Abstract: Images can be coded based on filters defined by filter coefficients or weights assigned to previously decoded pixel values of nearby lines. The filter coefficients can be selected based on evaluation of a set of predetermined filters, or filters can be adaptively generated and then evaluated. The filters generally are based on pixel values in previous rows or columns, but not values in the current row or column. In some examples, filters are adaptively generated pixel by pixel, or portions of previous rows, columns, or previously decoded portions of the current row or columns are used to provide line templates. A filter is generally selected to reduce coding error based on a least square difference between the current value and a prediction.

Abstract: An image coding device including: an edge detecting section configured to perform edge detection using an image signal of a reference image for a coding object block; a transform block setting section configured to set transform blocks by dividing the coding object block such that a boundary between the blocks after division does not include an edge on a basis of a result of the edge detection; and a coding processing section configured to generate coded data by performing processing including an orthogonal transform of each of the transform blocks.

Abstract: An image processing device includes: a plurality of encoding units that encode image data; a shared memory that stores reference image data which is used for encoding performed by each of the plurality of encoding units; and a control unit that secures an encoding unit from the plurality of encoding units, which is made to encode an intra-frame prediction encoded image and a forward prediction encoded image by priority, and that makes an encoding unit, which is not used to encode the intra-frame prediction encoded image or the forward prediction encoded image, encode a bidirectional prediction encoded image, using reference image data stored in the shared memory during a period where the secured encoding unit does not perform the encoding.

Abstract: In the disclosed multi-view image encoding/decoding method in which a frame to be encoded/decoded is divided and encoding/decoding is done to each region, first, a prediction image is generated not only for the region to be processed, but also for the already encoded/decoded regions neighboring to the region to be processed. The prediction image is generated using the same prediction method for both kinds of regions. Next, correction parameters for correcting illumination and color mismatches are estimated from the prediction image and decoded image of the neighboring regions. At this time, the estimated correction parameters can be obtained even at the decoding side, therefore, encoding them is unnecessary. Thus, by using the estimated correction parameters to correct the predicted image that was generated for the region to be processed, a corrected predicted image that can be actually used is generated.

Abstract: A Method and apparatus for encoding and decoding a multi-view image are provided. The method of encoding a multi-view image includes determining whether each of pictures included in multi-view image sequences is a reference picture referred to by other pictures included in the multi-view image sequences for inter-view prediction, and encoding the pictures using at least one of inter-view prediction and temporal prediction based on the determination result, thereby efficiently encoding and decoding the multi-view image at high speed.

Abstract: An apparatus for use in image processing is set forth that comprises a pixel processor, context memory, and a context memory controller. The pixel processor is adapted to execute a pixel processing operation on a target pixel using a context of the target pixel. The context memory is adapted to store context values associated with the target pixel. The context memory controller may be adapted to control communication of context values between the pixel processor and the context memory. Further, the context memory controller may be responsive to a context initialization signal or the like provided by the pixel processor to initialize the content of the context memory to a known state, even before the pixel processor has completed its image processing operations and/or immediately after completion of its image processing operations. In one embodiment, the pixel processor executes a JBIG coding operation on the target pixel.

Abstract: Various implementations are described. Several implementations relate to one or more encoding modes that use depth information to determine a corresponding reference block. According to a general aspect, a portion of a first-view image from a first view in a multiple-view system is encoded. The portion is all or part of the first-view image. It is determined that a portion of a second-view image from a second view in the multiple-view system corresponds to the portion of the first-view image. The determination is based on a second-view depth value providing depth information for the portion of the second-view image. The portion of the second-view image is encoded using information from the encoding of the portion of the first-view image.

Abstract: A method, medium, and apparatus encoding and/or decoding an image according to human psycho-visual characteristics. According to a method, medium, and apparatus, error values corresponding to a range in which error values can be recognized because of the human psycho-visual characteristic are selectively encoded.

Abstract: A method and apparatus for encoding/decoding an image, wherein the method includes selecting a predetermined binarization table from a plurality of binarization tables based on prediction values of a current pixel and binarizing or inversely binarizing residual values by using the selected binarization table.

Abstract: A method for decoding a stream of coded data representative of a sequence of images divided into blocks is described. It comprises the following steps for a current block: reconstructing a residual block of residual data from the decoding of a first part of the coded stream of data relating to the current block, determining a prediction block, and reconstructing the current block by merging the residual block and the prediction block, According to the invention, the decoding method comprises in addition a step of reorganization of residual data in the residual block before the reconstruction of the current block according to the content of the prediction block. The invention also relates to a method for coding.

Abstract: Provided is a method and apparatus for encoding and decoding a multiview image. By predicting a current picture based on at least one of an intra (I) picture of a previous image processing block and an I picture of a current image processing block, which is generated for a different view than a view at which the I picture of the previous image processing block is generated, and encoding the current picture based on the prediction, it is possible to prevent display quality degradation that may occur in images at views other than a base view.

Abstract: A method and apparatus of improving the compression efficiency of a motion vector is provided. The method includes obtaining a motion vector in a base layer frame having a first frame rate from an input frame, obtaining a motion vector in a first enhancement layer frame having a second frame rate from the input frame, the second frame rate being greater than the first frame rate, generating a predicted motion vector by referring to a motion vector for at least one frame among base layer frames present immediately before and after the same temporal position as the first enhancement layer frame if there is no base layer frame at the same temporal position as the first enhancement layer frame, and coding a difference between the motion vector in the first enhancement layer frame and the generated predicted motion vector, and the obtained motion vector in the base layer.

Abstract: In image predictive encoding according to an embodiment, one or more motion information sets are derived from plural pieces of motion information stored in a computer readable storage medium. Each of the one or more information sets includes two pieces of motion information between which any one of constituent elements differ in value. A predicted signal of a target region in a picture is generated by motion compensation, using two pieces of motion information in a motion information set selected from the one or more motion information sets. The two pieces of motion information in the selected motion information set are stored in the computer readable storage medium, and are used for generation of a predicted signal of another region.

Abstract: The present invention relates to an image processing device, an image processing method, and a program that can reduce usage of memory bandwidth when motion compensation operations with fractional precision are performed in inter predictions. A reference image read unit reads predetermined reference pixels from a reference image in an inter prediction so that the number of the predetermined reference pixels corresponding to an outer pixel in a predicted image in the inter prediction is smaller than the number of the predetermined reference pixels corresponding to an inner pixel in the predicted image. Using the read predetermined reference pixels, a 2-tap FIR filter, a 4-tap FIR filter, or a 6-tap FIR filter calculates a pixel having a fractional position in the reference image as a pixel in the predicted image. The present technique can be applied to encoding devices that perform compression encoding by H.264/AVC, for example.

Abstract: An exemplar dictionary is built from example image blocks for determining predictor blocks for encoding and decoding images. The exemplar dictionary comprises a hierarchical organization of example image blocks. The hierarchical organization of image blocks is obtained by clustering a set of example image blocks, for example, based on k-means clustering. Performance of clustering is improved by transforming feature vectors representing the image blocks to fewer dimensions. Principal component analysis is used for determining feature vectors with fewer dimensions. The clustering performed at higher levels of the hierarchy uses fewer dimensions of feature vectors compared to lower levels of hierarchy. Performance of clustering is improved by processing only a sample of the image blocks of a cluster. The clustering performed at higher levels of the hierarchy uses lower sampling rates as compared to lower levels of hierarchy.

Abstract: In one embodiment the present invention includes a digital image processing method for concealing errors. The method includes determining error pixel locations based on motion vectors and determining if the error pixel locations in a current frame are on an edge of an object in the current frame. If an error pixel location is on an edge, then a search of pixel values is performed in the current frame along the edge for a replacement pixel value. If the error pixel location is not on an edge, then a search of pixel values is performed in a region adjacent to the edge for the replacement pixel value.

Abstract: Provided are a lift-based wavelet transform apparatus and method, a scalable video coding apparatus and method using the same, and a scalable video decoding apparatus and method. The lifting-based wavelet transform apparatus includes: a prediction unit which performs bi-directional motion compensation on odd-indexed frames based on even-indexed frames and generates high-frequency frames using differential frames from which most of energy is removed; an update determination unit which, in the even-indexed frame, determines whether to update each target block at which a reference block indicated by a motion vector is placed; and an update unit which updates a target block of the even-indexed frame which is determined to be updated by adding the differential frame to each target sub-block included in the target block and generates low-frequency frames.

Abstract: An encoder, a decoder, an encoding method and a decoding method are provided. The encoder includes a reversible color transform module, a difference pulse code modulation (DPCM) intra prediction module, a quantization module, a reversible frequency transform module and an entropy coding module. The reversible color transform module performs a reversible color transform to output a transformed video signal according to an input video signal. The DPCM intra prediction module performs a DPCM intra prediction to output a least residual according to the transformed video signal. The quantization module performs a quantization operation to output a quantization coefficient according to the least residual. The reversible frequency transform module performs a reversible frequency transform to output a frequency coefficient according to the quantization coefficient. The entropy coding module performs entropy coding to output a compression bit stream according to the frequency coefficient.

Abstract: A data element can be encoded into multiple encoded data elements using an encoding algorithm that includes an encoding function and one or more encoder constant. The encoded data elements can be organized into multiple pillars, each having a respective pillar number. Each of the pillars is sent to a different storage unit of a distributed storage network. To recover the original data element, the encoded data elements are retrieved from storage, and the encoder constant is recovered using multiple encoded data elements. Recovering the encoder constant allows the encoding algorithm originally used to encode the data elements to be determined, and used to recover the original data element. The security of the stored data is enhanced, because an encoded data element from a single pillar is insufficient to identify the encoder constant.

Abstract: A method and apparatus for encoding/decoding an image are provided. The method includes partitioning an image into a plurality of areas, allocating the partitioned plurality of areas to views of multi-view image sequences, and encoding the allocated plurality of areas. By doing so, the method can efficiently encode a large-screen image or a high-pixel image, without using a separate codec.

Abstract: Information that includes first information identifying integer quotients obtained by divisions using prediction residuals or integers not smaller than 0 that increase monotonically with increases in the amplitude of the prediction residuals, as dividends, and a separation parameter decided for a time segment corresponding to the prediction residuals or a mapped integer value of the separation parameter, as a modulus, and second information identifying the remainders obtained when the dividends are divided by the modulus is generated as a code corresponding to the prediction residuals, and each piece of side information that includes the separation parameter is subjected to variable length coding.

Abstract: We present a method for predictive compression of time-consistent 3D mesh sequences supporting and exploiting scalability. The applied method decomposes each frame of a mesh sequence in layers, which provides a time-consistent multi-resolution representation. Following the predictive coding paradigm, local temporal and spatial dependencies between layers and frames are exploited for layer-wise compression. Prediction is performed vertex-wise from coarse to fine layers exploiting the motion of already encoded neighboring vertices for prediction of the current vertex location. Consequently, successive layer-wise decoding allows to reconstruct frames with increasing levels of detail.

Abstract: A method for coding a current block is disclosed. The method comprises: determining a prediction block from the current block, determining a residue block by extracting from the current block the prediction block, and coding the residue block. The prediction block from the current block is determined according to the following steps for: determining an initial prediction block from motion data and at least one reference image previously coded and reconstructed, applying an atomic decomposition method on a vector of data Ycp, comprising the image data of neighbouring blocks of the current block previously coded and reconstructed and the data of the initial prediction block, and extracting from the decomposed vector the data corresponding to the current block, the extracted data forming the prediction block.

Abstract: The present disclosure relates to an image processing apparatus and method, which can improve the coding efficiency while suppressing an increase in the load. Included are: a region setting unit for setting a size in a vertical direction of a partial region to be a process unit upon coding an image as a fixed value and setting a size in a horizontal direction thereof depending on a value of a parameter of the image; a predicted image generation unit for generating a predicted image using the partial region set by the region setting unit as a process unit; and a coding unit for coding the image by use of a predicted image generated by the predicted image generation unit. The present technology can be applied to an image processing apparatus, for example.

Abstract: An image decoding method decodes a coded stream which includes plural processing units and a header of the processing units, and which is generated by coding a moving picture using inter prediction, the processing units including at least one processing unit divided in a hierarchy, the hierarchy including: a highest hierarchical layer in which a coding unit exists as a largest processing unit; and a lower hierarchical layer in which a prediction unit exists. The method comprises: identifying, by parsing hierarchy depth information stored in the header and indicating a hierarchical layer higher than a lowest hierarchical layer in which a smallest prediction unit exits, a hierarchical layer which is indicated by the hierarchy depth information or a hierarchical layer higher than the indicated hierarchical layer, the hierarchical layer having a prediction unit in which a reference index is stored; and decoding the prediction unit, using the reference index.

Abstract: The present invention relates to image encoding and image decoding. A method for encoding images according to the present invention comprises the steps of: acquiring division information from peripheral blocks of an encoding target block with respect to the peripheral blocks; predicting the division of the encoding target block on the basis of the acquired division information; encoding information on the difference between the practical division information of the encoding target information and the predictive division information predicted in the predicting process; and transmitting the encoded information. The present invention can encode/decode the division information of the encoding/decoding target blocks using the information about the peripheral blocks.

Abstract: According to one embodiment, a prediction unit generates a prediction block to be used for prediction of a coding target block, based on at least one reference block adjacent to the coding target block in the image. Each number of pixels in the coding target block and the prediction block is a power of two. A calculation unit calculates a residual block having residual pixel values between the coding target block and the prediction block. A decision unit decides whether to code the residual block, based on pixel values of at least one of the coding target block, the reference block and the prediction block. A coding unit codes the residual block by variable length coding, when the residual block is decided to be coded, and codes a skip flag representing the residual block not being coded when the residual block is not decided to be coded.

Abstract: A method of processing components of an image for coding of an image portion of the image, the image being composed of a first component and a different second component. Samples of the second component are predictable from samples of the first component using a prediction model having a model parameter value. The method comprises: determining a plurality of subsets of samples usable for computing the model parameter value, wherein each subset of samples comprises samples of neighbouring borders of the first component and the corresponding second component of the image portion, according to at least one predetermined sampling pattern and corresponding predetermined shifting offset, selecting, based on predetermined criteria, a subset of samples from among the plurality of subsets of samples; and predicting samples of the image portion using the prediction model and the model parameter value determined from the selected subset of samples.

Abstract: The present invention relates to a method for conducting interlayer texture prediction in encoding or decoding of video signal. The present method constructs a pair of frame macro blocks from vertically-adjacent two field macro blocks of a base layer, selectively applies a de-blocking filter to the constructed pair of frame macro blocks, and uses texture information of the pair of frame macro blocks in interlayer texture prediction of a pair of frame macro blocks of a current layer.

Abstract: Provided is a multilayer picture encoding/decoding apparatus and method for reducing a dynamic range of residual pictures occurring in enhancement layers. The multilayer picture encoding method includes performing format down-conversion on an input picture, and generating a lower layer bitstream by encoding the format down-converted input picture; performing format up-conversion by adaptively or selectively applying a 1-dimensional (1-D) prediction filter to a picture of the lower layer depending on whether a lower layer prediction flag is set or not; and calculating a residual picture between the input picture and the format up-converted picture, and generating an enhancement bitstream by encoding the calculated residual picture.

Abstract: Methods and systems for geometry compression. In an embodiment, the present invention compresses three dimensional geometry by (1) extracting at least one primitive from the three dimensional geometry, where each extracted primitive includes vertices and property indices that associate properties with the vertices; (2) quantizing, for each extracted primitive, the properties to a fixed grid; (3) converting, for each extracted primitive, the properties from a first data type to a second data type; and (4) encoding property indices, where the encoded property indices and quantized and converted properties are transmitted via a communication network in order to display the three dimensional geometry.

Abstract: An apparatus calculates a change predicted value of a value of an interest pixel included in an interest field. The apparatus calculates a change predicted value before correcting the value of the interest pixel based on the interest field and at least one of fields which neighbors the interest field and is stored in the plurality of field memories, respectively calculates interframe difference coefficients based on any of two fields having a field interval of 2 of a plurality of fields stored in the plurality of field memories, and a field which is being input, calculates a correction value of the change predicted value based on the interframe difference coefficients calculated, and corrects the change predicted value before correction calculated by the change predicted value calculator based on the correction value calculated by the correction value calculation unit and output a change predicted value after correction.

Abstract: The image processor 1 includes a frequency transform unit 12, an encoding unit 15, and a memory 4. The encoding unit 15 includes a DC processing unit 31 that generates a direct-current stream, an LP processing unit 32 that generates a low-frequency stream, an HP processing unit 33 that generates an upper high-frequency stream and a lower high-frequency stream, and an output unit 34 having output ports 41 to 44 to output the direct-current stream, the low-frequency stream, the upper high-frequency stream, and the lower high-frequency stream to the memory 4.

Abstract: There is provided an image processing device including a sorting section that sorts pixel values of common pixel positions in adjacent sub-blocks included in a block in an image in a manner that the pixel values included in the block are adjacent to one another after the sorting, and a prediction section generates a predicted pixel value for a pixel of a first pixel position of the sub-block using the pixel values sorted by the sorting section and a reference pixel value in the image corresponding to the first pixel position.

Abstract: Disclosed is an imaging apparatus capable of, when a JPEG compression encoding is performed by dividing an image after an image processing into a plurality of blocks, simply performing the JPEG compression encoding and a combination of images after the encoding without encoding efficiency deterioration or a limitation in an image size of the block. The imaging apparatus includes an image processor for horizontally dividing image data into a plurality of blocks and supplying the blocks to an encoder without passing through a storage unit, the encoder for simultaneously storing an initiation address of a corresponding line to be encoded in a corresponding block and a data length after the corresponding line is encoded in the storage unit, and storing information used for a predictive encoding in the storage unit in every corresponding line to be encoded in the corresponding block.

Abstract: A Method and apparatus for encoding and decoding a multi-view image are provided. The method of encoding a multi-view image includes determining whether each of pictures included in multi-view image sequences is a reference picture referred to by other pictures included in the multi-view image sequences for inter-view prediction, and encoding the pictures using at least one of inter-view prediction and temporal prediction based on the determination result, thereby efficiently encoding and decoding the multi-view image at high speed.

Abstract: A moving picture encoding device for encoding a moving picture constituted of a time sequence of frame pictures by motion compensation, the device including: a reference picture generation section configured to generate a reference picture subjected to predetermined picture processing from a reference frame picture, in accordance with an encoding condition of a predetermined area to be encoded; and a motion compensation section configured to calculate a motion compensation value for the predetermined area to be encoded, by using a generated reference picture subjected to the predetermined picture processing.

Abstract: A compression controller is capable of executing prediction mode selection for selecting any one of forward prediction, backward prediction, or bidirectional prediction as a prediction mode used for encoding based on spatial frequencies of an image to be encoded. The compression controller determines whether or not to execute the prediction mode selection based on image mobility information indicating an amount of motion in the image to be encoded.

Abstract: In an image encoding device, a predicted pixel generator generates a predicted value for pixel data based on at least one of pixels adjacent to a pixel to be compressed. A quantization processor quantizes a difference value between the pixel data and the generated predicted value to a quantized value having a smaller number of bits than that of the pixel data to compress the pixel data to the quantized value. In a quantization width determiner, an edge determiner determines whether or not there are both a flat portion and an edge portion, based on a characteristic of the difference value in the group, and an edge pixel determiner determines whether each of pixels included in the group is a pixel in an edge portion or a pixel in a flat portion, based on the difference value, whereby a quantization width used in the quantization processor is determined.

Abstract: A picture prediction encoding device includes: a region division unit for dividing an input picture into a plurality of blocks; a prediction signal generation unit for generating a prediction signal with respect to a pixel signal that is included in a subject block to be processed among the blocks; a residual signal generation unit for generating a residual signal between the pixel signal of the subject block and the generated prediction signal; a signal encoding unit for generating a compressed signal by encoding the residual signal; and a storage unit for decompressing the compressed signal and storing the decompressed signal as a reproduced pixel signal. The prediction signal generation unit is configured to sub-divide the subject block into a plurality of small regions, at least one of the small regions is non-square, and a length of a first side of the non-square small region is longer than a length of a second side that is different from the first side.

Abstract: An image formed in units of macroblocks of 16×16 pixels attached with a band area having a width of “a” pixels serving as a margin area is extracted as a motion compensation image from a reference frame and is regarded as an input image of a filtering process. “a” is a value that is determined in accordance with the number of taps of an FIR filter. A filtering process is performed using such a motion compensation image as an input image, and a prediction image of 16×16 pixels is output as an output image of the filtering process. The prediction image is added to an output image of an inverse orthogonal transformation circuit in an adder circuit, and an image as a result of the addition is used as a macroblock constituting a decoded frame.

Abstract: An image encoding device includes: a first encoding unit for calculating a generated code amount by encoding image data for each GOP (Group of Picture); a code amount control unit for setting quantization information for realizing a target generated code amount based on the generated code amount; a quantization information distinguishing unit for calculating a DCT (Discrete Cosine Transform) coefficient, and distinguishing quantization information that minimizes the summation for each picture of remainders when performing division of the DCT coefficient, as quantization information used for performing the last encoding; a picture-type setting unit for setting a picture type to the image data for each GOP, and when this set picture type differs from the picture type of the distinguished quantization information, matching the picture types by controlling the settings of the subsequent picture types; and a second encoding unit for encoding the image data based on the set picture type.

Abstract: An image encoding method in which when transmitting or storing an image, a frame of the image is divided into predetermined-sized processing regions, and for each processing region, a pixel value of each pixel is predicted for the encoding.

Abstract: The invention is related to a method for compressing images. The proposed method comprises associating perceptual importance parameters with pixels of the image, applying a transform on the image, partitioning the transformed image into code blocks and encoding coefficient bits of a given code block together from a most significant bit plane towards a least significant bit plane, wherein encoding of at least one coefficient is truncated at a truncation bit plane depending on the perceptual importance parameter associated with the pixel to which said code block coefficient corresponds. Truncating encoding of coefficients in dependency on the perceptual importance of the pixel associated with the coefficient allows for truncating coefficients corresponding to perceptually less important pixels at more significant bit planes. So, the overall perceptual quality of the compressed image is enhanced.

Abstract: An encoding method of screen frame and its application of electronic devices, which rapidly detect motion regions and motionless regions from lossless screen frames captured by software, and then encode the motion regions with lower image quality while encode motionless regions with higher quality to display higher quality images and smooth video at a receiving end in real-time. Furthermore, the above-mentioned encoding method is optimized for lossless screen frames which does not need complicated operations of video encoder of prior art, such as motion estimation, motion compensation, etc., so that the method can be implemented with minor system resources and lower latency delay.

Abstract: Pixels with associated pixel values form a sequence of digitized images that are encoded by predicting pixels of the images and encoding the prediction errors. At least a part of the pixels are encoded by determining trajectories, each running through a pixel to be encoded and through other previously encoded pixels from the image of the pixel being encoded and/or from one or more images that are temporally proximate to that image. For each of the trajectories determined, a valuation parameter is in inverse proportion to the deviations in the uncoded associated pixel values of the other pixels along a trajectory. A predicted pixel value of the pixel to be encoded is determined based on the other pixels of the trajectory with the highest valuation.

Abstract: The present invention combines an inter-prediction method using an AMVP mode and an inter-prediction method using a merge mode so as to use the same candidates. The method for decoding video data proposed by the present invention comprises receiving mode information on an inter-prediction method of a current block, determining, on the basis of the received mode information, whether the inter-prediction method to be applied to the current block is an AMVP mode or a merge mode, and selecting a candidate to derive motion information of the current block.

Abstract: String matching is a ubiquitous problem that arises in a wide range of applications in computer science, e.g., packet routing, intrusion detection, web querying, and genome analysis. Due to its importance, dozens of algorithms and several data structures have been developed over the years. A recent breakthrough in this field is the FM-index, a data structure that synergistically combines the Burrows-Wheeler transform and the suffix array. In software, the FM-index allows searching (exact and approximate) in times comparable to the fastest known indices for large texts (suffix trees and suffix arrays), but has the additional advantage to be much more space-efficient than those indices. This disclosure discusses an FPGA-based hardware implementation of the FM-index for exact and approximate pattern matching.

Abstract: A visual dynamic range (VDR) coding system creates a sequence of VDR prediction images using corresponding standard dynamic range (SDR) images and a prediction function. For each prediction image, an encoder identifies one or more areas within the prediction image suitable for post-prediction filtering. For each identified post-prediction area, a post-prediction filtering mode is selected among one or more post-prediction filtering modes. The selected post-prediction filtering mode is applied to output a filtered prediction image. Information related to the post-prediction filtering areas and the selected corresponding post-prediction filtering modes may be communicated to a receiver (e.g., as metadata) for guided post-prediction filtering. Example post-prediction filtering modes that use low-pass averaging filtering or adaptive linear interpolation are also described.

Abstract: The invention provides a method for performing intra-prediction. A target pixel is selected from a plurality of pixels of a current block. A first intra-prediction mode of a left block and a second intra-prediction mode of an up block are then determined. A first prediction value of the target pixel is calculated according to the first intra-prediction mode. A second prediction value of the target pixel is calculated according to the second intra-prediction mode. The first prediction value and the second prediction value are then weighted-averaged to obtain a weighted-average prediction value as an intra-prediction value of the target pixel.