JP2007174403A - Video processing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an excellent video image while reducing a load to a CPU. <P>SOLUTION: A video processing apparatus of the present invention comprises a deblocking processing section 14 which detects a position of block noise generation for each pixel block from video data decoded by a decode processing section 12, performs reduction or elimination processing on block noise at that position and storing position information of a pixel at the block noise generation position in a memory, and an edge emphasizing processing section for reading the position information of the block noise generation position from the memory and performing edge emphasizing processing upon video data within a range excluding that position. Thus, when adjusting image quality by decoding compressed video data, edge emphasizing processing is not performed on a position where block noise is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a video processing apparatus and a video processing method, for example.

  In general, a video recording / reproducing apparatus that reproduces a compressed video such as Moving Picture Expert Group (hereinafter referred to as MPEG), that is, a video processing apparatus, blocks noise when decoding compressed video digital data. Reduction processing and image quality adjustment processing.

  As a prior art of this type of image processing, there is a technology that selectively performs block noise reduction processing and image quality adjustment processing using compression-related parameters (see, for example, Patent Document 1).

  The technique of the above-mentioned document 1 removes distortion by smoothing processing for block distortion that occurs around the block boundary, and performs edge enhancement processing for edges on the block boundary, thereby providing a sharp and distortion-free image. Is what you get.

In this case, switching between smoothing processing and edge enhancement processing is switched based on the level difference of pixels near the block boundary.
JP-A-9-27955

  However, conventionally, switching between the smoothing process and the edge enhancement process is performed based on a preset parameter, which may cause unevenness in image quality.

  Also, when the smoothing process and the edge emphasis process are overlapped over the entire screen or within a certain range instead of switching the process, the CPU is used to process heavy data such as video data with a computer. There is a problem that load is applied.

  The present invention has been made to solve such a problem. When image quality adjustment is performed by decoding compressed video data, a location where block noise has been reduced is actually detected, and the location is determined. An object of the present invention is to provide a video processing apparatus and a video processing method capable of obtaining a good image quality while reducing the load on the CPU by not performing the edge enhancement processing.

  In order to achieve the above object, a video processing apparatus according to the present invention includes a decoding processing unit that decodes compressed video data, a memory that can store information, and video data decoded by the decoding processing unit. A block noise occurrence location for each pixel block is detected and block noise is reduced or removed at that location, and a deblocking processing unit that stores pixel location information of the block noise occurrence location in the memory; and An edge enhancement processing unit that reads position information of a block noise occurrence location from a memory and performs edge enhancement processing on video data in a range excluding the location is provided.

According to another aspect of the present invention, there is provided a video processing method in a video processing apparatus that reproduces while storing compressed video data in a memory. The video processing apparatus decodes the compressed video data; From the video data, the video processing device detects a block noise occurrence location for each pixel block and performs block noise reduction or removal processing at that location, and stores pixel location information of the block noise occurrence location in the memory And a step in which the video processing apparatus reads position information of a block noise occurrence location from the memory and performs edge enhancement processing on video data in a range excluding the location.

  In the present invention, when the compressed video data is decoded and image quality adjustment is performed, the block noise occurrence location is detected and the block noise is removed. In this case, since block noise reduction processing is performed in accordance with the level difference between the blocks where the detected block noise occurs, the affected area of the block noise, that is, the position of the pixel where the block noise has occurred is always detected. .

  Therefore, after performing block noise reduction processing by image quality adjustment processing, it is determined whether or not to perform edge enhancement processing based on the positional information of the pixel where block noise occurs, and the edge enhancement processing is controlled.

  In other words, by actually detecting the part where the block noise is reduced and not performing the edge enhancement processing for that part, the part where the block noise actually occurs is partially (local) according to the degree. Therefore, it is possible to obtain a good image quality when reproducing video data. In addition to this, by not performing computations on the portions that do not require processing, unnecessary computations can be prevented. For example, when video is reproduced by software processing, the load on the CPU can be reduced.

  As described above, according to the present invention, when image quality adjustment is performed by decoding compressed video data, the load on the CPU is reduced by not performing edge emphasis processing on the portion where the block noise is reduced. It is possible to obtain a good image quality while reducing the image quality.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a video processing apparatus according to one embodiment of the present invention.

  As shown in FIG. 1, the video processing apparatus according to this embodiment includes a compressed video data acquisition unit 11, a decoding processing unit 12, a deblocking processing unit 14, an edge enhancement processing unit 16, and a pixel position information storage unit 17. . Each of these units may be configured by hardware or software.

  This video processing apparatus is a video recording / playback apparatus that records and / or plays back video in a compressed format such as Moving Picture Expert Group (hereinafter referred to as MPEG), for example, and is referred to as a central processing unit (hereinafter referred to as CPU). ), A computer including a memory, a hard disk device, an optical disk drive device, a monitor, and the like.

  The compressed video data acquisition unit 11 acquires compressed video digital data such as MPEG format video data from an optical disk set in the optical disk drive. The decode processing unit 12 decodes the compressed digital data acquired by the compressed video data acquisition unit 11 and inputs the decoded digital data to the deblocking processing unit 14 as video data 13.

  The deblocking processing unit 14 detects the position of block noise in the video data generated by the compression, performs block noise reduction processing on the pixel at that position, and outputs it to the edge enhancement processing unit 16.

  The deblocking processing unit 14 detects a block noise occurrence location for each pixel block from the video data 13 decoded by the decode processing unit 12 and performs block noise reduction or removal processing on the location, and generates block noise. The position information of the pixel at the location is stored in the memory.

  The deblocking processing unit 14 checks the stepped state between the blocks where the detected block noise occurs using a plurality of threshold values, and performs block noise reduction processing according to the stepped state.

  The deblocking processing unit 14 determines the block noise occurrence location for each pixel block, the first block noise influence range (block noise influence range (wide)) and the second block noise influence range (block noise influence range ( Narrow)) and the position information of the pixel of the block noise occurrence location divided into the range is stored in the memory.

  The pixel position information storage unit 17 is realized by a memory or a hard disk device. The pixel position information storage unit 17 stores pixel position information when the deblocking processing unit 14 detects block noise.

  As position information, for example, a block number, the number of pixels for each area (wide / narrow) subjected to block noise reduction processing, a line number, and the like are stored.

  Further, input video data is sequentially buffered in an area of the memory other than the pixel position information storage unit 17 and sequentially read out during image quality adjustment (such as edge enhancement).

  In addition, a plurality of threshold values, for example, a first threshold value, a second threshold value, and a third threshold value are stored in advance in the memory as determination data. The first threshold is a value for determining the lower limit of the block noise. If the noise is smaller than this value, noise reduction is unnecessary.

  The second threshold is a value for determining the upper limit of noise, and a value greater than this value can be determined not as noise but as a step in the video itself. The first threshold value and the second threshold value have a relationship of first threshold value <second threshold value. The third threshold is a value for determining a change in video data.

  The edge enhancement processing unit 16 performs edge enhancement processing using the position information of the pixel at the block noise occurrence location for each influence range read from the memory.

  Specifically, the edge enhancement processing unit 16 performs edge enhancement processing on the edge portion only for pixels excluding the vicinity of the corresponding pixel using the pixel position information stored in the pixel position information storage unit 17. That is, the edge enhancement processing unit 16 reads the position information of the block noise occurrence location from the memory, and performs the edge enhancement processing on the video data in the range excluding the location.

  Next, the operation of this video processing apparatus will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the video processing apparatus of FIG.

  In the case of this video processing apparatus, the compressed video data acquisition unit 11 acquires compressed video digital data and outputs it to the decoding processing unit 12.

  The decode processing unit 12 performs the decoding process on the compressed video data input from the compressed video data acquisition unit 11 (S101), thereby generating the video data 13.

  The deblocking processing unit 14 searches for the block noise occurrence position for the decoded video data 13 (S102).

  Next, the deblocking processing unit 14 performs block noise reduction processing based on the search result of the block noise occurrence position (S103), thereby generating video data 15 with reduced block noise, and an edge enhancement processing unit. 16 is output.

  Moreover, the deblocking process part 14 memorize | stores the positional information on the pixel which performed the block noise reduction process in the pixel position information storage part 17 (S104).

  The edge enhancement processing unit 16 performs edge enhancement processing on the video data input from the deblocking processing unit 14.

  In this case, the edge emphasis processing unit 16 first reads out the position information of the pixel subjected to the block noise reduction process from the pixel position information storage unit 17, detects the block noise reduction position from the position information (S105), Edge enhancement processing is performed only for pixels in the vicinity of which are not affected by block noise (S106).

  By performing edge enhancement processing only for pixels that are not affected by block noise in this way, edge enhancement processing is not performed at locations where block noise occurs, so that noise is noticeable by edge enhancement processing. Can be prevented.

  Here, the influence of pixels and block noise will be described with reference to FIGS. In the figure, the solid line A is the waveform of the video signal before block noise reduction, and the dotted line B is the waveform of the video signal after reduction processing.

  As shown in FIG. 3, since the edge of the image itself and the high frequency component do not exist near the block boundary line, a filter process for reducing the block step is performed in a range P having a certain width, It becomes a waveform. At this time, since the influence of the block noise can be considered to have spread to the range of the dotted line B, the pixel subjected to the edge enhancement processing is a range excluding the dotted line B.

  In FIG. 4, since the edge E exists in the vicinity of the block boundary, the block noise reduction processing is performed for a range that avoids this edge portion, and therefore is narrower than the block noise influence range P shown in FIG. Block noise reduction processing is performed in the block noise influence range Q.

  After the block noise reduction processing is performed by the deblocking processing unit 14, the edge enhancement processing unit 16 performs edge enhancement processing on pixels in a range excluding the range (part) of the dotted line B. In addition, the edge emphasis processing is also applied to the portion of the edge E shown in FIG.

  As described above, it is possible to appropriately perform the edge enhancement processing corresponding to the situation where the block noise is reduced.

  In addition, since unnecessary processing is not required, the load on the CPU can be reduced when video is reproduced by software processing by a computer.

  Specifically, for example, in a system (software decoding system) that processes video digital data on a computer by software processing that requires CPU power, the video digital data subjected to block noise reduction processing is temporarily stored in a memory. Only the video digital data of the pixels that need the edge enhancement processing is read from the memory and the edge enhancement processing is performed, so that waste of CPU power can be prevented.

  As described above, according to the video processing device of this embodiment, when performing edge enhancement processing on video data on which block noise reduction has been performed, a location where block noise reduction has actually been performed is detected, and Improve the playback image quality of the video and play a good video by applying edge enhancement processing to the part excluding the part, but not performing wasteful processing such as noise enhancement for the block noise reduction part. Can do. In addition, when the image quality adjustment process is executed by software processing on a computer, the calculation amount of the CPU can be reduced.

  The detailed operation of this video processing apparatus will be described below with reference to FIGS. First, the block noise occurrence position detection operation and the position storage operation by the deblocking processing unit 14 will be described with reference to FIG.

  In this case, when a video signal is input to the deblocking processing unit 14, the deblocking processing unit 14 checks the level difference of the video signal at the block boundary (S201 in FIG. 5).

  Then, the deblocking processing unit 14 compares the checked level difference of the video signal with a preset first threshold value (S201), and if the level difference is smaller than the first threshold value (Yes in S202), there is no block noise. (S203), and block noise reduction processing is not performed for that portion.

  On the other hand, as a result of comparing the level difference of the video signal at the block boundary with the first threshold value, if the level difference is greater than or equal to the first threshold value (No in S202), the deblocking processing unit 14 presets the level difference of the examined video signal. Is compared with the second threshold value (S204), and if the step of the video signal is larger than the second threshold value (Yes in S204), it is determined that the step is not a block noise but a video step (S205). Noise reduction processing is not performed.

  Also, as a result of comparing the step of the video signal at the block boundary with the second threshold, if the step of the video signal is smaller than the second threshold (No in S204), the deblocking processing unit 14 generates block noise. (S206), the change in the video data near the boundary in each block is examined (S207).

  The deblocking processing unit 14 compares the examined change value of the video data with a preset third threshold value (S208).

  As a result of this comparison, when the change value of the examined video data is smaller than a preset third threshold value, the deblocking processing unit 14 determines that the signal in the block is flat, A step is reduced by applying a filter (S209).

  After reducing the step between the blocks, the deblocking processing unit 14 stores the processed area in the pixel position information storage unit 17 as a reduced position (wide) (S210).

  Further, as a result of comparing the examined change value of the video data with a preset third threshold value, when the examined change value of the video data is equal to or greater than the preset third threshold value, the deblocking processing unit 14 Determines that the signal in the block is undulating, and applies a narrow filter to reduce the step between the blocks (S211).

  After reducing the step between blocks, the deblocking processing unit 14 stores the processed area in the pixel position information storage unit 17 as a reduced position (narrow) (S212).

  Next, the edge enhancement processing operation in the edge enhancement processing unit 16 will be described with reference to FIG. In this case, as shown in FIG. 6, the edge enhancement processing unit 16 compares the coordinates of the processed image position and the block reduction position (wide) on the screen, and the relationship between the processed image position and the block noise reduction position (wide). (S301).

  When the processed image position matches the block noise reduction position (wide) (No in S302), block noise usually occurs in the vicinity of the image portion of the image at the block noise reduction position (wide) as well. The edge enhancement processing unit 16 moves the next processing image position by the block noise reduction position (wide) (S303), and the processing image position and the block noise reduction position again at that position. Check the positional relationship with.

  When the processed image position does not match the block noise reduction position (wide) (Yes in S302), the edge enhancement processing unit 16 converts the plurality of video data buffered in the memory to the block noise reduction position (wide). Read in order until it does not occur. In the computer, since it is more efficient to process the data in a batch, the calculation is performed collectively using a SIMD (Single Instruction Multiple Data) instruction or the like.

  Further, the edge enhancement processing unit 16 compares the coordinates of the processed image position on the screen with the block reduced position (narrow), and examines the relationship between the processed image position and the block noise reduced position (narrow).

  If the processed image position does not match the block noise reduction position (narrow) (Yes in S305), the edge enhancement processing unit 16 obtains image data for edge enhancement by calculation (S306).

  Subsequently, the edge enhancement processing unit 16 performs edge enhancement by adding video data for edge enhancement obtained by calculation to the original video data.

  On the other hand, as a result of comparing the coordinates of the processed image position and the block reduction position (narrow) on the screen, if the processed image position matches the block noise reduction position (narrow) (No in S305), the edge enhancement processing unit 16 The image at that position is output as it is without edge enhancement (S308).

  Hereinafter, a video processing apparatus according to another embodiment will be described with reference to FIGS. As shown in FIG. 7, the video processing apparatus of this embodiment includes a compressed video data acquisition unit 11, a decoding processing unit 12, a deblocking processing unit 14, an edge enhancement processing unit 16, a pixel position information storage unit 17, and a scaler processing unit. 18 is provided.

  That is, in this embodiment, a scaler processing unit 18 is added to the video processing apparatus shown in FIG. Since the processing up to the deblocking processing unit 14 is the same as that of the video processing apparatus shown in FIG. 1, the description of the processing up to that is omitted.

  Video data 15 that is an output of the deblocking processing unit 14 is input to the scaler processing unit 18. The scaler processing unit 18 performs a process of expanding the screen size of the input video data 15 to a screen size having a preset expansion rate.

  That is, the scaler processing unit 18 performs a process of expanding / contracting (expanding or shortening) the display size of the video data input to the edge enhancement processing unit 16 to a display size having a preset expansion rate, and a pixel position information storage unit. 17 has a function of changing the position information of the pixel at the block noise occurrence location stored in 17 by the amount changed by the expansion / contraction (extension or shortening) process.

  In the case of the video processing apparatus of this embodiment, when the video data 15 is input from the deblocking processing unit 14, the scaler processing unit 18 sets the screen size of the input video data 15 to a screen size with a preset expansion rate. Process to expand to

  In this decompression process, the scaler processing unit 18 changes the block boundary position by the scaler process (S401 in FIG. 8). For example, a process of changing an image with an angle of view of 4: 3 to an image with an angle of view of 16: 9 is performed.

  Further, the scaler processing unit 18 changes the range of the block noise reduction position (wide) and the block noise reduction position (narrow) by the scaler processing (S402).

  Then, the scaler processing unit 18 outputs the video data 20 after the decompression process to the edge enhancement processing unit 16.

  On the other hand, the pixel position information detected as a block noise occurrence location by the deblocking processing unit 14 is stored in the pixel position information storage unit 17.

  The position change processing unit 19 reads the pixel position information from the pixel position information storage unit 17 and changes the read pixel position information to the pixel position information 21 corresponding to the expansion rate at which the screen size is expanded by the scaler processing unit 18. . Then, the position change processing unit 19 outputs the changed pixel position information 21 that has been changed to the edge enhancement processing unit 16.

  The edge enhancement processing unit 16 uses the input changed pixel position information 21 to perform edge enhancement processing on edge portions only for pixels excluding the vicinity of the corresponding pixel.

  That is, the edge enhancement processing unit 16 performs edge enhancement processing on the edge portion of the block excluding the vicinity of the corresponding pixel in which block noise has been reduced using the changed block noise reduction position information (S403).

  As described above, according to the video processing apparatus of this embodiment, even when the screen size is expanded by the scaler processing unit 18, the edge enhancement processing for the edge portion is performed only on the pixels excluding the portion where the block noise is generated. Do not perform edge enhancement processing for areas where block noise occurs, so that edge enhancement processing that has the opposite effect of making noise stand out even when changing the screen size is prevented Can do.

It is a figure which shows the structure of the video processing apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the video processing apparatus of FIG. It is a figure which shows the waveform of a video signal at the time of performing a block noise reduction process with respect to a wide block noise influence range in a video processing apparatus. It is a figure which shows the waveform of a video signal at the time of performing a block noise reduction process with respect to a narrow block noise influence range in a video processing apparatus. 5 is a flowchart showing block noise position detection processing and pixel position storage processing in the video processing apparatus. 5 is a flowchart showing edge enhancement processing in the video processing apparatus. It is a figure which shows the structure of the video processing apparatus of other embodiment. 8 is a flowchart showing an operation from a scaler process to an edge enhancement process in the video processing apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Compressed video data acquisition part, 12 ... Decoding processing part, 13 ... Video data, 14 ... Deblocking processing part, 15 ... Video data, 16 ... Edge emphasis processing part, 16 ... Edge emphasis processing part, 17 ... Pixel position information Storage unit, 18 ... scaler processing unit, 19 ... position change processing unit, 20 ... video data, 21 ... changed pixel position information.

Claims (5)

A decoding processing unit for decoding the compressed video data;
A memory capable of storing information;
From the video data decoded by the decoding processing unit, a block noise occurrence location for each pixel block is detected, and block noise reduction or removal processing is performed at that location, and pixel position information of the block noise occurrence location is A deblocking processing unit stored in a memory;
An image processing apparatus comprising: an edge enhancement processing unit that reads position information of a block noise occurrence location from the memory and performs edge enhancement processing on video data in a range excluding the location. The deblocking processing unit
An image processing apparatus characterized in that a step state between blocks at a detected location of block noise is examined using a plurality of threshold values, and block noise reduction processing is performed according to the step state. The deblocking processing unit
The block noise occurrence location for each pixel block is stored in the memory, the pixel location information of the block noise occurrence location divided into the influence range of the first block noise and the influence range of the second block noise,
The edge enhancement processing unit
An image processing apparatus, wherein edge enhancement processing is performed using pixel position information of a block noise occurrence location for each influence range read from the memory.   Performs processing to expand and contract the display size of the video data input to the edge enhancement processing unit to a display size with a preset expansion rate, and expands and contracts the position information of the pixel of the block noise occurrence location stored in the memory A video processing apparatus, further comprising a scaler processing unit that changes the amount changed in step (b). In a video processing method in a video processing apparatus that reproduces while storing compressed video data in a memory,
The video processing device decoding the compressed video data;
From the decoded video data, the video processing device detects a block noise occurrence location for each pixel block, and performs block noise reduction or removal processing at that location, and the pixel location information of the block noise occurrence location Storing in memory;
A video processing method comprising: reading out position information of a block noise occurrence location from the memory, and performing an edge enhancement process on video data in a range excluding the location.

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