Abstract: A method and system for contour-based motion estimation for use with video images. The invention establishes corresponding contours (404, 414) in two images (402, 412) in a sequence of images, determines a motion vector which includes how the first contour (404) moved to become the second contour (414), and transmits the motion vector of the contour (414) in order to permit accurate display of the second video image (412). Preferably, boundary lines are removed from the contours before a comparison is made. The invention is computationally efficient and economical from a data transmission point of view, while enabling the production of accurate image.

Abstract: A method for coding a digital moving video including gray scale shape information. Picture-unit overhead information is first transmitted and it is then determined whether a video packet to be coded is a first packet of a given picture. A video packet header including overhead information for the decoding of the gray scale shape information is transmitted if the video packet is not the first packet of the given picture. Then, it is determined whether the given picture is an intra picture. If the given picture is the intra picture, the video packet is coded and transmitted in an intra picture mode. If the given picture is not the intra picture, the video packet is coded and transmitted in an inter picture mode. If the video packet is not a last packet of the given picture, a digital moving video coding operation is performed repeatedly. The digital moving video coding operation is ended if the video packet is the last packet of the given picture.

Abstract: A plurality of layers having other resolution are coded in order to encode scalably shape information. A base layer having the lower resolution is coded and transmitted to a decoder, and an enhancement layer is coded by employing a scan interleaving method from the base layer. A scan order of vertical and horizontal scannings is decided according to a generation frequency of TSD (transitional sample data) and ESD (exceptional sample data) and the number of coding bits on the base layer, or a type of boundary lines on images. When the scan order is decided, additional information indicating the scan order is transmitted to the decoder. The base layer is also coded and transmitted to the decoder. In case that the scan order is decided according to the horizontal and vertical of the boundary lines on an image of the base layer, it is no need to transmit the additional information indicating the scan order on the received base layer and execute the decoding in the same order as the coded scan order.

Abstract: A rate control apparatus for real-time video communication includes: an initialization unit for setting an initial value required for rate control according to a transmission speed and the number of input frames; a target bit calculation unit for obtaining the target number of encoding bits, maximum allowable number of bits, and minimum allowable number of bits in consideration of a buffer state and a transmission speed; a rate control and encoder unit for executing rate control and encoding using the maximum allowable number of bits and the minimum allowable number of bits; a stuffing control unit for comparing the size of a bit stream from the rate control and encoding unit with the target number of encoding bits from the target bit calculation unit for thereby outputting stuffing bits; a buffering unit for storing a combination of the bit stream from the rate control encoding unit and the stuffing bits from the stuffing control unit for thereby outputting them to the target bit calculation unit; a frame sk

Abstract: A method and apparatus for updating motion vector memories used for prediction of motion vectors in a video compression coding/decoding method and system. For a frame composed of N macroblocks in the horizontal direction, only (2N+1) motion vector memories are used to store all motion vectors necessary to motion Prediction, and only three memories per macroblock are used to update motion vectors, thereby reducing the size of a circuitry, the amount of computation and the amount of power consumed.

Abstract: A method and an apparatus for predictively coding shape information of a video signal. An error between the current shape information and the previous shape information is obtained through the comparison therebetween. If the obtained error is greater than or equal to a predetermined reference value, the current shape information is coded. However, in the case where the obtained error is smaller than the predetermined reference value, the current shape information is reconstructed using the previous shape information. Therefore, a time-axis redundancy of the shape information is removed to prevent the transmission of unnecessary information, resulting in an increase in compression coding efficiency.

Abstract: A motion vector estimation apparatus in a digital video coding system and a method thereof. More particularly, the present invention relates to a motion estimation method and apparatus for, prior to a motion vector estimation operation, determining whether to perform it and selectively performing the motion vector estimation operation in accordance with the determined result, thereby reducing the coding time period and the amount of power consumed.

Abstract: A method and apparatus for compression transformation and inverse transformation of a digital image wherein, for the transformation and inverse transformation, a determination is made as to whether all input data values are 0, and an unnecessary transform process is skipped if all the input data values are determined to be 0, thereby reducing power consumption resulting from the unnecessary transform process. The present method and apparatus can very simply be implemented and minimize power consumption. Therefore, the present invention is significantly effective in implementing a low-power video codec essential to mobile communication terminals.

Abstract: A motion estimation method and device for selecting a final motion vector to be coded, in consideration of a zero vector and a predicted motion vector as well as a motion vector having a minimum error, thereby increasing a video coding efficiency.

Abstract: A method and an apparatus for predictively coding a contour of a video signal. An error between the current contour and the previous contour is obtained through the comparison therebetween. If the obtained error is greater than or equal to a predetermined reference value, the current contour is coded. However, in the case where the obtained error is smaller than the predetermined reference value, only a signal indicative of the reconstruction of the current contour using the previous contour is transmitted to a decoder. Therefore, the transmission of unnecessary information is prevented to enhance the compression coding efficiency.

Abstract: A sequential polygon approximation apparatus for a contour and a method thereof which are capable of sequentially extracting a vertex in the order of a contour pixel when performing a polygon approximation so as to code a shape information, which includes an error computation unit for obtaining a contour pixel between two contour pixels of the vertex extraction unit from the contour pixel memory and computing an error which is a distance between a straight line between two contour pixels and a pixel from the contour pixel memory, a comparison unit for comparing an error obtained by the error computation unit with a threshold value, and a controller for controlling the vertex extraction unit and the error computation unit in accordance with the comparison result of the comparison unit, setting the pixel just before the final pixel of a first region as a first vertex when the error obtained in the first region which is the region of the contour pixel sequentially determined for the vertex extraction from a fixe

Abstract: A method for determining a coding type and a coding mode for object shape coding is disclosed. A coding mode is determined according to the characteristic of an object and shape, and the shape is coded by varying a coding method according to the determined coding mode.

Abstract: An object-by shape information compression apparatus and a method thereof, which includes a motion compensation prediction circuit provided for motion-compensation-predicting a shape information of a current fame using a shape information of a previous frame and a motion information of a current frame; a subtraction circuit provided for computing a prediction error region by subtracting a shape information predicted by the motion compensation prediction circuit and a current motion region; a threshold operation circuit provided for determining a transfer and disconnection of an information in accordance with time by threshold-operating an isolated prediction error region obtained by the subtraction circuit; a contour prediction circuit provided for compression-coding a shape information by predicting a contour in a prediction error region obtained by the threshold operation circuit; a contour reconstruction circuit provided for reconstructing an isolated prediction error region from a contour coded by the con