Image signal decoding apparatus

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG.
1 is a block diagram showing the structure of a decoding apparatus embodying the present invention in an image data transmission system using a DC separation vector quantization method.
Reference numeral 10 designates an input terminal for receiving transmission data supplied from a transmission line.
Transmission data compressed by the DC separation vector quantization are inputted to the input terminal 10.
A data deficiency decision circuit 12 decides presence/absence of data deficiency in each data block of the transmission data.
A data separation circuit 14 separates each data block of the transmission data into a mean value data m (block characteristic information) of image data and a vector quantized data i (image information in data block) obtained by quantizing the data obtained by subtracting the image data mean value m from the image data in a data block.
An inverse vector quantization circuit 16 inversely quantizes the vector quantized data i.
An addition circuit 17 adds together the data outputted from the inverse quantization circuit 16 and the image data mean value m of the data block outputted from the data separation circuit 14.
A mean value data memory 18 stores therein mean value data of one frame blocks.
A motion decision circuit 20 decides a presence/absence of an image motion of each block by comparing the presently supplied mean value data with the mean value data already stored in the mean value data memory 18.
A motion information memory 22 stores therein a decision result obtained by the motion decision circuit 20.
An interpolation decision circuit 24 decides an interpolation method by estimating an presence/absence of an image motion in a deficient block in accordance with image motion information on a nearby data block.
An adaptive interpolation circuit 26 carries out an inter-frame interpolation for a block belonging to a still image area, and an intra-frame interpolation for a block belonging to a moving image area, respectively in accordance with a decision given by the interpolation decision circuit 24