Previous vertices on a previous contour are mapped onto a current contour in this method to form a predicted vertex on the current contour corresponding to each of the previous vertices and vertex displacements between the previous vertices and their corresponding predicted vertices are calculated. After current vertices on the current contour being determined, the current contour is coded based on either the current vertices to thereby provide intra-coded data or the previous contour to provide inter-coded data; and either the intra-coded data or the inter-coded data is selected based on the vertex displacements as encoded data for the current contour.

Method and apparatus for encoding a video signal of a contour of an object

A method for encoding a contour of an object predicts a current contour by using a current and a reconstructed previous contours and generates the motion vector representing a displacement between the reconstructed previous and the predicted current contours. A matched contour between the predicted current and the current contours is subtracted from the current contour to provide a differential contour. Thereafter, vertex points is determined based on a polygonal approximation for the differential contour. A set of approximation errors calculated at a predetermined number of sample points on each line segment between two vertex points is transformed and quantized to obtain a set of quantized discrete sine transform coefficients. The quantized discrete sine transform coefficients are encoded together with the motion vector, and the vertex points are encoded based on the predicted current contour for transmission thereof. And, the coded vertex information is decoded based on the predicted current contour, and the quantized discrete sine transform coefficients are converted into the reconstructed errors to reconstruct the differential contour. The reconstructed differential contour is added to the matched contour to provide the reconstructed previous contour.

Method for encoding a contour of an object in a video signal by using a contour motion estimation technique

A method of vertex-based hierarchical shape representation and coding includes selecting an image of interest, defining a boundary about an object of interest within the image of interest, wherein the boundary is defined by a set of contour points, selecting a number of layers, each layer having a predefined saliency parameter associated therewith, wherein the saliency parameter defines a range of layers from a most salient layer to a least salient layer, identifying the most salient contour points in the boundary and placing the most salient contour points in the most salient layer, identifying the next most salient contour points in the boundary and placing the next most salient contour points in the next most salient layer until all of the selected layers have contour points placed therein, and hierarchically storing the layers in a database. A vertex-based hierarchical shape representation and coding system includes an image input which contains and image of interest, an analyzer to select an object of interest within the image, a manipulation mechanism to define a boundary about the object of interest and define a set of contour points on that boundary, and a selections mechanism to place selected contour points into hierarchical layers of like salient contour points.

Vertex-based hierarchical shape representation and coding method and apparatus

A method for coding multiple layer, vertex-based shape representation and bit stream scaleable shape includes selecting vertices in a hierarchical scheme; defining multiple layers of vertices; arranging M layers of vertices in order, from the most salient layer to the least salient layer; placing vertices in their natural order along their image contour within each layer; storing vertices from each layer separately; and recording vertex order information for each vertex in each layer of vertices. Four variations of the method for multiple layer vertex representation and coding are disclosed where the correct order information is coded for correct reconstruction of the shape information.

Methods of coding the order information for multiple-layer vertices

A contour image coding method divides a video frame into a multiplicity of blocks and detects contour blocks and determines a plurality of vertices on each contour segment included in each contour block and codes the contour image based on the vertices on each contour segment for each contour block.

Method and apparatus for encoding a contour image in a video signal

A contour approximation apparatus for representing a contour image of an object comprises a polygonal approximation section for determining a number of vertices on the contour image and fitting the contour image with a plurality of line segments to provide a polygonal approximation of the contour image, a sampling circuit for providing N sample points for each of the line segments, an error detector for calculating an error for each of the N sample points on each of the line segments to produce a set of errors for each of the line segments, a discrete sine transform and quantization block for transforming each set of errors into a set of discrete sine transform coefficients, and for converting the set of discrete sine transform coefficients into a set of quantized transform coefficients.

Jong-Lak Kim

Papers

A contour approximation apparatus for representing a contour of an object