JP2011139356A - Display device, display method, program, and record medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that it is difficult for a user to recognize the validity of filtering processing using a de-blocking filter. <P>SOLUTION: In a display device 100 for displaying a decoding image in which block distortion is decreased by a de-blocking filter 505, the display device includes an area specifying part 506 for specifying an area which is an area on the decoding image composed of a plurality of blocks, and maximum in a reduction rate of block distortion by the de-blocking filter and a back end 40 for highlighting the area specified by the specifying means in a display module 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device that decodes encoded data and displays a decoded image. The present invention also relates to a display method for displaying an image using such a display device.

  A decoding device is used to decode the encoded image data. In general, when decoding encoded data encoded using a lossy compression method, encoding noise is generated. In particular, in a method of performing coding / decoding processing in units of blocks, block noise is likely to occur at block boundaries.

  A low-pass filter is known as means for removing coding noise. For example, Patent Document 1 discloses a video signal decoding apparatus including a low-pass filter whose passband is adaptively changed based on a quantization scale code. However, in general, a low-pass filter causes a problem that an image after filtering processing is blurred.

  On the other hand, as described in Non-Patent Document 1 and Non-Patent Document 2, H264. In the AVC standard, a deblocking filter is introduced into a decoding device, and an adaptive filtering process is performed in which a stronger filter process is performed on a portion where block noise is more likely to occur. According to the deblocking filter, it is possible to remove block noise without causing the problem of blurring of the image unlike the low-pass filter.

JP-A-8-84342 (published March 26, 1996)

ITU-T Recommendation H. H.264 “Advanced Video Coding for Generic Audiovisual Services”, 03/2005 Revised version H.264 / AVC textbook, Impress Communications, Inc., 2006

  However, the conventional display device has a problem that it is difficult for the user to immediately recognize the effectiveness of the filtering process by the deblocking filter.

  The present invention has been made in view of the above problems, and its object is to specify a region where the effect of the filtering process by the deblocking filter is large, and to highlight the region, thereby performing the filtering process by the deblocking filter. It is to realize a display device that allows the user to recognize the effect of the above.

In order to solve the above problem, a display device according to the present invention is a display device that displays a decoded image in which block distortion is reduced by a deblocking filter, and is an area on the decoded image that includes a plurality of blocks. And a specifying unit that specifies a region where the reduction rate of block distortion by the deblocking filter is maximized, and a highlighting unit that highlights the region specified by the specifying unit on a display unit. It is said.

  The display device according to the present invention configured as described above is a specifying unit that specifies a region on the decoded image including a plurality of blocks, in which a reduction rate of block distortion by the deblocking filter is maximized. Therefore, for each frame, it is possible to identify a region where the reduction rate of the block distortion by the deblocking filter is maximized, that is, a region where the effect of the filtering process by the deblocking filter is the largest. In addition, since the display device according to the present invention includes highlighting means for highlighting the area specified by the specifying means on the display unit, the area having the greatest effect of reducing block distortion by the deblocking filter is highlighted. By doing so, the effect of the filtering process by the deblocking filter can be recognized by the user.

  Further, the display device according to the present invention can reduce the block distortion reduction rate in each area on the decoded image before and after applying the deblocking filter to pixels adjacent to the block boundary included in the area. It is preferable that calculation means for calculating based on a difference between pixel values is further provided, and the specifying means specifies an area where the reduction rate of the block distortion calculated by the calculating means is maximized.

  In general, block distortion appears prominently at block boundaries.

  According to the above configuration, the reduction rate of the block distortion in each region on the decoded image is determined based on the pixel value before and after the deblocking filter is applied to the pixel adjacent to the block boundary included in the region. It can be calculated based on the difference. Therefore, according to said structure, there exists the further effect that the reduction rate of the said block distortion can be calculated appropriately. Therefore, according to said structure, a user can be made to recognize effectively the effect of the filtering process by a deblocking filter.

  Moreover, in the display device according to the present invention, the calculation means includes pixels before and after applying the deblocking filter to one pixel of a pair of pixels adjacent to each other via a block boundary included in the region. By taking the average of the absolute value of the difference between the values and the absolute value of the difference between the pixel values before and after applying the deblocking filter for the other one of the pixel pairs, the absolute difference It is preferable to calculate a value and calculate a block distortion reduction rate in each region on the decoded image based on an average of the absolute difference values for each of the plurality of pixel pairs included in the region.

  According to the above configuration, the absolute value of the difference between the pixel values before and after applying the deblocking filter for one pixel of the pixel pairs adjacent via the block boundary included in the region, The difference absolute value for the pixel pair is calculated by taking the average of the difference between the pixel values before and after the deblocking filter is applied to the other pixel of the pixel pair, and calculating the difference absolute value Based on the above, the reduction rate of the block distortion can be calculated. Therefore, the reduction rate of the block distortion is more appropriately compared with the case of calculating based on only the absolute value of the difference between the pixel values before and after the deblocking filter is applied to one pixel of the pixel pair. Can be calculated.

  Further, according to the above configuration, it is possible to calculate a block distortion reduction rate in each region on the decoded image based on the average of the absolute difference values for each of the plurality of pixel pairs included in the region. . Therefore, even when the variation of the difference absolute value is large, the block distortion reduction rate can be calculated more appropriately.

Therefore, according to said structure, even if it is a case where the dispersion | variation in the said difference absolute value is large, there exists the further effect that the effect of the filtering process by a deblocking filter can be recognized more effectively by a user.

  In the display device according to the present invention, the reduction rate of block distortion in each region on the decoded image is a parameter associated with the block included in the region, and the on / off of the deblocking process by the deblocking filter is performed. It is preferable that calculation means is further provided for calculating based on a parameter for controlling the calculation, and the specifying means specifies a region where the reduction rate of the block distortion calculated by the calculation means is maximized.

  In general, there is a correlation between a parameter for controlling on / off of deblocking processing by the deblocking filter and a difference between pixel values before and after the deblocking filter is operated.

  According to the above configuration, the block distortion reduction rate in each area on the decoded image is a parameter associated with the block included in the area, and controls on / off of the deblocking process by the deblocking filter. Since a calculation means for calculating based on the parameter is further provided, the block distortion reduction rate can be appropriately calculated. Further, since the reduction rate of the block distortion can be calculated by referring to the parameter instead of referring to the pixel values before and after the deblocking filter is operated, the reduction rate of the block distortion is calculated. There is a further effect that the amount of calculation can be reduced.

  Therefore, according to said structure, the further effect of being able to make a user recognize the effect of the filtering process by a deblocking filter effectively, reducing the calculation amount at the time of calculating the reduction rate of the said block distortion. Play.

  Further, in the display device according to the present invention, the calculation means is a block distortion reduction rate in each region on the decoded image based on an average of the parameters associated with each of a plurality of blocks included in the region. Is preferably calculated.

  According to the above configuration, the calculating unit calculates a block distortion reduction rate in each region on the decoded image based on an average of the parameters associated with each of a plurality of blocks included in the region. Therefore, even when the variation in the parameters is large, the reduction rate of the block distortion can be calculated appropriately.

  Therefore, according to said structure, even if it is a case where the dispersion | variation in the said difference absolute value is large, there exists the further effect that the effect of the filtering process by a deblocking filter can be recognized more effectively by a user.

  In the display device according to the present invention, it is preferable that the highlighting means enlarges and displays the area specified by the specifying means on the display unit.

  According to said structure, since the area | region identified by the said identification means can be expanded and displayed on the said display part, the effect of the filtering process by a deblocking filter can be recognized more effectively by a user. There is an effect.

  Further, in the display device according to the present invention, the highlighting means extracts the area specified by the specifying means for each of a plurality of consecutive frames, stores the area in a memory, and then stores the continuous plurality of frames. It is preferable that the area for each of the frames is sequentially enlarged and displayed on the display unit at predetermined time intervals.

  According to the above configuration, the highlighting means extracts the area specified by the specifying means for each of a plurality of consecutive frames, stores the area in the memory, and stores each of the plurality of consecutive frames. The area of the image is sequentially enlarged and displayed on the display unit at predetermined time intervals, that is, the enlarged area of each of the plurality of consecutive frames can be displayed in slow motion. There is a further effect that the effect of the filtering process by can be recognized more effectively by the user.

  Further, in the display device according to the present invention, the highlighting means displays the area before the deblocking filter is actuated on the display unit together with the area specified by the specifying means for each frame. It is preferable.

  According to said structure, the said highlight display means can display this area | region before making the said deblocking filter act with respect to each flame | frame with the area | region specified by the said specific means. Therefore, the user can recognize the effect of the filtering process by comparing the area after the filtering process by the deblocking filter and the area before the filtering process.

  Therefore, according to said structure, there exists the further effect that the effect of the filtering process by a deblocking filter can be recognized more effectively by a user.

  Further, a program for causing a computer to operate as the display device according to the present invention, the program for causing the computer to function as each means included in the display device, and a computer reading that records the program Possible recording media are also included in the scope of the present invention.

  The display method according to the present invention is a display method for displaying a decoded image in which block distortion has been reduced by a deblocking filter, wherein the display method is an area on the decoded image composed of a plurality of blocks, and the block by the deblocking filter The method includes a specifying step of specifying a region where the distortion reduction rate is maximized, and a highlighting step of highlighting the region specified by the specifying unit on the display unit.

  According to the above method of the present invention, the same effect as the above display device can be obtained.

  As described above, the display device according to the present invention is a display device that displays a decoded image in which block distortion has been reduced by a deblocking filter. Specific means for specifying a region where the reduction rate of the block distortion by the filter is maximized, and highlighting means for highlighting the region specified by the specifying means on the display unit are provided.

  According to said structure, the display apparatus which can make a user recognize the effect of the filtering process by a deblocking filter by specifying the area | region where the effect of the filtering process by the said deblocking filter is large, and highlighting the said area | region Can be realized.

It is a block diagram which shows the structure of the display apparatus which concerns on embodiment. It is a block diagram which shows the structure of the decoder part in the display apparatus which concerns on embodiment. It is for demonstrating the deblocking process by the deblocking filter in the display apparatus which concerns on embodiment, Comprising: (a) is a figure which shows arrangement | positioning of the block which comprises a macroblock, (b) is a deblocking process. It is a figure which shows the pixel value before a blocking process, (c) is a figure which shows the pixel value after a deblocking process. It is a graph for demonstrating the deblocking process by the deblocking filter in the display apparatus which concerns on embodiment, Comprising: It is a graph which shows the relationship between a quantization parameter, threshold value (alpha), and threshold value (beta). FIG. 2 is a diagram for explaining more generally the deblocking process by the deblocking filter in the display device according to the embodiment, in which (a) is a pixel value of a pixel defined by a certain horizontal scanning line, and It is a figure which shows the pixel value before a blocking process, (b) is a figure which shows the pixel value after a deblocking process. FIG. 2 is a diagram for more generally explaining the deblocking process by the deblocking filter in the display device according to the embodiment, in which (a) is a pixel value of a pixel defined by a certain vertical scanning line, and It is a figure which shows the pixel value before a blocking process, (b) is a figure which shows the pixel value after a deblocking process. It is a figure for demonstrating the process by the area | region specific part in the display apparatus which concerns on embodiment, Comprising: It is a figure which shows an example of the image which the encoding data used as the object of the process by an area | region specific part represents. It is for demonstrating the process by the area | region specific part in the display apparatus which concerns on embodiment, Comprising: (a) is a graph which shows the horizontal direction average correction value which an area | region specific part calculates for every horizontal position of a block boundary. And (b) is a graph showing an average value of absolute values of correction values in the vertical direction calculated by the area specifying unit for each vertical position of the block boundary. FIG. 6 is a diagram for explaining processing by the area specifying unit in the display device according to the embodiment, in which (a) represents a moving average of average values of absolute values of horizontal correction values calculated by the area specifying unit as block boundaries; (B) is a graph showing the moving average in the vertical direction calculated by the area specifying unit for each vertical position of the block boundary. For explaining the processing by the area specifying unit in the display device according to the embodiment, the average value of the absolute value of the horizontal correction value accumulated at all block boundaries in a frame in a plurality of consecutive frames, and FIG. 11 is a graph showing an average value of absolute values of correction values in the vertical direction with respect to other specific block boundaries; It is for demonstrating the process by the area | region specific | specification part in the display apparatus which concerns on embodiment, Comprising: (a) is the horizontal position specified for every flame | frame by the area | region specific part with respect to a several continuous flame | frame. (B) is a graph showing the vertical position specified for each frame by the region specifying unit for a plurality of consecutive frames. It is a figure which shows an example of the image | video displayed on the display module in the display apparatus which concerns on embodiment. It is a figure which shows the other example of the image | video displayed on the display module in the display apparatus which concerns on embodiment. It is a figure which shows an example of the image which the video data stored in the memory part in the display apparatus which concerns on the modification of embodiment represents.

  A configuration of the display device 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a display device 100 according to the present embodiment.

  Below, with reference to FIG. 1, the structure of the display apparatus 100 is demonstrated roughly.

As shown in FIG. 1, the display device 100 includes a digital tuner 1, a network terminal 2, an input terminal 3, a front end unit 30, a back end unit 40, a memory unit 50, an OSD (On Screen Display) unit 53, and a display. A module 4 is provided.

  As shown in FIG. 1, the front end unit 30 includes a stream processing unit 31, a decoder unit 32, a video capture unit 33, and a video selection unit 34.

  As shown in FIG. 1, the back end unit 40 includes a first scaler unit 41, a second scaler unit 42, a first image quality correction unit 43, a second image quality correction unit 44, an overlay unit 45, and a control unit. 46 is provided.

  The memory unit 50 includes a first memory area 51 and a second memory area 52.

  An instruction from a user is input to the control unit 46 via a user instruction input unit (not shown). The control unit 46 outputs an instruction signal to each unit of the display device 100 in accordance with an instruction from the user. For example, when receiving a one-screen display instruction from the user, the control unit 46 outputs a one-screen display instruction signal to each unit of the display device 100, and when receiving a two-screen display instruction from the user. A two-screen display instruction signal is output to each part of the display device 100.

  The digital tuner 1 receives a digital broadcast signal such as a terrestrial digital broadcast signal, a BS digital broadcast signal, or a CS digital broadcast signal via an antenna (not shown), selects and demodulates the digital broadcast signal as stream data # 1 Output. The stream data # 1 is, for example, MPEG-TS (Transport Stream). Further, the stream data # 1 is data encoded by a predetermined encoding method.

  On the other hand, the network terminal 2 receives an output from an IP broadcast or an external device via an Ethernet (registered trademark) standard LAN (Local Area Network), and outputs it as stream data # 2. The stream data # 2 is, for example, MPEG-TS or H.264. 264-TS. Stream data # 2 is data encoded by a predetermined encoding method.

  The stream processing unit 31 extracts PES (Packetized Elementary Stream), which is encoded video / audio data included in the stream data # 1 or the stream data # 2, and outputs it as encoded data # 31. In addition, the stream processing unit 31 extracts SI (Service Information) data included in the stream data # 1 or the stream data # 2. The SI data is used to display an EPG (electronic program guide). Also, when the stream data # 1 is scrambled stream data, the stream processing unit 31 performs descrambling of the stream data # 1, that is, descrambling, and then extracts and encodes the PES. Output as data # 31. The same applies to stream data # 2.

  The decoder unit 32 decodes the encoded data # 31 and outputs it as decoded data # 32. Further, when receiving a two-system processing instruction signal described later, the decoder unit 32 outputs decoded data # 32 'in addition to the decoded data # 32. Since the configuration of the decoder unit 32 will be described later, the description thereof is omitted here.

On the other hand, the input terminal 3 receives an analog video signal such as a composite video signal, an S video signal, or a component video signal input from the outside, and supplies the analog video signal to the video capture unit 33. The input terminal 3 receives the decoded digital video signal decoded by the external device and supplies it to the video capture unit 33. The input terminal 3 receives a composite video signal output from an external tuner that has received an analog broadcast signal, and supplies the composite video signal to the video capture unit 33.

  The video capture unit 33 captures the various video signals according to a capture method specific to the various video signals supplied from the input terminal 3, and converts the video signals into video data of a predetermined format. The video data of the predetermined format is output as formatted data # 33.

  The video selection unit 34 selects either one or two of the decoded data # 32, the decoded data # 32 ′, or the formatted data # 33 according to the instruction from the control unit 46, and the memory To the unit 50. Specifically, when the video selection unit 34 receives a one-screen display instruction signal from the control unit 46, the video selection unit 34 includes the decoded data # 32, the decoded data # 32 ′, or the formatted data # 33. Either one is selected and stored in the first memory area 51. In addition, when receiving a two-screen display instruction signal from the control unit 46, the video selection unit 34 selects any one of the decoded data # 32, the decoded data # 32 ′, and the formatted data # 33. Each of the selected data is stored in the first memory area 51 and the second memory area.

  The first scaler unit 41 reads the video data # 51 stored in the first memory area 51, and performs a predetermined resolution conversion process according to the video size represented by the video data # 51 based on an instruction from the control unit 46. To generate first scale-converted data # 41. Specifically, when the first scaler unit 41 receives a one-screen display instruction signal from the control unit 46, the video represented by the video data # 51 has the same size as the display unit of the display module 4. The resolution conversion process is performed to generate first scale-converted data # 41. In addition, when the first scaler unit 41 receives a two-screen display instruction signal from the control unit 46, the first scaler unit 41 converts the resolution so that the video represented by the video data # 51 is half the size of the display unit of the display module 4. Processing is performed to generate first scale-converted data # 41. Note that the video data # 51 corresponds to any of the decoded data # 32, the decoded data # 32 ', or the formatted data # 33 stored in the first memory area 51 through the above-described processing.

  Similarly, the second scaler unit 42 reads the video data # 52 stored in the second memory area 52, and, based on an instruction from the control unit 46, has a predetermined resolution corresponding to the video size represented by the video data # 52. Conversion processing is performed to generate second scale-converted data # 42. Specifically, when the second scaler unit 42 receives a two-screen display instruction signal from the control unit 46, the video represented by the video data # 52 is half the size of the display unit of the display module 4. The resolution conversion process is performed to generate second scale-converted data # 42. Note that the video data # 52 corresponds to any of the decoded data # 32, the decoded data # 32 ', or the formatted data # 33 stored in the second memory area 52 through the above-described processing.

  The first image quality correction unit 43 performs a predetermined image quality correction process on the first scale-converted data # 41 to generate first corrected data # 43.

  Similarly, the second image quality correction unit 44 performs a predetermined image quality correction process on the second scale-converted data # 42 to generate second corrected data # 44.

  A specific example of the predetermined image quality correction process is a high-frequency component removal process using a spatial LPF, an inter-frame LPF, or the like. Another specific example of the predetermined image quality correction processing is image quality correction processing such as edge enhancement.

  The superposition unit 45 combines the first corrected data # 43, the second corrected data # 44, and the OSD image data # 53 supplied from the OSD unit 53 to generate and output display video data # 45. To do.

  The display module 4 displays the video represented by the display video data # 45 on the display unit included in the display module 4.

  In the above description, the video selection unit 34 has exemplified the case where the decoded data # 32, the decoded data # 32 ′, or the formatted data # 33 is output to the memory unit 50. The present invention is not limited thereby. The video selection unit 34 is configured to directly output the decoded data # 32, the decoded data # 32 ′, or the formatted data # 33 to the first skater unit 41 and the second scaler unit 42. Also good. In the above description, the back end unit 40 includes the first scaler unit 41 and the second scaler unit 42 as an example, but the present invention is not limited thereto. For example, the back end unit 40 does not include the first image quality correction unit 43 and the second image quality correction unit 44, and the first scale-converted data # 41 and the second scale-converted data # 42 are Alternatively, a configuration may be adopted in which the data is directly input to the overlapping unit 45.

  The above is the outline of the configuration of the display device 100. Hereinafter, the decoder unit 32 and the control unit 46 will be described in more detail.

  First, the configuration of the decoder unit 32 will be described with reference to FIG.

  FIG. 2 is a block diagram illustrating a configuration of the decoder unit 32 in the display device 100.

  As illustrated in FIG. 2, the decoder unit 32 includes a variable length decoding unit 501, an inverse quantization unit 502, an inverse DCT unit 503, a motion compensation unit 504, a deblocking filter 505, and a region specifying unit 506.

  The variable length decoding unit 501 receives encoded data # 31 in units of macroblocks. The macroblock is a unit of encoding when the encoded data # 31 is generated, and is also a unit of decoding in the decoder unit 32. The macro block is composed of one or a plurality of blocks.

  The variable length decoding unit 501 performs variable length decoding processing on the encoded data # 31. The encoded data # 31 is data in which a plurality of pieces of information are multiplexed, and the variable length decoding unit 501 performs the variable length decoding process so that each block constituting the macroblock is encoded from the encoded data # 31. In addition, a quantized DCT (Discrete Cosine Transform) coefficient, a quantization parameter QP (Quantization Parameter), prediction motion switching information, coding mode information, motion vector information, and the like are extracted.

  In addition, the variable length decoding unit 501 provides first decoding information # 501a and second decoding information # 501b to the inverse quantization unit 502, motion compensation unit 504, deblocking filter 505, and region specifying unit 506, respectively. The third decoding information # 501c and the fourth decoding information # 501d are output.

Here, the first decoding information # 501a includes a quantized DCT coefficient and a quantization parameter QP, and the second decoding information # 501b includes prediction operation switching information, coding mode information, and motion Vector information is included, third decoding information # 501c includes encoding mode information, quantization parameter QP, and motion vector information, and fourth decoding information # 501d includes encoding mode information, And a quantization parameter QP.

  Note that the prediction operation switching information described above is whether the encoded data # 31 is data encoded using the intra prediction mode (intra prediction mode) or the inter prediction mode (inter prediction mode). This is information indicating whether the data is encoded using the data.

  The inverse quantization unit 502 uses the quantization parameter QP included in the first decoded information # 501a to inversely quantize the quantized DCT coefficient included in the first decoded information # 501a in units of blocks. Further, the inverse quantization unit 502 outputs the DCT coefficient # 502 obtained by performing the inverse quantization to the inverse DCT unit 503.

  The inverse DCT unit 503 performs an inverse discrete cosine transform process on the DCT coefficient # 502 for each block. Further, the inverse DCT unit 503 outputs the residual data # 503 obtained by the inverse discrete cosine transform process to the motion compensation unit 504.

  The motion compensation unit 504 adds the residual data # 503 and the predicted image data generated by the residual data input before the residual data # 503 is input, and generates frame decoded image data # 504. Generate. The frame decoded image data # 504 is output to the deblocking filter 505.

  Note that the motion compensation unit 504 uses the motion vector information included in the first decoding information # 501a when the prediction operation switching information included in the first decoding information # 501a indicates the inter-screen prediction mode. The prediction image data is generated by performing the motion compensation, and when the prediction operation switching information included in the first decoding information # 501a indicates the intra prediction mode, it is adjacent to the block to be predicted. The predicted image data is generated on the basis of the pixel values in the already decoded block.

(Deblocking filter 505)
Next, the deblocking filter 505 will be described. In general, the deblocking filter 505 performs frame processing when a difference between pixel values of pixels adjacent to each other via a block boundary or macroblock boundary in the frame decoded image data # 504 is smaller than a predetermined threshold value. Deblocking processing is performed on the block boundary or the macroblock boundary in the decoded image data # 504. Further, the strength of the deblocking process is set in stages according to the coding mode information, the quantization parameter QP, and the motion vector information included in the third decoding information # 501c.

  Below, with reference to FIG. 3, an example of the deblocking process in the deblocking filter 505 is demonstrated concretely.

  FIG. 3A is a diagram illustrating a configuration of a macroblock MB that is a target of deblocking processing. As shown in FIG. 3A, in the following, it is assumed that the size of the macroblock MB is 16 × 16 pixels, and the macroblock MB includes 16 blocks having a size of 4 × 4 pixels. Although described, the present invention is not limited to this. That is, the present invention can be applied even when the size of the macroblock is a size other than 16 × 16 pixels or when the size of the block is a size other than 4 × 4 pixels.

In the following, among the blocks, the blocks are arranged in the same straight line mainly composed of the uppermost four pixels of the block P shown in FIG. 3A and the uppermost four pixels of the block Q. A description will be given by taking a deblocking process for 8 pixels as an example. In the following, deblocking processing in the horizontal scanning direction (hereinafter referred to as the horizontal direction) will be mainly described. However, the deblocking filter 505 is a direction perpendicular to the horizontal scanning direction (hereinafter referred to as the vertical direction). The deblocking process along is performed in the same manner.

  FIG. 3B is a diagram illustrating the pixel values of the eight pixels before the deblocking process, and FIG. 3C is a diagram illustrating the pixel values of the eight pixels after the deblocking process.

  First, as shown in FIG. 3B, the four pixels in the uppermost column of the block P are referred to as a pixel P3, a pixel P2, a pixel P1, and a pixel P0 in order from the left. As shown in FIG. 3B, the pixel values of the pixels P0 to P3 are pixel values p0 to p3, respectively. Similarly, as shown in FIG. 3B, the four pixels in the uppermost column of the block Q are referred to as a pixel Q0, a pixel Q1, a pixel Q2, and a pixel Q3 in order from the left. As shown in FIG. 3B, the pixel values of the pixels Q0 to Q3 are pixel values q0 to q3, respectively. As shown in FIG. 3B, the pixel P0 and the pixel Q0 are pixels adjacent to each other via a block boundary.

  Further, as shown in FIG. 3C, the pixel values of the pixels P0 to P3 and the pixels Q0 to Q3 after the deblocking process are respectively the pixel values p0 ′ to p3 ′ and the pixel values q0 ′ to q3 ′.

  The deblocking filter 505 determines a block boundary strength (Bs value: Boundary Strength) for the eight pixels. Specifically, the deblocking filter 505 determines the Bs value as in the following (1) to (5).

  (1) When at least one of the pixels P0 to P3 or the pixels Q0 to Q3 belongs to an intra (in-screen) macroblock and is located at the boundary of the macroblock MB, Bs = 4. Here, an intra macroblock refers to a macroblock encoded using intra prediction (the same applies hereinafter).

  (2) If any one of the pixels P0 to P3 or the pixels Q0 to Q3 belongs to the intra macroblock but is not located at the boundary of the macroblock MB, Bs = 3.

  (3) When none of the pixels P0 to P3 and the pixels Q0 to Q3 belong to an intra macroblock, and either one of the pixels P0 to P3 or the pixels Q0 to Q3 has an orthogonal transform coefficient Is assumed to be Bs = 2. Here, the orthogonal transform coefficient is, for example, the above-described quantized DCT coefficient, but the present invention is not limited to this. That is, when the encoded data # 31 includes transform coefficients other than quantized DCT transform coefficients such as Hadamard transform coefficients, the orthogonal transform coefficients include those transform coefficients (the same applies hereinafter). .

  (4) None of the pixels P0 to P3 and the pixels Q0 to Q3 belong to the intra macroblock, and none of the pixels P0 to P3 and the pixels Q0 to Q3 have orthogonal transform coefficients, but the reference pictures are different. If the number of reference pictures is different or the value of the motion vector is different, Bs = 1. Here, the reference picture refers to a picture that is referred to in encoding using inter-picture prediction (the same applies hereinafter). The value of the motion vector refers to a motion vector included in the motion vector information described above and assigned to the block to be processed (the same applies hereinafter).

  (5) None of the pixels P0 to P3 and the pixels Q0 to Q3 belong to the intra macroblock, and none of the pixels P0 to P3 and the pixels Q0 to Q3 have an orthogonal transform coefficient, and the reference picture also moves. If the vector values are also the same, Bs = 0.

  The deblocking filter 505 performs stronger deblocking processing on the pixels P0 to P3 and the pixels Q0 to Q3 as the value of Bs determined as described above is larger. That is, the deblocking filter 505 determines the filter strength according to conditions such as whether or not the boundary between the pixels P0 to P3 and the pixels Q0 to Q3 is a macroblock boundary or whether intra prediction is performed. By changing, deblocking processing suitable for each block boundary is executed.

  The deblocking filter 505 performs the deblocking process only when the following conditions (6) and (7) are satisfied.

(6) Bs> 0
(7) | p0-q0 | <α and | p1-p0 | <β and | q1-q0 | <β
Here, the threshold value α and the threshold value β are determined according to the value of the quantization parameter QP described above. FIG. 4 is a graph showing a specific example of the threshold α and the relationship between the threshold β and the quantization parameter QP. The vertical axis in FIG. 4 represents α or β, and the horizontal axis in FIG. 4 represents the value of the quantization parameter QP.

  In addition, the threshold value α and the threshold value β can both give an offset desired by the user by changing a parameter in the bit stream.

  Below, the specific example of the deblocking process in the deblocking filter 505 is given.

  (8) When Bs <4, the input is p1, p0, q0, q1, and the values of p0 ′ and q0 ′ are generated by the following 4-tap FIR (Finite Impulse Response Filter) filter.

Δ = Clip [−tc, tc, {(q0−p0) << 2+ (p1−q1) +4} / 8]
p0 ′ = p0 + Δ
q0 ′ = q0−Δ
Here, Clip [a, b, c] represents that clip processing is performed so that the range of a satisfies a ≦ c ≦ b, and tc is | p2-p0 |, | q2-q0 | , And the value of β.

  If | p2-p0 | is smaller than the threshold value β, the input is p2, p1, p0, q1, and the value of p1 ′ is generated by the following 4-tap FIR filter.

p1 ′ = p1 + Clip [−tc0, tc0, p2 + {(p0 + q0 + 1) − (p1 × 2)} / 2]
Here, the value of tc0 is determined according to Bs and the quantization parameter QP.

  Similarly, when | q2−q0 | is smaller than the threshold value β, the values of q1 ′ are generated by the following 4-tap FIR filter with inputs p2, p1, p0, and q1.

q1 ′ = q1 + Clip [q2 + {(q0 + p0 + 1) − (q1 × 2)} / 2, −tc0, tc0]
(9) When Bs = 4 (9-1) When | p2-p0 | <β and | p0-q0 | <α / 4 + 2 p0 ′ = (p2 + 2 × p1 + 2 × p0 + 2 × q0 + q1) / 8
p1 ′ = (p2 + p1 + p0 + q1) / 4
p2 ′ = (2 × p3 + 3 × p2 + p1 + p0 + q0) / 8
(9-2) Otherwise p0 ′ = (2 × p1 + p0 + q0) / 4
For q0 ′, q1 ′, and q2 ′, in the above (9-1) and (9-2), piｐqi (i = 0, 1, 2, 3), pi′⇔qi It can be obtained by replacing '.

  As described above, the deblocking filter 505 performs the deblocking process for each block adjacent to each other using the pixel values pi and qi of the pixels belonging to the block as input values, and the pixel values pi ′ and qi after the deblocking process. 'Is calculated, and decoded data # 32 is generated based on the pixel value after the deblocking process.

Here, in any of the cases (8) and (9), the correction value Δpx determined by the difference between the calculated pixel values p0 ′ and p0 is:
Δpx = p0′−p0
Further, in any of the cases (8) and (9), the correction value Δqx determined by the difference between the calculated pixel values p0 ′ and p0 is
Δqx = q0′−q0
It is. In the present embodiment, the deblocking filter 505 outputs the absolute value | Δpx | of the correction value for the pixel P0 and the pixel Q0 and the absolute value | Δqx | of the correction value to the region specifying unit 506.

  In addition, this invention is not limited to the specific example of the deblocking process mentioned above. That is, even if the deblocking filter 505 performs a filtering process other than the deblocking process described above, the pixel values p0 and q0 before the filtering process and the pixel value p0 after the filtering process are performed. The absolute values | Δpx | and | Δqx | of the correction values are calculated from “, q0” as described above and output to the region specifying unit 506.

  Further, the deblocking filter 505 performs the filtering process and the calculation of the absolute value | Δpx | of the correction value and the absolute value | Δqx | of the correction value to all the pixels adjacent to each other through the block boundary. The absolute value of the calculated correction value is output to the area specifying unit 506.

  In addition, the deblocking filter 505 performs the deblocking process along the vertical direction in the same manner, and the pixel value before the deblocking process and the pixel value after the deblocking process of the adjacent pixels via the block boundary are obtained. Similar to the absolute value | Δpx | of the correction value and the absolute value | Δqx | of the correction value, the absolute value | Δpy | of the correction value and the absolute value | Δqy | of the correction value are calculated. Output.

  Hereinafter, calculation and allocation of correction values in the deblocking filter 505 will be described more generally with reference to different drawings.

  FIGS. 5A to 5B are diagrams illustrating pixels that are defined by the nth horizontal scanning line and that are adjacent to each other via a block boundary that intersects the nth horizontal scanning line vertically. is there.

As shown in FIG. 5A, the pixels P0, m, n belonging to the block Bm (1 ≦ m ≦ M, M is the total number of blocks to which the pixels defined by the nth horizontal scanning line belong), and Pixels Q0m + 1, n belonging to the block Bm + 1 are adjacent to each other via a boundary BRm between the block Bm and the block Bm + 1. In addition, pixel values before deblocking processing of the pixels P0, m, n and the pixels Q0, m, n are expressed as p0, m, n and q0, m, n, respectively.

  Further, as shown in FIG. 5B, the pixel values after deblocking processing of the pixels P0, m, n and Q0, m, n are respectively represented by p0 ′, m, n and q0 ′, Expressed as m, n.

  The deblocking filter 505 calculates p0 ', m, n according to the above (1) to (9) and assigns it to the pixel P0, m, n. The deblocking filter 505 calculates q0 ', m, n according to the above (1) to (9) and assigns it to the pixel Q0, m, n.

In other words, the deblocking filter 505 applies the p0 to all pixels that are defined by an arbitrary horizontal scanning line and that are adjacent to each other through a block boundary perpendicular to the arbitrary horizontal scanning line. ', m, n and q0', m, n are calculated and assigned. Further, the deblocking filter 505 generates a correction value Δpx, m, n (1 ≦ m ≦ M, 1 ≦ n ≦ N, N is the total number of horizontal scanning lines) Δpx, m, n = p0 ′, m, n− p0, m, n
And the absolute value is output to the area specifying unit 506. Further, the deblocking filter 505 sets the correction value Δqx, m, n (1 ≦ m ≦ M, 1 ≦ n ≦ N) to Δqx, m, n = q0 ′, m, n−q0, m, n.
And the absolute value is output to the area specifying unit 506.

  FIGS. 6A to 6B are diagrams illustrating pixels that are defined by the t-th vertical scanning line and that are adjacent to each other via a block boundary that intersects the t-th vertical scanning line perpendicularly. is there.

As shown in FIG. 6A, the pixels V0, s, t belonging to the block B ′s (1 ≦ s ≦ S, S is the total number of blocks to which the pixels defined by the t-th vertical scanning line belong), and The pixel W0s + 1, t belonging to the block B's + 1 is a boundary BR's between the block B's and the block B's + 1.
Are adjacent to each other. In addition, pixel values before deblocking processing of the pixels V0, s, t and the pixels W0, s, t are represented as v0, s, t and w0, s, t, respectively.

  Further, as shown in FIG. 5B, the pixel values after deblocking processing of the pixels V0, s, t and the pixels W0, s, t are respectively v0 ′, s, t, and w0 ′, Expressed as s, t.

  The deblocking filter 505 calculates v0 ', s, t according to the above (1) to (9) and assigns it to the pixel V0, s, t. Further, the deblocking filter 505 calculates w0 ', s, t according to the above (1) to (9) and assigns it to the pixel W0, s, t.

In other words, the deblocking filter 505 applies the above v0 to all pixels that are defined by an arbitrary vertical scanning line and that are adjacent to each other through a block boundary perpendicular to the arbitrary vertical scanning line. ', s, t and w0', s, t are calculated and assigned. Further, the deblocking filter 505 converts the correction value Δpy, s, t (1 ≦ s ≦ S, 1 ≦ t ≦ T, T is the total number of vertical scanning lines) into Δpys, t = v0 ′, s, t−v0, s, t
And the absolute value is output to the area specifying unit 506. Further, the deblocking filter 505 converts the correction value Δqy, s, t (1 ≦ s ≦ S, 1 ≦ t ≦ T) into Δqys, t = w0 ′, s, t−w0, s, t.
And the absolute value is output to the area specifying unit 506.

  Further, the deblocking filter 505 calculates the absolute value of the correction value for all frames input to the deblocking filter 505 and outputs the absolute value to the region specifying unit 506.

(Area specifying unit 506)
Next, the area specifying unit 506 will be described.

  The area specifying unit 506 is a means for specifying an area where the effect of the deblocking process in the deblocking filter 505 is more remarkable. In other words, the region specifying unit 506 converts the pixel value of the block before the deblocking process is performed in the deblocking filter 505 and the pixel value of the block after the deblocking process is performed in the deblocking filter 505. Based on this, an area where the effect of the deblocking process is more remarkable is identified.

  Hereinafter, the region specifying unit 506 will be described with reference to FIGS.

  First, the case where the decoder unit 32 is decoding encoded data # 31 representing video as shown in FIG. 7 will be described as an example.

  FIG. 7 is a CG image in which a cloud quickly passes over a stationary background from the upper right to the lower left, and a stationary telop is superimposed on the center of the screen. The arrows in FIG. 7 indicate the moving direction of the clouds. In a moving part such as a cloud shown in FIG. 7, since the video changes in a complicated manner, the block noise tends to be remarkable.

First, the region specifying unit 506 first calculates the absolute value | Δpx, m, n | (1 ≦ m ≦ M, 1 ≦ n ≦ N) of the correction value input from the deblocking filter 505 and the absolute value | Δqx, The average value Ax, n, m (of the absolute value of the correction value) with m + 1, n | is Ax, n, m = (| Δpx, m, n | + | Δqx, m + 1, n |) / 2
To obtain the absolute value of the correction value at the block boundary BRm.

The region specifying unit 506 also outputs the absolute value | Δpy, s, t | (1 ≦ s ≦ S, 1 ≦ t ≦ T) of the correction value input from the deblocking filter 505 and the absolute value | Δqy of the correction value. , s + 1, t | is the average value Ay, s, t (of the absolute value of the correction value) Ay, s, t = (| Δpy, s, t | + | Δqy, s + 1, t |) / 2
To obtain the absolute value of the correction value at the block boundary BR's.

In other words, the area specifying unit 506 determines the absolute value of the correction value in a pixel defined by an arbitrary horizontal scanning line and adjacent to each other via a block boundary perpendicularly intersecting the arbitrary horizontal scanning line. The average value Ax, n, m (1 ≦ m ≦ M, 1 ≦ n ≦ N) (the absolute value of the correction value) is calculated by averaging the pixels adjacent to each other, and correction at the block boundary is performed. The absolute value. Further, the region specifying unit 506 is a pixel defined by an arbitrary vertical scanning line, and calculates the absolute value of the correction value in pixels adjacent to each other via a block boundary perpendicular to the arbitrary vertical scanning line. The average value Ay, s, t (1 ≦ s ≦ S, 1 ≦ t ≦ T) (the absolute value of the correction value) is calculated by averaging each adjacent pixel, and the correction value at the block boundary is calculated. Absolute value.

  In general, block noise is larger at block boundaries where the average of the absolute values of the correction values is larger.

The area specifying unit 506 also includes the absolute value | Δpx, m, n | (1 ≦ m ≦ M, 1 ≦ n ≦ N) of the correction value, the absolute value | Δqx, m, n | Absolute value | Δpy, s, t | (1 ≦ s ≦ S, 1 ≦
t ≦ T) and the absolute value | Δqy, s, t | of the correction value are preferably stored in the internal memory. In addition to the absolute value of the correction value, or in place of the absolute value of the correction value, the area specifying unit 506 calculates the average value Ax, n, m of the absolute value of the correction value and the absolute value of the correction value. The average value Ay, s, t of the values may be stored in the internal memory.

  FIG. 8A is a graph showing the average value Ax, m, n of the absolute value of the correction value calculated by the area specifying unit 506 for each block boundary position, and the vertical axis indicates the absolute value of the correction value. The average value Ax, m, n is represented, and the horizontal axis represents the horizontal position of the block boundary on the screen along AA ′ in FIG.

  As shown in FIG. 8A, the average value Ax, m, n of the absolute value of the correction value is smaller in the central portion in the horizontal direction on the screen than in the other areas. This corresponds to the fact that a stationary telop is displayed at the center of the screen as shown in FIG. Further, as shown in FIG. 8A, in the region other than the central portion, the average value Ax, m, n of the absolute value of the correction value is larger. This corresponds to the fact that a moving cloud is displayed in a region other than the central portion.

  Similarly, FIG. 8B is a graph showing the average value Ay, s, t of the absolute value of the correction value calculated by the area specifying unit 506 for each position of the block boundary, and the vertical axis indicates the correction value. The absolute value average value Ay, s, t is represented, and the horizontal axis represents the position of the block boundary in the vertical direction along the line BB ′ in FIG.

The area specifying unit 506 calculates a moving average along the horizontal direction of the average value Ax, m, n of the absolute value of the correction value assigned to the block boundary BRm. Specifically, for example, the region specifying unit 506 calculates the moving average MAx, m, n as MAx, m, n = ΣAx, k, n × (1 / R).
Calculated by Here, Σ represents a block boundary at which the nth horizontal scanning line intersects, and represents a sum related to a block boundary group including a plurality of block boundaries including the mth block boundary BRm, and R represents the block boundary group. Represents the number of block boundaries included in. The subscript k is a subscript for identifying a block boundary belonging to the block boundary group, and the number of block boundaries included in the block boundary group is predetermined.

As specific elements of the block boundary group, for example, a block boundary included in a predetermined range in the horizontal direction around the block boundary BRm may be taken. For example, when the block boundaries included in a predetermined range in the horizontal direction around the block boundary BRm are the block boundaries BRm-2, BRm-1, BRm, BRm + 1, BRm + 2, The moving average MAX, m, n is
MAx, m, n = (Ax, m-2, n + Ax, m-1, n + Ax, m, n + Ax, m + 1, n + Ax, m + 2, n) / 5
Can be calculated.

  The area specifying unit 506 calculates the moving average MAx, m, n for all m, and specifies the value of m that maximizes the value of the moving average MAx, m, n. In other words, the area specifying unit 506 calculates the moving average along the horizontal direction of the average value Ax, m, n of the absolute value of the correction value, and specifies the horizontal position where the moving average value is maximum. To do.

Similarly, the area specifying unit 506 calculates a moving average along the vertical direction of the average value Ay, s, t of the absolute value of the correction value assigned to the block boundary BR ′s. Specifically, the area specifying unit 506 calculates the moving average MAx, m, n as MAy, s, t = ΣAy, u, t × (1 / R ′).
Calculated by Here, Σ represents a block boundary at which the t-th vertical scanning line intersects, and represents a sum related to a block boundary group including a plurality of block boundaries including the s-th block boundary BR ′s, and R ′ represents the block boundary. This represents the number of block boundaries included in the group. The subscript u is a subscript for identifying a block boundary belonging to the block boundary group, and the number of block boundaries included in the block boundary group is predetermined.

The area specifying unit 506 calculates the moving average MAy, s, t for all s, and specifies the value of s that maximizes the value of the moving average MAy, s, t. In other words, the area specifying unit 50
6 calculates the moving average along the vertical direction of the average value Ay, s, t of the absolute value of the correction value, and specifies the position in the vertical direction where the moving average value is maximum. That is, the region specifying unit 506 has a horizontal length Sx and a vertical length Sy centered on a region ((X0, Y0)) where the reduction rate of block distortion by the deblocking filter 505 is maximum. A certain area).

  In the above example, the case where a simple average is taken as the moving average has been described, but the present invention is not limited to this. That is, as the moving average, a weighted average may be used instead of the simple average, or another average calculation may be used.

  FIG. 9A shows the moving average MAx, m, n calculated by the area specifying unit 506 and the moving average taken for a range in which the horizontal length is a predetermined length Sx. It is a graph which shows the value of. The vertical axis in FIG. 9A represents the value of the moving average MAx, m, n, and the horizontal axis represents the horizontal position on the screen of the block boundary along AA ′ in FIG. Represents. As shown in FIG. 9A, the area specifying unit 506 specifies the horizontal position X0 on the screen where the value of the moving average MAx, m, n is the largest.

  Similarly, FIG. 9B is taken with respect to a range in which the moving average MAy, s, t calculated by the region specifying unit 506 and the vertical length is a predetermined length Sy. It is a graph which shows the value of the moving average. The vertical axis in FIG. 9B represents the value of the moving average MAy, s, t, and the horizontal axis represents the position of the block boundary in the vertical direction along the line BB ′ in FIG. Represents. As shown in FIG. 9B, the area specifying unit 506 specifies the vertical position Y0 on the screen where the value of the moving average MAy, s, t is the largest.

  Block noise is more prominent in the range of the length Sx centered on the horizontal position X0 on the screen, and block noise is more prominent in the range of the length Sy centered on the vertical position Y0 on the screen. is there.

  In other words, in the video shown in FIG. 7, a block is generated in a region R (hereinafter referred to as a specific region R) in which the horizontal length around (X0, Y0) is Sx and the vertical length is Sy. Noise is more pronounced. In other words, in the specific region R, the effect of the deblocking process in the deblocking filter 505 appears more significantly.

  The area specifying unit 506 outputs specific area information # 506, which includes information on the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy, to the control unit 46 for each frame. .

  In the above description, the region specifying unit 506 specifies the position where the moving average value is maximized independently in the horizontal direction and the vertical direction, but the present invention is limited to this. It is not a thing. For example, the region specifying unit 506 may specify the position where the sum of the moving average MAx, m, n and the moving average MAy, s, t is maximum, or may specify the position by other methods.

  In addition, the area specifying unit 506 maximizes the average value Ax, n, m of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value without taking the moving average. The position may be specified and information indicating the position may be output to the control unit 46, or the average value Ax, n, m of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value A position where the sum is maximum may be specified, and information representing the position may be output to the control unit 46.

  Further, instead of taking the moving average described above, the region specifying unit 506 performs frequency conversion on the set of absolute values of the correction values and removes high frequency components, thereby removing the average value of the absolute values of the correction values. May be specified, the point where the average value of the absolute values of the smoothed correction values is maximized may be specified, and information indicating the position may be output to the control unit 46.

  The values of the lengths Sx and Sy may be determined in advance, or the average value Ax, m, n (1 ≦ m ≦ M) of the absolute value of the correction value and the correction value You may determine according to the breadth of distribution of the average value Ay, s, t (1 <= s <= S) of absolute value. For example, when the spread of the distribution of the average value Ax, m, n (1 ≦ m ≦ M) of the absolute value of the correction value is larger, the value of Sx is made larger and the average value Ay of the absolute value of the correction value , s, t (1 ≦ s ≦ S) may be larger when the spread of the distribution is larger.

  In addition, the area specifying unit 506 replaces the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value with the absolute value of the correction value regarding a plurality of frames. The average value Ax, m, n of the average value and the average value Ay, s, t of the absolute values of the correction values for a plurality of frames may be used. Specifically, the area specifying unit 506 calculates the average of the absolute value Ax, m, n of the correction value with respect to several tens frames and the average value Ay, s, t of the absolute value of the correction value. An average for may be used.

  The area specifying unit 506 also determines that the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value are equal to or greater than a predetermined threshold value. In addition, the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy are preferably output to the control unit 46.

  FIG. 10 is a graph showing an average value Ax, m, n of absolute values of correction values and an average value Ay, s, t of absolute values of correction values for a specific block boundary in a plurality of consecutive frames. The vertical axis in FIG. 10 represents the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value, and the horizontal axis represents the frame number. Represents. 10 represents the average value Ax, m, n of the absolute value of the correction value, and the triangle mark of FIG. 10 represents the average value Ay, s, t of the absolute value of the correction value. Yes. Since the frame numbers are assigned in the order of the frames to be displayed, FIG. 10 shows the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s of the absolute value of the correction value. , t can be interpreted as a graph representing the time change of t.

  For example, when the average value Ax, m, n of the absolute value of the correction value is equal to or larger than the threshold value Th1 shown in FIG. 10, the region specifying unit 506 calculates the average value Ax, m, n of the absolute value of the correction value. The average value Ay, s, t, Sx and Sy of the absolute value of the correction value may be output, or the average value Ay, s, t of the absolute value of the correction value is a threshold value Th2 shown in FIG. In the above case, the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s, t, Sx, and Sy of the absolute value of the correction value may be output.

  In the period T shown in FIG. 10, the average value Ax, m, n of the absolute value of the correction value and the average value Ay, s, t of the absolute value of the correction value are greater than or equal to the threshold value Th1 and the threshold value Th2, respectively. It shows a certain period.

  FIG. 11A is a graph showing the horizontal position X0 specified for each frame by the region specifying unit 506 with respect to a plurality of continuous frames. In FIG. 11A, the vertical axis indicates the horizontal position X0 specified for each frame, and the horizontal axis indicates the frame number of each frame.

  Similarly, FIG. 11B is a graph showing the vertical position Y0 specified for each frame by the region specifying unit 506 for a plurality of consecutive frames. In FIG. 11B, the vertical axis indicates the vertical position Y0 specified for each frame, and the horizontal axis indicates the frame number of each frame.

  A period T shown in FIGS. 11A and 11B is the same period as the period T shown in FIG. As shown in FIGS. 11A and 11B, in the period T, the horizontal position X0 and the vertical position Y0 are less varied than in other periods.

  As described above, the area specifying unit 506 has the average value Ax, m, n of the absolute value of the correction value or the average value Ay, s, t of the absolute value of the correction value equal to or greater than a predetermined threshold value. In this case, it is preferable to output average values Ax, m, n, Ay, s, t, Sx, and Sy of absolute values of correction values. By adopting such a configuration, it is possible to output the horizontal position X0 and the vertical position Y0 with less fluctuation. In other words, the specific region R with less positional fluctuation can be displayed on the display module 4. This makes it possible to display a demo video that is easy for the user to see.

In the above description, the region specifying unit 506 calculates the moving average along the horizontal direction of the average value Ax, m, n of the absolute value of the average correction value assigned to the block boundary BRm. Is not limited to this. That is, the region specifying unit 506 calculates a moving average along the horizontal direction of the absolute value | Δpx, m, n | of the correction value, and specifies the block boundary BRm having the maximum moving average value. It is good. The region specifying unit 506 calculates a moving average along the horizontal direction of the absolute value | Δqx, m, n | of the correction value, and specifies the block boundary BRm having the maximum moving average value. It is good. Similarly, the area specifying unit 50
6 may be configured such that a moving average along the vertical direction of the absolute value | Δpy, s, t | of the correction value is calculated, and the block boundary BR ′s having the maximum moving average value is specified. Further, the region specifying unit 506 calculates a moving average along the vertical direction of the absolute value | Δqy, s, t | of the correction value, and specifies a block boundary BR ′s having the maximum moving average value. It is good.

(Operation of Display Device 100 in Demo Mode)
Below, the flow of operation of the display device 100 when the display of the demo mode is instructed by the user will be described. Note that the demo mode refers to a mode in which the effect of filtering processing by the deblocking filter 505 in the display device 100 is emphasized and displayed based on an instruction from the user. The display panel 1 may be configured such that the end user instructs the demo mode via the remote controller, or displays the demo mode when a B-CAS card for demo mode is inserted at the store. .

  When receiving a demonstration mode display instruction from the user, the control unit 46 outputs a two-system processing instruction signal # 46a to the decoder unit 32, and outputs video selection information # 46b and display to the video selection unit 34. Position information # 46c is output.

Here, the video selection information # 46b refers to any decoded data of the decoded data # 32 or the decoded data # 32 ′ input to the video selection unit 34 in the first memory area 51.
Stored in the second memory area 52, and the remaining other decoded data should be stored in the second memory area 52. The frames stored in the first memory area 51 or the second memory area 52 may be all frames or a specific part of the frames. The display position information # 46c is information indicating which part of the video represented by the data output from the video selection unit is to be cut out and written into the memory unit 50.

  Upon receiving the two-system processing instruction signal # 46a, the decoder unit 32 receives the decoded data # 32 obtained by performing the deblocking process in the deblocking filter 505 on the encoded data # 31, and the deblocking in the deblocking filter 505. The decoded data # 32 ′ that has not been processed is output to the video selection unit.

  In addition, when the decoder unit 32 receives the two-system processing instruction signal # 46a, the information including the information on the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy specified by the region specifying unit 506 is provided. The specific area information # 506 is output to the control unit 46.

  The control unit 46 converts the area information # 46d including the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy information supplied from the decoder unit 32 into a scaler unit 41, a scaler unit 42, and Output to the OSD unit 53.

  On the other hand, the video selection unit 34 stores the decoded data # 32 in the first memory area 51 and the decoded data # 32 ′ in the second memory area based on the video selection information # 46b and the display position information # 46c. 52.

  The first scaler unit 41 reads the video data # 51 stored in the first memory area 51 and converts it to a predetermined video size. The converted video is output as first scale-converted data # 41. The video data # 51 corresponds to the decoded data # 32.

  Similarly, the second scaler unit 42 reads the video data # 52 stored in the second memory area 52 and converts it to a predetermined video size. The converted video is output as second scale-converted data # 42. The video data # 52 corresponds to the decoded data # 32 '.

  The first image quality correction unit 43 performs a predetermined image quality correction process on the scale-converted data # 41 to generate first corrected data # 43. The first post-correction data # 43 is output to the overlay unit 45.

  Similarly, the second image quality correction unit 44 performs predetermined image quality correction processing on the scale-converted data # 42 to generate second corrected data # 44. The second post-correction data # 44 is output to the overlay unit 45.

  On the other hand, the OSD unit 53 generates an image indicating the boundary line of the specific region R having a horizontal length of Sx and a vertical length of Sy centered on (X0, Y0). The OSD unit 53 outputs OSD image data # 53 including an image indicating the boundary line to the overlay unit 45.

  The superimposing unit 45 combines the first corrected data # 43, the second corrected data # 44, and the OSD image data # 53 supplied from the OSD unit 53 for each frame, and displays the display video data # 45. Generate and output every frame.

  The display module 4 displays the video represented by the display video data # 45 on the display unit included in the display module 4.

  FIG. 12 is a diagram illustrating an example of an image displayed on the display module 4. As shown in FIG. 12, an image that has been subjected to deblocking processing is displayed on the left half surface of the display module 4, and an image that has not been subjected to deblocking processing is displayed on the right half surface of the display module 4. . Further, the specific area R specified by the area specifying unit 506 is surrounded by a dotted line generated by the OSD unit 53.

  By performing such display, the user can visually recognize an area where the effect of the deblocking process is remarkable.

  FIG. 13 is a diagram illustrating another example of the video displayed on the display module 4. As shown in FIG. 13, the display device 100 enlarges and displays the specific region R surrounded by the frame in FIG. 12.

  In order to perform the display as shown in FIG. 13, for example, the first scaler 41 cuts out the specific area R from the video indicated by the video data # 51, converts it to a predetermined video size, and then performs the first scale conversion. The second scaler section 42 cuts out the specific area R from the video indicated by the video data # 52, converts it to a predetermined video size, and outputs it as the second scale-converted data # 41. Such a configuration may be adopted.

  By performing the display as shown in FIG. 13, the user can clearly see the effect of the deblocking process.

  As described above, the display device 100 according to the present embodiment is a region on the decoded image including a plurality of blocks in the display device that displays the decoded image in which the block distortion is reduced by the deblocking filter 505. A specifying unit (region specifying unit 506) that specifies a region where the reduction rate of block distortion by the deblocking filter is maximized, and a highlight display that highlights the region specified by the specifying unit on the display unit (display module 4). Means (back end unit 40).

  The display device 100 according to the present embodiment configured as described above specifies an area on the decoded image including a plurality of blocks, in which the reduction rate of the block distortion by the deblocking filter 505 is maximized. Since the specifying means (area specifying unit 506) is provided, the effect of the filtering process by the deblocking filter 505, that is, the area where the reduction rate of the block distortion by the deblocking filter 505 is maximized for each frame is provided. The largest area can be identified. In addition, the display device 100 according to the present embodiment includes a highlighting display unit (back end unit 40) that highlights the region specified by the specifying unit (region specifying unit 506) on the display unit (display module 4). Therefore, by highlighting the area where the effect of reducing the block distortion by the deblocking filter is highlighted, the effect of the filtering process by the deblocking filter 505 can be recognized by the user.

  Note that the display device 10 according to the present embodiment emphasizes by enlarging and displaying the region where the block distortion reduction rate is maximized, but the method of highlighting the region where the block distortion reduction rate is maximized is displayed. Is not limited to this. For example, by enclosing an area where the block distortion reduction rate is maximized with a frame or by masking an area other than the area where the block distortion reduction rate is maximized, an area where the block distortion reduction rate is maximized is selected. It may be emphasized.

Further, as described above, the display device 100 according to the present embodiment determines the reduction rate of the block distortion in each area on the decoded image with respect to the pixel adjacent to the block boundary included in the area. The image processing apparatus further includes a calculation unit (region specifying unit 506) that calculates based on a difference between pixel values before and after the blocking filter 505 is applied, and the specifying unit (region specifying unit 506) uses the calculation unit (region specifying unit 506). An area (specific area R) in which the calculated reduction rate of block distortion is maximized is specified.

  In general, block distortion appears prominently at block boundaries.

  According to said structure, the pixel distortion value before and behind making the said deblocking filter 505 operate | move about the pixel which adjoins the block boundary contained in this area | region about the block distortion reduction rate in the said decoded image. Can be calculated based on the difference. Therefore, according to the above configuration, the reduction rate of the block distortion can be calculated appropriately. Therefore, according to said structure, the effect of the filtering process by the deblocking filter 505 can be recognized to a user effectively.

In addition, as described above, in the display device 100 according to the present embodiment, the calculation unit (region specifying unit 506) includes one of the pixel pairs adjacent to each other via the block boundary BRm included in the region. The absolute value | Δpx, m, n | of the difference between the pixel values before and after the deblocking filter 505 is applied to the pixel P0, m, n and the other pixel Q0, m + 1 of the pixel pair , n, the average Ax, n, m = (| Δpx, m, n | + |) of the absolute value | Δqx, m + 1, n | before and after the deblocking filter 505 is applied Δqx, m + 1, n |) / 2 is calculated to calculate the absolute difference value Ax, n, m for the pixel pair, and the average of the absolute difference values for each of the plurality of pixel pairs included in the region The block distortion reduction rate in each area on the decoded image is calculated based on the above.

  According to the above configuration, the block distortion of the pixel pair is compared with the case of calculating based on only the absolute value of the difference between the pixel values before and after the deblocking filter 505 is applied to one pixel of the pixel pair. The reduction rate can be calculated more appropriately.

  Further, according to the above configuration, it is possible to calculate a block distortion reduction rate in each region on the decoded image based on the average of the absolute difference values for each of the plurality of pixel pairs included in the region. . Therefore, even when the variation of the difference absolute value is large, the block distortion reduction rate can be calculated more appropriately.

  Therefore, according to said structure, even if it is a case where the dispersion | variation in the said difference absolute value is large, the effect of the filtering process by the deblocking filter 505 can be recognized more effectively by a user.

  Further, as described above, in the display device 100 according to the present embodiment, the highlighting unit (back end unit 40) identifies the region (specific region R) specified by the specifying unit (region specifying unit 506). An enlarged display is performed on the display unit (display module 4).

  According to said structure, since the area | region specified by the said specific means (area | region specific | specification part 506) can be expanded and displayed, the effect of the filtering process by a deblocking filter can be recognized effectively by a user.

  Further, as described above, in the display device 100 according to the present embodiment, the highlighting means (back end unit 40) performs the region (specification) specified by the specifying unit (region specifying unit 506) for each frame. Along with the region R), the region before the deblocking filter 505 is operated is displayed on the display unit (display module 4).

  According to said structure, the user can recognize the effect of the said filtering process by comparing this area | region after the filtering process by the deblocking filter 505, and this area | region before a filtering process.

  Therefore, according to said structure, there exists the further effect that the effect of the filtering process by the deblocking filter 505 can be recognized more effectively by a user.

(Modification 1)
In the above description, the deblocking filter 505 calculates the absolute value | Δpy, s, t | of the correction value and the absolute value | Δqy, s, t | of the correction value, and the region specifying unit 506 Although the specific region R is specified based on the absolute value of the value, the present invention is not limited to this. The display device according to the present invention may be configured to identify the specific region R based on primary decoding information such as the quantization parameter QP and the coding mode information obtained by the variable length decoding unit 501.

  For example, the deblocking filter 505 replaces the absolute value | Δpy, s, t | of the correction value and the absolute value | Δqy, s, t | of the correction value with the value of the quantization parameter QP for each block. The threshold value α and the threshold value β determined accordingly are output to the region specifying unit 506, and the region specifying unit 506 specifies the specific region R based on the threshold value α and the threshold value β. It is good also as such a structure.

  Below, the 1st modification of this embodiment is demonstrated.

  As described in the above conditions (6) and (7), the deblocking filter 505 has a positive Bs value and the absolute value of the difference between the pixel values of pixels adjacent to each other via the block boundary is the threshold value α. And the pixel value of one of the adjacent pixels and the pixel value of a pixel that is on one side of the one pixel and that is in contact with the opposite side of the side that is in contact with the block boundary. The absolute value of the difference is less than the threshold value β, and the pixel value of the other pixel adjacent to each other and one side of the other pixel that is in contact with the block boundary The deblocking process is performed when the absolute value of the difference between the pixel value of the pixel in contact with the opposite side is less than the threshold value β.

  Therefore, in general, when the value of the threshold value α is larger, even if the difference between the pixel values of pixels adjacent to each other via the block boundary is larger, it can be a target of deblocking processing. Therefore, when the threshold value α is larger, the absolute value of the difference between the pixel value before the deblocking process and the pixel value after the deblocking process tends to be larger. That is, when the value of the threshold α is larger, the effect of the deblocking process by the deblocking filter 505 tends to appear more remarkably. The same applies to the threshold value β.

  The area specifying unit 506 in this modification example specifies a block having the largest threshold value α input from the deblocking filter 505, sets the horizontal position of the block to the horizontal position X0, and sets the vertical position of the block to the above-described vertical position. Set to vertical position Y0. Further, the length Sx and the length Sy are determined in accordance with the spread of the horizontal distribution of the threshold value α and the spread of the vertical distribution of the threshold value β, respectively.

  Note that the area specifying unit 506 may specify a block having the largest threshold α after taking the moving average as described above for the set of threshold α.

  In addition, the area specifying unit 506 in this modification may use the threshold β instead of the threshold α, or may use the sum of the threshold α and the threshold β.

  The area specifying unit 506 outputs specific area information # 506, which is information including the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy set as described above, to the control unit 46.

  Configurations other than the deblocking filter 505 and the region specifying unit 506 are the same as those already described.

  In this modification, the deblocking filter 505 does not need to calculate the correction value Δpy, s, t and the correction value Δqy, s, t, and thus the configuration of the deblocking filter 505 is simplified. be able to.

  As described above, the display device according to the present modified example is a parameter associated with the block included in the area, and the deblocking filter by the deblocking filter determines the block distortion reduction rate in each area on the decoded image. The image processing apparatus further includes a calculation unit (region specifying unit 506) that calculates based on parameters (the threshold value α and the threshold value β) that control ON / OFF of the blocking process, and the specifying unit (region specifying unit 506) includes the calculation unit. The region where the block distortion reduction rate calculated by (region specifying unit 506) is maximized is specified.

  In general, there is a correlation between a parameter for controlling on / off of deblocking processing by the deblocking filter (the threshold α and the threshold β) and a difference between pixel values before and after the deblocking filter is operated. To do.

  According to said structure, the reduction rate of the said block distortion can be calculated appropriately. Further, since the reduction rate of the block distortion can be calculated by referring to the parameter instead of referring to the pixel values before and after the deblocking filter 505 is operated, the reduction rate of the block distortion is calculated. This can reduce the amount of calculation.

  Therefore, according to the above configuration, it is possible to make the user effectively recognize the effect of the filtering process by the deblocking filter 505 while reducing the amount of calculation when calculating the reduction rate of the block distortion.

  Further, as described above, in the display device according to the present modification, the calculation unit (region specifying unit 506) is configured to associate the parameter (the threshold α and the threshold α) associated with each of a plurality of blocks included in the region. The block distortion reduction rate in each region on the decoded image is calculated based on the average of the threshold values β).

  According to the above configuration, the reduction rate of the block distortion can be appropriately calculated even when the variation in the parameters is large.

  Therefore, according to said structure, even if it is a case where the dispersion | variation in the said difference absolute value is large, the effect of the filtering process by the deblocking filter 505 can be recognized more effectively by a user.

(Modification 2)
In the above description, as shown in FIG. 12, a configuration has been described in which a region other than the region specified by the region specifying unit 506 is also displayed on the display module 4, but the present invention is not limited to this. Absent. Below, the 2nd modification of this embodiment is demonstrated with reference to FIG.

  In this modification, the control unit 46 outputs display range information to the video selection unit 34 in addition to the video selection information # 46b and the display position information # 46c. Here, the display range information is substantially the same information as the specific area information # 506 input to the control unit 46, and the horizontal position X0, the vertical position Y0, the length Sx, and the length Sy of the specific area R are set. It is information to include.

  The video selection unit 34 extracts only the range included in the specific region R from the plurality of frames represented by the decoded data # 32 based on the display range position information, and sequentially stores the range in the first memory region 51. Further, the video selection unit 34 extracts only the range included in the specific region R from the plurality of frames represented by the decoded data # 32 ′ based on the display range position information, and sequentially stores it in the second memory region 52. To do.

  In this modification, the memory capacity of the first memory area and the second memory area is reduced by storing the areas other than the specific area R in the first memory area and the second memory area as described above. It can be used more effectively.

  FIG. 14 is a diagram illustrating an example of an image represented by the video data # 51 stored in the first memory area 51. As shown in FIG. 14, in this modification, the specific area R is extracted from 18 consecutive frames and stored in the first memory area 51. The display device according to this modification may be configured to display the specific areas R for 18 frames side by side, or sequentially display the specific areas R for 18 frames at predetermined time intervals. Depending on the situation, it may be configured to display slow motion.

  According to the display device according to this modification, the effect of the deblocking process in the deblocking filter 505 can be recognized more clearly by the user.

  As described above, in the display device according to this modification, the highlighting means (back end unit 40) extracts the area specified by the specifying means for each of a plurality of continuous frames, and then extracts the area. Are stored in the memory 50, and the region for each of the plurality of consecutive frames is sequentially enlarged and displayed on the display unit (display module 4) at predetermined time intervals.

  According to said structure, since the said area | region expanded about each of the said several continuous flame | frame can be displayed in slow motion, the effect of the filtering process by a deblocking filter can be recognized effectively by a user. it can.

(Program and recording medium)
Finally, each block included in the control unit 46 and the decoder unit 32 of the display device 100 may be configured by hardware logic. Alternatively, it may be realized by software using a CPU (Central Processing Unit) as follows.

  That is, the control unit 46 and the decoder unit 32 include a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the program, and a RAM (Random Access) that expands the program into an executable format. Memory) and a storage device (recording medium) such as a memory for storing the program and various data. With this configuration, the object of the present invention can also be achieved by a predetermined recording medium.

  This recording medium only needs to record the program code (execution format program, intermediate code program, source program) of the program of the control unit 46 and the decoder unit 32, which is software that realizes the above-described functions, in a computer-readable manner. . The recording medium is supplied to the control unit 46 and the decoder unit 32. Thus, the control unit 46 and the decoder unit 32 (or CPU or MPU) as a computer may read and execute the program code recorded on the supplied recording medium.

  The recording medium that supplies the program code to the control unit 46 and the decoder unit 32 is not limited to a specific structure or type. That is, the recording medium includes, for example, a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. System, a card system such as an IC card (including a memory card) / optical card, or a semiconductor memory system such as a mask ROM / EPROM / EEPROM / flash ROM.

  Further, even if the display device 100 is configured to be connectable to a communication network, the object of the present invention can be achieved. In this case, the program code is supplied to the display device 100 via the communication network. The communication network is not limited to a specific type or form as long as it can supply the program code to the display device 100. For example, it may be the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication network, and the like.

  The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, wired communication such as IEEE 1394, USB (Universal Serial Bus), power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line, infrared rays such as IrDA and remote control, Bluetooth (registered trademark), 802.11 It can also be used by radio such as radio, HDR, mobile phone network, satellite line, terrestrial digital network. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be suitably applied to a display device that decodes encoded data and displays a decoded image.

100 Display device 4 Display module (display unit)
31 Stream processing unit 32 Decoder unit 505 Deblocking filter 506 Area specifying unit (specifying means)
33 Video capture unit 34 Video selection unit 40 Back end unit (highlighting display means)
41 first scaler unit 42 second scaler unit 43 first image quality correction unit 44 second image quality correction unit 45 superposition unit 46 control unit 50 memory unit (memory)

Claims (11)

In a display device that displays a decoded image in which block distortion is reduced by a deblocking filter,
A specifying unit for specifying a region on the decoded image including a plurality of blocks and having a maximum reduction rate of block distortion by the deblocking filter;
A display device comprising: highlighting means for highlighting an area specified by the specifying means on a display unit. Calculation for calculating a reduction rate of block distortion in each area on the decoded image based on a difference between pixel values before and after the deblocking filter is applied to pixels adjacent to a block boundary included in the area Further comprising means,
The specifying means specifies an area where the reduction rate of the block distortion calculated by the calculating means is maximized;
The display device according to claim 1. The calculation means is
The absolute value of the difference between the pixel values before and after applying the deblocking filter for one pixel of the pixel pairs adjacent via the block boundary included in the region, and the other one of the pixel pairs The absolute value of the difference for the pixel pair is calculated by taking the average of the absolute value of the difference between the pixel values before and after applying the deblocking filter for the pixel of
Calculating a reduction rate of block distortion in each region on the decoded image based on an average of the absolute difference values for each of the plurality of pixel pairs included in the region;
The display device according to claim 2. Calculation for calculating a reduction rate of block distortion in each region on the decoded image based on a parameter associated with a block included in the region and controlling on / off of the deblocking process by the deblocking filter Further comprising means,
The specifying means specifies an area where the reduction rate of the block distortion calculated by the calculating means is maximized;
The display device according to claim 1. The calculation means calculates a reduction rate of block distortion in each region on the decoded image based on an average of the parameters associated with each of a plurality of blocks included in the region.
The display device according to claim 4. The highlighting means enlarges and displays the area specified by the specifying means on the display unit.
The display device according to claim 1, wherein the display device is a display device. The highlighting means extracts the area specified by the specifying means for each of a plurality of consecutive frames, stores the area in a memory, and sets the area for each of the plurality of consecutive frames to a predetermined value. Sequentially enlarged and displayed on the display unit at each time interval,
The display device according to claim 1, wherein: The highlighting means displays the area before the deblocking filter is acted on the display unit together with the area specified by the specifying means for each frame.
The display device according to claim 1, wherein the display device is a display device.   A program for causing a computer to operate as the display device according to any one of claims 1 to 8, wherein the program causes the computer to function as each unit included in the display device.   A computer-readable recording medium in which the program according to claim 9 is recorded. In a display method for displaying a decoded image in which block distortion is reduced by a deblocking filter,
A specifying step for specifying an area on the decoded image including a plurality of blocks, in which the reduction rate of block distortion by the deblocking filter is maximized;
And a highlighting step of highlighting the region identified in the identifying step on the display unit.