Efficient coding/decoding apparatuses for processing digital image signal

An efficient coding apparatus for use in a coding processing utilizing correlation between frames or fields of an image signal, comprising:

• means for obtaining a signal component including a negative error signal provided by substracting a reproduced image signal obtained by coding/decoding from an original image signal which has not undergone interframe/interfield coding processing, and
• means for adding the signal component including the negative error signal to input image signals of other frames or fields;
• and further comprising:
• means for detecting the degree of matching every block or pixel of an image between frames or fields where interframe or interfield processing is carried out, and
• quantization means such that when the degree of matching is high, the quantization means is operative to allow a quantization step to be coarse, while when the degree of matching is low, the quantization means is operative to allow the quantization step to be fine.

An efficient coding apparatus for use in a coding processing utilizing correlation between frames or fields of an image signal, comprising:

• means for obtaining a signal component including a negative error signal provided by substracting a reproduced image signal obtained by coding/decoding from an original image signal which has not undergone interframe/interfield coding processing, and
• means for adding the signal component including the negative error signal to input image signals of other frames or fields;
• and further comprising:
• means for detecting the degree of matching every block or pixel of an image between frames or field where interframe or interfield processing is carried out,
• means for controlling a quantization step, and
• adding means such that when the quantization step is caused to be coarse, the adding means is operative to increase the rate of a signal component including a negative error signal to input image signals of other frames or fields, while when the quantization step is caused to be fine, the adding means is operative to decrease the rate of a signal component including a negative error signal to add it to those input image signals.

An efficient decoding apparatus comprising means for adding reproduced image signals of other frames of fields to a current or present reproduced image signal in decoding coded data of an image in which error signals of other frames or fields are included;

• wherein said apparatus further comprises
• decoding means for decoding said coded data of said image to a reproduced image signal, said decoding means comprising a buffer, a variable length decoder, an inverse quantizer and an inverse orthogonal transformer,
• a frame memory for storing a reproduced image output which is generated by adding an output of said inverse orthogonal transformer with a motion compensated signal,
• means for detecting the degree of matching every block or pixel of a reproduced image between frames or fields where interframe or interfield processing is carried out, and
• said means for adding being such that when the degree of the matching is high, the means for adding is operative to increase the rate of reproduced image signals of other frames to add them to a current or present reproduced image signal, while when the degree of the matching is low, the means for adding is operative to increase the rate of a current reproduced image signal to add it to reproduced image signals of other frames or fields.