Abstract: A method and apparatus for reducing block related artifacts in video are disclosed. A boundary is defined in a video frame between at least two or more sub-blocks where each of the sub-blocks contains a predetermined number of pixels. Pixels adjacent to the boundaries of the sub-blocks may be filtered to reduce blocking artifacts in the video. Pixel video values such as luma and chroma values may be utilized as input values to an anti-block filter. Average mean and average variance of the pixel video values in a sub-block are used to determined when anti-block filtering is applied. Pixels adjacent to the sub-block boundaries are filtered with an anti-block filtering algorithm in the event a predetermined condition is satisfied where the condition may be based upon the calculated average mean and average variance values. The filtering algorithm may include recalculating a pixel video value for pixels adjacent the sub-block boundaries.

Abstract: A method for robust time domain block decoding is disclosed. In one embodiment, the method includes receiving a block of transform domain coefficients, detecting errors in one or more transform domain coefficients, decoding pixel values from the transform domain coefficients, determining a first estimate for each erroneous pixel value, and updating the decoded pixel values.

Abstract: The present invention relates to a method of processing data contained in a digital input image. The data processing method comprises a gradient filter step (GF) of values (Y) of the pixels, which permits to detect (THR) a natural contour area (NC) inside the digital input image. The invention also comprises a step (BAD) of detecting blocking artifacts originating from a block-based coding technique, from a calculation (CT) of a discontinuity value based on values (Y) of a current pixel and of pixels adjacent to said current pixel. The method finally comprises a low-pass filter step (LPF) of the values (Y) of the pixels coming from the artifact blocking detection step (BAD) with the exception of the pixels contained in the natural contour areas (NC) determined by the gradient filter step.

Abstract: A de-convolution process is applied to an MR, CT or other image (25) of a scanned-object (23) to derive the point-spread function (22?) at an object-edge and to pin-point from the mid-point of its full-width-half-maximum FWHM, the location (30) of the true image-edge. With the object-image (25?) overlying the PSF function (22?) in the de-convolution space, sub-pixels which follow location (30) are transferred to before it to re-construct the image-edge (25?) for sharper conformity to the object-edge (23). Sharp definition of image-contour (37) facilitates accurate determination of area and volume of image profiles (35) and their segmentation. The accurate image-edge definition enables viable correction of geometrical distortion in stand-alone MR diagnosis and treatment planning.

Abstract: Reduction of aliasing artifacts along discontinuity edges of a rendered polygon mesh is achieved by overdrawing the edges as antialiased lines. The discontinuity edges are oriented consistently and blended as they approach silhouettes in the mesh to avoid popping at the edge, thereby achieving a temporal smoothness at the silhouettes. This temporal smoothness is balanced with a competing desire to maintain spatial sharpness by utilizing an asymmetric blending technique. To further improve results, the discontinuity edges can be sorted by depth prior to overdrawing them. These processes are effective at reducing the temporal artifact known as “crawling jaggies”.

Abstract: Briefly, in accordance with one embodiment of the invention, a video processing system includes: a video coder. The video coder includes the capability to generate an edge detection map along a predetermined direction for an uncoded frame that is to be coded. Briefly, in accordance with another embodiment of the invention, an article includes: a storage medium having stored thereon instructions capable of being executed by a system that when executed result in: producing an edge detection map along a predetermined direction from the video frame prior to coding; and coding the edge detection map and the video frame. Briefly, in accordance with one more embodiment of the invention, a method of processing a video frame includes: producing an edge detection map along a predetermined direction from the video frame prior to coding; and coding the edge detection map and the video frame.

Abstract: A method for generating an enhanced image includes the steps of: (a) receiving a matrix of pixels representative of an image; (b) generating a gradient image representative of a difference between values of adjacent pixels; (c) calculating a center of mass for each pixel of the gradient image in response to gradient intensity values and location values of neighboring pixels; and (d) generating an enhanced image by modifying intensity values of pixels of the matrix of pixels that are located in a vicinity of local centers of mass in response to intensity values of pixels that are further displaced from the local centers of mass.

Abstract: An image processing apparatus comprises a noise detection means for performing noise detection on an input image; a noise removal means for removing noise from a predetermined region of the input image, on the basis of the result of the noise detection; a counting means for obtaining the ratio of an area targeted for noise removal to the predetermined region of the input image; a statistics calculation means for obtaining the statistics on the ratios obtained by the counting means over a predetermined period of time; an image generation means for generating an image indicating the statistics; and an image composition means for superimposing the image generated by the image generation means on the image outputted from the noise removal means to generate a composite image for display. Therefore, the viewer can easily know how much noise is removed from the predetermined region of the input image, for every predetermined period of time.

Abstract: This invention relates to an image data processing method or the like capable of obtaining a preferable reproduction image based on processed image data even if the image data is short of the unit of block on reading the image data from the memory means in the unit of block. When image data of “M lines×N pixels” written in a memory is read in a unit of block consisting of the predetermined number of pixels and the read image data is subjected to a compression coding process or the like, if data of two lines and data of four pixels per line are short, data of two pixels per line is added to the left end side of the image by using data (1,1) (2,1) . . . (M,1) in the left end side thereof and data of two pixels is added to the right end side of the image by using data (1,N) (2,N) . . . (M,N) in the right end side thereof. Data of one line is added to the upper end side of the image by using data (1,1) (1,2) . . .

Abstract: The present invention relates to a method for eliminating a blocking effect in a compressed video signal signal. The method of the invention includes: the encoding step of eliminating a blocking effect by compensating the motion of a signal compressed in block unit to be transmitted; the decoding step of restoring the motion compensated video signal to the original video signal by reducing the prediction residual between the motion compensated video signal and the original video signal and the blocking effect; and the post-filtering step of performing post-filtering in a blocking elimination filter in order to eliminate a blocking effect and ring effect remained in the compensated signal. The equation for obtaining the original pixel is made simple by eliminating the remaining blocking effect and ring effect using a loop/post filter.

Abstract: A method for post-processing compressed image data for reducing blocking artifacts is suggested, in which a set of primary image data (PID) is decomposed into data sets (IID1, IID2) containing the fine structure of the image with structure being smaller than the blocking artifacts and without the blocking artifacts and structures being larger than or comparable to the blocking artifacts as well as the blocking artifacts, respectively. In the decomposition of the primary image data (PID) a non-linear filtering process (F1) is involved. After decomposition of the primary image data (PID) a filtering process (F3) can be applied to the set of intermediate image data (IID2) containing larger details of the image as well as the blocking artifacts. Therefore, in the process of filtering out the blocking artifacts, the fine structure of the image is not influenced.

Abstract: Ringing artifacts in digital images are predicted by determining a number of pixels of a block of pixels exhibiting luminance exceeding a luminance threshold adequate for detecting a ringing artifact and a number of these higher luminance pixels having sufficient contrast with neighbor pixels to be a likely source of a ringing artifact.

Abstract: A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

Abstract: A motion compensation apparatus to provide block-based motion compensation, and a method thereof. A first motion compensation interpolator calculates a first interpolation pixel by reading a first and a second pixel corresponding to a motion vector of an estimated current block respectively from a current and a previous frame or field. A second motion compensation interpolator calculates a second interpolation pixel by reading a third and a fourth pixel corresponding to a motion vector of peripheral blocks adjacent to the current block respectively from the inputted current and previous frame or field. A candidate interpolation pixel calculator calculates a candidate interpolation pixel by allocating a predetermined weight to the first and the second interpolation pixels, among the current blocks. A motion analyzer analyzes the motion vectors of the current block and the peripheral blocks, and determines discontinuities between the blocks.

Abstract: The present invention relates to a method of measuring video quality. Said method comprises a step of determining (21) at least one reference level (JND) above which visual artifacts become noticeable to a group of subjects, with a corresponding predetermined artifact metric (M), from a set of reference sequences (RS) of digital pictures only comprising a corresponding artifact. The method of measuring video quality also comprises a step of measuring (22) at least one artifact level (L) of the input sequence (IS) with the corresponding predetermined artifact metric (M). It further comprises a step of computing (23) a video quality metric (OQM) of the input sequence from at least one ratio of the artifact level (L) to the reference level (JND) corresponding to a same predetermined artifact metric. Such a method of measuring video quality provides an objective quality metric.

Abstract: A digital image processing determining the extent of blocking and contouring artifacts in a digital image includes the steps of: determining the extent of blocking artifacts using the column and row difference arrays; determining the extent of contouring artifacts based on an estimated DC quantization step size; and, determining a composite artifact measure as a function of the extent of blocking artifacts and extent of contouring artifacts.

Abstract: The invention, in a first aspect, is a method for mitigating edge effects in a decompressed video image. The method comprises first reads an N×N group of pixels defining a vertical edge between two blocks in a video frame row by row into N registers, wherein N is a predetermined number defining the length of a filter. The content of the N registers is then transposed and then filtered in the filter. The filtered content of the N registers is then transposed and stored back from where it was read. In other aspects, the invention is a program storage device encoded with instructions that, when executed by a computer, perform such a method; a computer programmed to perform such a method; and a computing system capable of performing such a method.

Abstract: There is provided a method for automatically set a spatial resolution for an image to be encoded by properties of an image during an encoding process. The method includes the steps of dividing the moving image into blocks and compression encoding the moving image for each of the blocks, decoding an encoded moving image, obtaining a block distortion ratio from a decoded image, and making a resolution decision to select a first resolution lower than a current spatial resolution if the block distortion ratio is greater than a first threshold value or a second resolution higher than the current spatial resolution if the block distortion ratio is smaller than a second threshold value.

Abstract: Embodiments describe a method, apparatus and system for processing images using block based compression. In one embodiment, a method comprises determining whether two blocks are neighboring blocks, determining whether the two neighboring blocks are both subdivided, if the two blocks are neighboring blocks; performing deblocking filtering on one or more edge pixels of the two neighboring blocks, if it is determined that both of the two neighboring blocks are not subdivided.

Abstract: A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

Abstract: A method to remove ringing artifacts from locations near dominant edges of an image reconstructed after compression. The image is decomposed into blocks small enough so that each would contain only one significant edge. A significant edge is tested as to whether it is a dominant edge of the image. If there is no dominant edge, the block is not processed. In the remaining blocks, the exact pixels that include the dominant edges are output without filtering. The direction of the dominant edges is inferred, and then the remaining pixels are filtered with a directional de-ringing filter. The de-ringing filter has a main direction that is perpendicular with the direction of the edge, and thus also with an inherent direction of the ringing artifacts.

Abstract: An image processing apparatus for removing block distortion comprises an area specifying unit 103 for specifying a block distortion area to remove the block distortion therefrom in a reconstructed image decoded from a compressed data, and a block distortion area noise removing unit 104 for removing the noise from the block distortion area.

Abstract: First and second noise detecting circuits detect whether image data output from a signal processing circuit includes noise. If the image data includes noise, first and second noise reducing circuits reduce the noise. An edge extracting circuit extracts edge data from the first image data in which noise has been reduced. An adding circuit adds the edge data and second image data, which has been output by the second noise reducing circuit, and outputs the resultant data. Even though edge enhancement is applied, noise is not enhanced but noise is reduced.

Abstract: In order to remove blocking artefacts from a frame which has been coded by blocks and then decoded, a certain number of pixels (n) is selected for examination from both sides of the block boundary (30). The number of pixels selected for examination depends on the image content of the frame in the environment of the block boundary, particularly on the difference of the pixel values across the block boundary (30) and the size of the quantization step of the transformation coefficients used in the transformation coding of the blocks.

Abstract: An improved block noise elimination method is provided, which uses one-dimensional pixel vectors made of pixel rows or columns across two neighboring blocks to analyze blocky noise residing across the neighboring blocks. The blocky noise in each pixel-vector is modeled as shape vector multiplied by boundary discontinuity. The shape vector, varying with local image activity, is estimated by Minimum Mean Squared Error (MMSE) approach. Depending upon the shape vector, the corresponding blocky noise is eliminated in postprocessing of decoded images so that encoded images may be restored to their original images.

Abstract: A vertical HPF and a horizontal HPF receive a video signal 101, and extract only a high frequency component in the vertical/horizontal directions, respectively. Absolute value taking parts take an absolute value of the high frequency components, respectively, and change their values to positive values. A horizontal accumulating/adding part and a vertical accumulating/adding part accumulate/add an input signal so as to output a vertical one-dimensional signal and a horizontal one-dimensional signal, respectively, each periodically having a peak value in the respective vertical and horizontal directions. A horizontal peak detecting part detects a horizontal peak position according to the horizontal one-dimensional signal. A vertical peak detecting part detects a vertical peak position according to the vertical one-dimensional signal and identifies a format thereof.

Abstract: In a method for removing artifacts in a digital image that has been decoded from a compressed representation of the image, the pixels of the digital image are segmented into low detail pixels, high detail pixels, and boundary pixels, and then a single non-linear filtering method, such as a sigma filtering method, is applied to each pixel in the digital image. By selecting separate filter parameters for the low detail, high detail, and boundary pixels, the removal of artifacts is improved over prior methods.

Abstract: A method (200) and decoder system (100) for reducing quantization effects or ringing artifacts imposed upon decoded image of hybrid block based coding schemes such as MEPG and H 261. The system (100), in use, and method (200) receive (220) decoded image decoded blocks that were decoded from transform coded blocks quatized by a selected quantization parameter. The system (100) and method (200) then analyze (230) selected pixel values of selected pixels with neighboring pixel values of associated neighboring pixels in the decoded blocks to determine difference values for each of the selected pixels. Potential object edges, of the decoded image represented by the decoded blocks, are then detected (240) to identify the selected pixels as edge pixels, the detecting is effected by comparing the difference values with selected threshold values that are determined with respect to the selected quantization parameter associated with the blocks.

Abstract: A de-blocking method and apparatus in which a block classifier determines whether the received decoded image is a planar surface or a complex surface. A first correction value calculator calculates correction values for block boundary pixels using a first filtering coefficient when the decoded image is a planar surface, an interpolator provides first correction values for pixels on the block boundary, and a second correction value calculator calculates second correction values for some block boundary pixels using a second filtering coefficient when the decoded image is a complex surface. A corrector provides a corrected image by correcting the received decoded image using the first correction values when the received decoded image is a planar surface, or using the second correction values when the received decoded image is a complex surface.

Abstract: In order to remove blocking artifacts from a frame which has been coded by blocks and then decoded, a certain number of pixels (n) is selected for examination from both sides of the block boundary (30). The number of pixels selected for examination depends on the image content of the frame in the environment of the block boundary, particularly on the difference of the pixel values across the block boundary (30) and the size of the quantization step of the transformation coefficients used in the transformation coding of the blocks.

Abstract: A video encoding method and apparatus is shown wherein image information is represented as a plurality of pixels, the pixels are organized into blocks, pixels transposition is performed on image information at the boundaries of the blocks, the blocks are transform coded and quantized. Pixel transposition involves transposition of alternate pixels at the boundaries of blocks with pixels of neighboring blocks found in a pre-determined direction. The pre-determined direction may be fixed by a system or may be applied on an image by image basis. In the event that the pre-determined direction is not established by a system, a pixel transposition circuit includes a transposition keyword in the output bit stream which is used by a decoded to determine the direction of pixel transposition.

Abstract: A method for reducing block artifacts between image blocks of a decompressed image is provided. The method initiates with selecting a set of pixel positions corresponding to pixels proximate to a border between the image blocks. Then, an amount of additional frames to be inserted when displaying the decompressed image is determined. Next, a pixel value associated with each pixel of the set of pixels proximate to the border is modified for each of the additional frames. Then, an original frame and the additional frames are displayed in an alternating mode such that block artifacts between the image blocks are visually reduced. A computer readable media, an integrated circuit and a device enabled to reduce blocking artifacts are also provided.

Abstract: A method to remove ringing artifacts from locations near dominant edges of an image reconstructed after compression. The image is decomposed into blocks small enough so that each would contain only one significant edge. A significant edge is tested as to whether it is a dominant edge of the image. If there is no dominant edge, the block is not processed. In the remaining blocks, the exact pixels that include the dominant edges are output without filtering. The direction of the dominant edges is inferred, and then the remaining pixels are filtered with a directional de-ringing filter. The de-ringing filter has a main direction that is aligned with the direction of the edge, and thus also with an inherent direction of the ringing artifacts.

Abstract: A method for determine blurring in a test video sequence due to video processing includes detecting blocks within each frame of the test video sequence that have valid image edges. An edge point within each valid image edge block is selected and a series of points defining an edge profile in the block along a line normal to the valid image edge at each edge point is defined from an enhanced edge map in which video processing blockiness artifacts have been removed. From the edge profile a blurring value is estimated for each frame or group of frames within the test video sequence. Additionally a reference blurring value may be derived from a reference video sequence corresponding to the test video sequence, which reference blurring value may be generated at a source of the reference video sequence and transmitted with the test video sequence to a receiver or may be generated at the receiver.

Abstract: A formation method of a two-dimensional code is characterized by including the steps of: storing each cell having a bright pattern or a dark pattern as 0 or 1 in a two-dimensional array after reading a bit map file; calculating a number of round dots contained in a cell from the size of one cell to be laser-marked and a processed diameter of a round dot formed by a laser beam according to material processed; obtaining a processed area from the two-dimensional array stored and the size of one cell; setting a plurality of cell frames in a checked pattern with this center point as a base; arranging the round dots in equal intervals in the cell frames; storing in memory the coordinates of beam spots corresponding to the respective round dots arranged; and outputting process data stored in this memory to a laser marker and performing laser-marking.

Abstract: The present invention relates to a method and system for controlling the quality of video data by selecting the optimal quantization parameter during encoding. The system is configured to perform quantization for one or more macroblocks using a different range of step sizes, then the kurtosis for the respective quantized data is performed to determine the macroblock and the corresponding quantization step size that yields the highest kurtosis value. The quantization step size that generates the highest kurtosis value is selected to the blocks of input-video data during encoding.

Abstract: A wavelet encoding method and apparatus and a wavelet decoding method and apparatus for pictures. A input picture is split into plural tile pictures and wavelet transform is applied to input pictures on the tile picture basis to effect the encoding. For wavelet transform, pixels lying on the outer side of a given tile picture are symmetrically expanded and convolved. This enables marked memory capacity reduction, while eliminating constraint conditions for the number of times of wavelet splitting.

Abstract: There is provided an image signal distortion removal apparatus which performs a distortion removal process for removing distortion attendant on decoding of an image signal, and vertical and horizontal filtering processes for the image signal, wherein a control circuit for performing the distortion removal process and the vertical filter process in block units is introduced. Thereby, the processing amount in the distortion removal process, which increases with an increase in the number of taps of the vertical filter, can be reduced.

Abstract: An encoder, decoder, and corresponding method are disclosed for encoding pixel data as a plurality of block transform coefficients and decoding encoded block transform coefficients to provide reconstructed pixel data, the encoder and/or decoder includes a conditional deblocking filter for filtering only block transitions meeting pre-selected pixel brightness level criteria, where the conditional deblocking filter method includes receiving at least one first pixel adjacent to a block transition, providing a signal indicative of the brightness of the at least one first pixel, comparing the brightness signal with at least one of an upper brightness threshold and a lower brightness threshold, and conditionally filtering a plurality of adjacent pixels including the first pixel at the block transition in response to the brightness comparison.

Abstract: A digital image processing method determines the extent of blocking artifacts in a digital image by first forming a column difference image and averaging the values in the columns in the column difference image to produce a column difference array. The average of the values in the column difference array that are separated by one block width are computed to produce a block averaged column difference array. Then, the peak value in the block averaged column difference array is located, and the mean value of the block averaged column difference array (excluding the peak value) is calculated to produce a column base value, and the ratio between the peak value and the base value are computed to produce a column ratio. The foregoing steps are repeated in the row direction to produce a row ratio. Finally, the column and row ratios are employed as a measure of the extent of blocking artifacts in the digital image.

Abstract: An digital image input, possibly being either pre-compressed or decompressed, is enhanced; its edges are preserved while any compression artifacts, like blocking and ringing, are simultaneously reduced. The enhancement method enhances images with luminance and chrominance functions, incompletely defined or undefined, on a set of pixels so that the missing information is extrapolated while the image is simultaneously enhanced. The method consists of up to three integrated sub-processes: the image sharpening flow; the de-quantization filtering; and the means of control of the local rate of flow. The image sharpening flow is an iterative nonlinear filtering schema intertwining a local median filter and a suitably chosen linear filter. A local geometric control mechanism allows selective application and adaptation of an algorithm allowing selective removal of local artifacts.

Abstract: A digital image processing method reduces noise and blocking artifacts in a digital image by first converting the RGB values of the digital image pixels to Y, Cb and Cr components, then detecting the block boundaries in the Y, Cb and Cr image components, and estimating the noise in the Y, Cb and Cr image components. One or more noise tables are constructed for the Y, Cb and Cr image components. An adaptive Huber-Markov-random-field-model-based filter (HMRF) is applied to the Y, Cb and Cr image components, wherein the adaptive feature of the HMRF employs the detected block boundaries and the noise tables to produce filtered Y, Cb and Cr image components. Finally, the filtered Y, Cb and Cr image components are converted to RGB components.

Abstract: The invention concerns a method for detecting geological discontinuity in an environment using an optical flow. The method includes the steps of selecting in the seismic block a section containing at least one discontinuity. The section constitutes a seismic image. The method includes computing a rough optical flow on the seismic image to obtain a first representation of an optical flow wherein the discontinuity constitutes a moving front. The method also includes smoothing, by a non-supervised dynamic cluster process, the optical flow representation so as to obtain a second optical flow representation wherein the discontinuity shows accentuated contrasts.

Abstract: A signal adaptive filtering method for reducing blocking effect and ringing noise. a signal adaptive filter, and a computer readable medium. The signal adaptive filtering method capable of reducing blocking effect and ringing noise of image data when a frame is composed of blocks of a predetermined size includes the steps of: (a) generating blocking information for reducing the blocking effect and ringing information for reducing the ringing noise, from coefficients of predetermined pixels of the upper and left boundary regions of the data block when a frame obtained by deconstructing a bitstream image data for inverse quantization is an intraframe; and (b) adaptively filtering the image data passed through inverse quantization and inverse discrete cosine transform according to the generated blocking information and ringing information. Therefore, the blocking effect and ringing noise can be eliminated from the image restored from the block-based image, thereby enhancing the image restored from compression.

Abstract: The present invention relates to a method of processing digital images comprising pixel blocks, said method comprising a step of detecting blocking artifacts (41) between two adjacent blocks (Bj,bk), and a step of filtering (43) the pair of adjacent blocks. The method according to the invention further comprises a filter decision step (42) based on a comparison between luminance values of the pixels of the two adjacent blocks and a reference function representing a difference of minimum luminance values that can be seen by an observer as a function of an average luminance area of the image in order to determine whether a difference of luminance between the blocks is either or not visible to an observer.

Abstract: An apparatus and a method is provided for enhancing a digital image comprised of pixels by adaptively sharpening the pixels and clipping the numerical values of the sharpened edge pixels so as to fall between the smallest unsharpened numerical value and the greatest unsharpened numerical value, respectively, of the pixels located within a neighborhood of the pixels. Pixels which are located on an edge are sharpened in the direction perpendicular to the edge. The threshold value used to ascertain the presence of an edge and sharpening parameter used to control the degree of sharpening can be adaptively controlled by the zoom ratio. The apparatus of the invention is particularly suited for an electronic set-top video camera.

Abstract: A method of detecting blocking artifacts in digital video pictures, includes a step of filtering (GF) a digital input signal (x) using a gradient filter for providing at least one filtered signal, and a step of calculating (CALC) a block level metric (BM) for processing the filtered signal(s) to identify and count blocking artifacts as a function of their position in a grid. If the block level metric (BM) is lower than a threshold, the picture has either not been encoded using a block-based processing, or has been encoded in a seamless way. In the opposite case, the picture has been encoded using a block-based processing in a non-seamless way and corrective actions, such as a post-processing (PP), can be taken.

Abstract: A filter reduces artifacts, such as grid noise and staircase noise, in block-coded digital images with image block boundaries. The type of filtering is determined after an estimation of the image global metrics and local metrics. For areas of the image near grid noise, the filter performs low pass filtering. For image fine details, such as edges and texture, no filtering is performed so that masking is avoided. The filter operates in intra-field mode and uses a fuzzy logic process, pixel deltas, and dual ramp generators to determine the horizontal and vertical length of a processing window surrounding an image block boundary.

Abstract: A method and apparatus to remove a block effect and a ring effect appearing in a compression-coded image is disclosed. The present invention is especially applicable to an image compression-coded at a low bit rate. In particular, the present invention includes a variety of masks for the removal of the block/ring effect. Thus, one mask is select for a pixel to be filtered. Moreover, candidate pixels to be averaged with the pixel to be filtered is selected from the pixels of the selected mask to better maintain the details of the image, and a weight is applied to improve the calculation speed of the averaging operation. More particularly, the masks according to the present invention have longer tabs toward adjacent blocks at boundaries of the given block to remove the block and ring effect.

Abstract: This invention can suppress overshoot/undershoot, and can maintain the improvement effect of the leading edge of an edge portion. For this purpose, a second derivative signal generator (1) generates a second derivative signal (s5) on the basis of time-serially input three successive pixels. A second derivative signal suppression unit (2) generates a signal (s8) obtained by suppressing the second derivative signal, and a signal (s9) indicating the sign of the second derivative signal. The absolute values of the differences between the pixel of interest, and its neighboring pixels are computed, and a smaller one of the absolute values is selected as a signal (s14) by a minimum value selection circuit (18). By multiplying the obtained signals (s8, s9, s14) by a multiplier (19), an edge-emphasizing signal (s15) is generated. The edge-emphasizing signal (s15) is added to the signal of the pixel of interest by an adder (20), thus obtaining an edge-emphasized signal s16.