Abstract: An image encoding method and apparatus, and an image decoding method and apparatus respectively corresponding to the image encoding method and apparatus are provided. The image encoding method includes: if a current block is an initial block of a current slice, determining whether a virtual block in which pixel values are equal to a predetermined value is identical to the current block; and encoding the current block in a first mode based on the determining, wherein the first mode is a mode for encoding information representing that the current block is encoded in the first mode, instead of encoding pixel values of the current block, when the current block is identical to the virtual block.

Abstract: Provided are an image processing method and image processing apparatus using least significant bits (LSBs). The image processing method includes generating first binary codes by converting pixel values of an input image into a binary code format; converting the first binary codes into gray codes and determining a predetermined number of sequential LSBs from among the gray codes; and generating second binary codes by converting the determined LSBs of the gray codes into the binary code format.

Abstract: Methods and apparatuses for generating video packets are provided. A method of generating a video packet includes generating at least one pixel block including at least one reference pixel and at least one neighboring pixel adjacent to the at least one reference pixel from pixels of a video frame; replacing a pixel value of the at least one neighboring pixel in the at least one pixel block with a pixel difference value, which is a difference value between a pixel value of a pixel adjacent to the at least one neighboring pixel and the pixel value of the at least one neighboring pixel; and generating packets so that a pixel value of the at least one reference pixel and the pixel difference value of the at least one neighboring pixel are allocated to different packets according to positions of the pixels.

Abstract: An encoding method includes selecting a run detection method in accordance with characteristics of image data, generating a run value by detecting a run that is repeated in the image data in accordance with the selected run detection method, generating run count bits by counting the number of repetitions of the detected run, and performing a run-length encoding using the detected run values and the run count bits. The run detection method includes a coefficient run detection method that detects a run based on pixel values, a pattern run detection method that detects the run based on whether the pixel blocks have a specified pattern, a difference run detection method that detects the run based on a difference value between two successive pixel values, and a residual run detection method that detects the run based on an error value that is a difference value between an actual pixel value and a predicted value.

Abstract: A method and apparatus for implementing cloud computing by efficiently encoding a display screen between a cloud server and a client terminal. The method for encoding a cloud display screen in the cloud server, includes: acquiring region information of currently generated windows based on an application programming interface (API) function information of an Operating System (OS); extracting relative depth information between each of the currently generated windows from the OS; generating an encoding mode map in which an entire screen is divided into a plurality of blocks, based on the acquired region information and the extracted relative depth information; and encoding each of the plurality of blocks based on the generated encoding mode map.

Abstract: Provided are methods and apparatuses for encoding data. One method of encoding data includes generating second data by altering locations of bits within first data to be encoded next based on values of bits within at least one piece of previously encoded data; and entropy-encoding the second data. Also provided are methods and apparatuses for decoding data.

Abstract: A method and apparatus for encoding and decoding an image. The encoding method includes: deciding whether pixel values of a first block of an image are identical to pixel values of a second block of the image that is encoded prior to the first block in a current slice of the image, and determining whether to encode the first block in a first mode according to the deciding; and selectively encoding the first block in the first mode based on the determining, wherein the first mode is a mode for encoding information representing that the first block is encoded in the first mode, instead of encoding the pixel values of the first block, when the first block is identical or similar to the second block.

Abstract: A method and apparatus for decoding hierarchical mode information including mode information indicating whether a current block is encoded in an encoding mode identical to an encoding mode of a plurality of consecutive previous blocks.

Abstract: A method and apparatus are provided for encoding and decoding an image which entropy encode and decode a residual value of a current pixel in consideration of a context model determined with reference to at least one pixel value that is encoded and decoded before the current pixel and distribution of the residual values encoded and decoded according to the determined context model.

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: Provided are method and apparatus for encoding and decoding an image by using a bit plane-based image encoding method and a block-based image encoding method respectively on bit planes based on the n-m most significant bits of an input image including n-bit pixel values and an image based on the m least significant bits of the input image.

Abstract: A method to encode and decode a halftone image such that the halftone image is efficiently compressed and decoded by using pattern characteristics of the halftone image includes determining different template shapes according to characteristics of the halftone image, compressing the halftone image based on determined template shape information, compressing the template shape information, and generating the compressed halftone image and the compressed template shape information as a bitstream.

Abstract: Provided are methods and apparatuses for converting a lower bit-plane image, and methods and apparatuses for inverse-converting the lower bit-plane image, which increase the correlation of the lower bit-plane image. According to the method of converting a lower bit-plane image, pixels of the lower bit-plane image are sequentially added or subtracted so as to generate a converted lower bit-plane image. Accordingly, the lower bit-plane image has higher regularity, and thus the efficiency of image processing using the lower bit-plane image is improved.

Abstract: A method and apparatus for processing a video frame is provided. The method includes dividing the video frame into pixel blocks each including a reference pixel; calculating difference values between the reference pixel and pixels neighboring the reference pixel; converting the calculated difference values into values that belong to a bit depth range; and performing entropy coding by using the converted difference values as symbols.

Abstract: A method and apparatus for generating video packets and a method and apparatus for restoring video are provided. The method of generating video packets includes: generating at least one pixel block consisting of at least one reference pixel and a plurality of neighboring pixels adjacent to the at least one reference pixel from pixels of a video frame; replacing pixel values of the neighboring pixels in the at least one pixel block with pixel difference values, which are difference values between a pixel value of one of pixels adjacent to the neighboring pixels and the pixel values of the neighboring pixels; generating packets so that a pixel value of the at least one reference pixel and the pixel difference values of the neighboring pixels are allocated to different packets according to positions of the pixels; and performing entropy coding of some of the packets including the pixel difference values of the neighboring pixels.

Abstract: Methods and apparatuses for generating video packets are provided. A method of generating a video packet includes generating at least one pixel block including at least one reference pixel and at least one neighboring pixel adjacent to the at least one reference pixel from pixels of a video frame; replacing a pixel value of the at least one neighboring pixel in the at least one pixel block with a pixel difference value, which is a difference value between a pixel value of a pixel adjacent to the at least one neighboring pixel and the pixel value of the at least one neighboring pixel; and generating packets so that a pixel value of the at least one reference pixel and the pixel difference value of the at least one neighboring pixel are allocated to different packets according to positions of the pixels.

Abstract: An encoding method includes selecting a run detection method in accordance with characteristics of image data, generating a run value by detecting a run that is repeated in the image data in accordance with the selected run detection method, generating run count bits by counting the number of repetitions of the detected run, and performing a run-length encoding using the detected run values and the run count bits. The run detection method includes a coefficient run detection method that detects a run based on pixel values, a pattern run detection method that detects the run based on whether the pixel blocks have a specified pattern, a difference run detection method that detects the run based on a difference value between two successive pixel values, and a residual run detection method that detects the run based on an error value that is a difference value between an actual pixel value and a predicted value.

Abstract: A method and apparatus for encoding and decoding an image. The encoding method includes: deciding whether pixel values of a first block of an image are identical to pixel values of a second block of the image that is encoded prior to the first block in a current slice of the image, and determining whether to encode the first block in a first mode according to the deciding; and selectively encoding the first block in the first mode based on the determining, wherein the first mode is a mode for encoding information representing that the first block is encoded in the first mode, instead of encoding the pixel values of the first block, when the first block is identical or similar to the second block.

Abstract: Methods and apparatuses for encoding and decoding mode information of a block of an image. The method of decoding the mode information includes decoding information representing whether a current block is encoded in a first mode, and hierarchically decoding information representing an encoding mode of the current block from among a second mode and a third mode.

Abstract: A method and apparatus for decoding an image are provided. The method includes: decoding information representing that a first block of the image has been encoded in a first mode; and reconstructing the first block by setting pixel values of the first block to be identical with pixel values of a second block of the image that is adjacent to the first block and has been decoded prior to the first block, wherein the first mode is a mode for encoding information representing that the first block is identical or similar to the second block and has been encoded in the first mode, instead of encoding the pixel values of the first block.