Coding of animated 3-D wireframe models for internet streaming applications: methods, systems and program products

摘要

A 3-D wireframe model expressed in terms of nodes and vertices receives a 3-D video or like signal representative of a scene expressed in terms of a reference model, I frames and P frames. A DPCM coder takes advantage of the temporal correlation of the displacement of each vertex along every axis in the 3-D space. The 3-D signal is a set of non-zero displacements of all vertices and all nodes (s_l[n, v]) at time t_l. The decoded set (animation frame) of the previous instance is used as the predicted value (s_i-l[n, v]). The prediction error e_l[n, v], i.e. the difference between the current displacement set and the predicted one, is computed and quantised (e_l[n, v]). Finally, the quantised samples are entropy coded (c_i[n, v]) using an adaptive arithmetic coding algorithm to handle the unknown data statistics. The predictive scheme described above prevents quantization error accumulation. A DPCM decoder first decodes arithmetically the received samples (‘e’ [n, v]) and computers the decoded samples (s_i′ [n, v]).