduced values (NW) using the formula

12. The method according to claim 1, characterized in that select some pixels to be filtered, and for each subject filtering of the pixel define a new value based on the pixels that appear in the passband of the filter, defined around the pixel.

13. The method according to claim 6, wherein to filter the pixels selected from the pixels selected for study.

14. The method according to item 12, wherein determine a new value to be filtered pixel by calculating the average value of pixels that appear in the passband of the filter.

15. The method according to item 12, characterized in that the size of the bandwidth of the filter are determined according to table

dr(dl>1)r1r2r3
1XXX
21 XX
311*X
422X
5222**
6(3 or 2)***33

where

* means that the filtered pixel value r1used for filtering pixel r2;

** means that the filtered pixel values of r1and r2used for filtering pixel r3;

*** means 3, if dl>2, otherwise 2,

moreover, the integer parameter drrepresents the degree of

activity, which indicates activity on the first side of the block boundaries, and an integer parameter dlrepresents the degree of activity, which indicates activity on the second side of the block boundaries, r1, r2and r3represent the three pixel on the first side of the block borders, next to the border in this order, X means that the pixel is not filtered, the number of means in addition to subject the filter to a pixel bandwidth of the filter on both sides of the subject to filter the pixel take the number of pixels shown by this number, and the expression "3 or 2" means "3 if dl/sub> >2, otherwise 2", and to determine the new values of the filtered pixels on the other side of the border blocks use the bandwidth of the filter, defined similarly, except that all characters r replace characters 1 and Vice versa.

16. The method according to item 15, characterized in that the said activity is determined on the basis of changes in the pixel values.

17. The method according to item 15 or 16, characterized in that

dr=6, ifwith all j ∈ [1, 6],

otherwise: dr=i, where i satisfies the conditions

,

with all j ∈ [1, i]

where is the auxiliary parameter β=4·log(QP), a QP is the size of the quantization step used for quantization of the coefficients used in the coding of image blocks, nabbr- reduced number of pixels, and the value of the parameter dldetermined similarly, except that all characters of g is replaced by the symbol 1.

18. Filter to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, characterized in that it is made to perform a filtering operation on the value is x pixels in the block border or close to it, and correction, at least one set of parameter filtering operations based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

19. Filter by p, characterized in that the frame contains at least one region of image blocks, and the filter is made to perform a filtering operation on the pixel values at the block border or close to it, depending, at least in part on the type of the block image on the first side of the border blocks and region type of the block image on the second side of the border blocks.

20. Filter by p, characterized in that it is configured to correct at least one predetermined parameter of the filtering operation performed on the pixel values, at least on one side of the border blocks depending on the encoding method used to encode the at least one block of the image in the vicinity of the block boundaries.

21. The filter according to claim 20, characterized in that it is configured to correct at least one predetermined parameter of the filtering operation performed on the pixel values at the block border or close to not is depending on the encoding method, used to encode the first block of the image, and the second unit image, and the first and second image blocks located on opposite sides of the block boundaries.

22. The filter according to claim 20 or 21, characterized in that the said at least one parameter is one of the following: the number to be study of pixels, the number of filtered pixels, degree of activity, which provides an indication of the difference between pixel values on one side of the block boundaries, the bandwidth of the filter.

23. Filter by p, characterized in that the selectable number of pixels (n) for research, at least one side of the border blocks.

24. The filter according to item 23, characterized in that the selectable number of pixels (n) for research depending on the difference (Δ) in pixel value between pixels across the boundary of blocks.

25. The filter according to item 23 or 24, characterized in that the selectable number of pixels for research depending on the size of the quantization step used for quantization of the coefficients used in the coding blocks of the image.

26. Filter by A.25, characterized in that the number of pixels (n), selected for the study are defined according to the formula

where Δ - the difference between the values of the pixels across the boundary of blocks, α=QP·log(QP), QP is the size of the quantization step used for quantization of the coefficients used in the coding blocks of the image.

27. The filter according to item 23, characterized in that made with the possibility of reducing the number of pixels (n), selected for study, depending on the encoding method used to encode the block image in the vicinity of the block boundaries, to give a reduced number of pixels (nabbrfor the study.

28. Filter by item 27, characterized in that made with the possibility of reducing the number of pixels (n), selected for study by selecting a reduced value (Sz) in accordance with table

The block type at the second side of the border
Unit type on the first side of the borderINTERNALCOPYCODEDEITHER
INTERNALnn22n4n2
The COPIER IS FOR 22222422
CODED4n424442
EITHER2n222422

and use of the selected reduced values (NW) using the formula

29. Filter by p, characterized in that it is made with a choice of some pixels, filtered, and determining a new value for each subject filtering pixel based on the pixels that appear in the passband of the filter, defined around the pixel.

30. Filter by clause 29, characterized in that it is arranged to determine the new value to be filtered pixel by calculating the average value of pixels that appear in the passband of the filter.

31. Filter by clause 29, characterized in that it is arranged to determine the size of the bandwidth of the filter in accordance with table

dr( l>1)r1r2r3
1XXX
21XX
311*X
422X
5222**
6(3 or 2)***33

where * means that the filtered pixel value r1used for filtering pixel r2,

** means that the filtered pixel values of r1and r2used for filtering pixel r3,

*** means 3, if dl>2, otherwise 2,

and with the integer parameter drrepresents the degree of activity, which indicates activity on the first side of the block boundaries, and an integer parameter dlrepresents the degree of activity, which indicates activity on the second side of the block boundaries, r1, r2and r3represent the three pixel on the first side of the block borders, next to the border in this order, X means that the pixel is not filtered, the number of means in addition to subject the filter to the pixel leprosy bandwidth filtering on both sides of the subject to filter the pixel is taken as the number of pixels it is shown that number, and the expression "3 or 2" means "3 if dl>2, otherwise 2", and to determine the new values of the filtered pixels on the other side of the border blocks are executed with use of the bandwidth of the filter, defined similarly, except that all characters of g is replaced by the symbols l and Vice versa.

32. Filter by p, characterized in that

dr=6, ifwith all j ∈ [1, 6],

otherwise dr=i, where i satisfies the conditions

with all j ∈ [1, i]

where is the auxiliary parameter β=4·log(QP), a QP is the size of the quantization step used for quantization of the coefficients used in the coding of image blocks, nabbr- reduced number of pixels, and the value of dldefined similarly, except that all characters of g is replaced by the symbol l.

33. Video encoder contains a filter to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, wherein the filter is made to perform a filtering operation on EIT is aniah pixels in the block border or close to it, and correction, at least one set of parameter filtering operations based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

34. Video decoder that contains a filter to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, wherein the filter is made to perform a filtering operation on the pixel values at the block border or close to it and correcting at least one of the specified operation parameter of the filter based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

35. The codec of the video signal containing the filter to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, wherein the filter is made to perform a filtering operation on the pixel values at the block border or close to it, and correction of, at least, the underwater setpoint filtering operation, depending at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

36. The mobile terminal containing the filter to reduce the visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, wherein the filter is made to perform a filtering operation on the pixel values at the block border or close to it and correcting at least one of the specified operation parameter of the filter based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

37. A method of coding a video signal, comprising the steps, which reduces visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, characterized in that the steps, which reduces visual distortion caused by the boundary blocks include steps, which perform filtering operation on the pixel values at the block border or close to it is correct, at least one predetermined parameter of the filtering operation based, at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.

38. Method of decoding a video signal, comprising the steps, which reduces visual distortion caused by the boundary blocks between blocks of the image frame of the digital video signal, characterized in that the steps, which reduces visual distortion caused by the boundary blocks include steps, which perform filtering operation on the pixel values at the block border or close to it and adjust at least one parameter filtering operations based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used for encoding a block of the image on the second side of the border blocks.

39. The digital signal processor containing functional elements programmed with functional definitions to reduce the visual distortion caused by the boundary blocks between blocks of the image frame digital VI is eSignal, characterized in that the functional elements of a digital signal processor programmed with functional definitions to perform the filtering operation on the pixel values at the block border or close to it, and for correcting at least one of the specified operation parameter of the filter based at least in part on the encoding method used to encode the block of the image on the first side of the border blocks, and encoding method used to encode the block of the image on the second side of the border blocks.



 

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