Kokusai Denshin Denwa Kabushiki Kaisha

Hitomi Murakami

Shuichi Matsumoto

Yoshinori Hatori

Hideo Yamamoto

A noise-shaping predictive coding system is disclosed, in which the deviation (i.e. correlation) of quantization representative values, which occurs when the coding noise resulting from predictive coding is frequency-shaped by a noise shaping filter, is used to perform an coding operation, so that the quantization entropy can be reduced simultaneously. According to another aspect of the present invention, the human visual characteristic may be combined with the deivation of quantization representative values.

Noise-shaping predictive coding system

A predictive TV signal coding system is disclosed, in which a predictive value of a picture element to be coded is obtained from information of an already coded picture element, a representative quantization value of the picture element to be coded is determined in accordance with the magnitude of the predictive value, and a difference value between the representative quantization value and the predictive value is coded for transmission without quantization.

Predictive coding system for TV signals

A TV signal median prediction coding system in which a prediction value of a picture element to be coded is obtained from information of an already coded picture element and a difference between the prediction value and the value of the picture element to be coded is coded. In accordance with the present invention there is provided a storage section having a capacity large enough to store input TV signals of at least one frame at all times; an intrafield prediction section which, when supplied with a value X.sub.1 of the latest input picture element of the TV signal, produces a prediction value X.sub.1N of the latest input picture element using a value of a picture element of the same field as the latest input picture element, read out from the storage section; an interfield prediction section which, when supplied with the value X.sub.1 of the latest input picture element, produces a prediction value X.sub.1K of the latest input picture element using picture elements of the same field as the latest input picture element and the immediately preceding field, read out from the storage section; an interframe prediction section which, when supplied with the value X.sub.1 of the latest input picture element, produces a prediction value X.sub.1F of the latest input picture element using picture elements of the same field as the latest input picture element, the immediately preceding frame; and an adaptive control section which compares the intrafield prediction value X.sub.1N, the interfield prediction value X.sub.1K and the interframe prediction value X.sub.1F in magnitude and selects a median of them as the latest input picture element value X.sub.1.

TV Signal median prediction coding system

An adaptive predictive coding system for television signals, in which noting the movement of a picture, adopts the inter-frame prediction value in a case of the picture being decided to be a still picture and, in other cases, compares the inter-frame, into-field and intra-field prediction values with each other in terms of magnitude taking into account the quantity of movement of the picture and adopts the prediction value which would not make the coding efficiency the worst, spo that a stable and high coding efficiency can be achieved.

Adaptive predictive coding system for television signals

An inter-frame adaptive prediction system for television signals is disclosed in which a prediction value P.sub.1 for a picture element 1 in the current field is newly produced, through using prediction values P.sub.OPT and P.sub.MED obtained by the following two procedures. In a first procedure, the intra-field prediction (a prediction value X.sub.N), the inter-field prediction (a prediction value X.sub.K) and the inter-frame prediction (a prediction value X.sub.F) are performed for a picture element temporally ahead of the picture element in the current field F.sub.0, for instance, the picture element 2, and a prediction circuit which yields a prediction value closer to the picture element value X.sub.2 of the picture element 2 than the prediction values of any other prediction parts is selected, and a prediction value X.sub.1S for the picture element 1 obtainable from the selected prediction circuit is obtained and is used as the prediction value P.sub.OPT. In a second procedure, the intra-field prediction, the inter-field prediction and the inter-frame prediction are carried out for the picture element 1, and prediction values obtained from the three prediction circuits are compared in magnitude with one another to obtain a prediction value corresponding to a median, which value is used as the prediction value P.sub.MED. Therefore, for a picture signal such that the moving and stationary parts are clearly distinguished in the picture, P.sub.OPT obtained by the procedure 1 provides a prediction value close to the true value. On the other hand, for a picture signal such that the moving and stationary parts are not clearly distinguished in the picture, a weighed mean value of the predicted values P.sub.OPT and P.sub.MED is employed.

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Yokohama, Japan

Hitomi Murakami