Progressive image transmission based on image projections

We present a progressive image transmission coder, where geometrical vector quantization is applied to overlapped image projections. Progressive image transmission is widely used in many applications, because it offers successive improved reconstructions of an image. It is possible to have a rough version of information available in a very short time and, then, the viewer can decide whether further transmission is necessary or not. In the proposed coding scheme the still image is subdivided into circular partially overlapped regions and, then, some projections along predefined directions are determined and vector quantized by using geometrical VQ. The utilization of overlapped circular regions exploits the spatial redundancy present on the image, as the block subdivision does, and at the same time, it avoids the problem of blocking artifacts. The projection technique allows the detection of the most important information locally present on the image