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 (sl[n,
v]) at time tl. The decoded set (animation frame) of the previous instance
is used as the predicted value (si-l[n, v]). The prediction error el[n,
v], i.e. the difference between the current displacement set and the predicted
one, is computed and quantised (el[n, v]). Finally, the quantised samples
are entropy coded (ci[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 (si
[n, v]).