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The delay time is dependent on the number of image elements included within a block. The video sign is supplied from the delay circuit 2a to a subtractor 2b. Here the distinction between the image signal, and the prediction sign provided via a line 105a branching from an output line 105 foxz168 of a prediction signal generator 5, is produced, and the difference, i.e. the prediction error signal, is then equipped to a quantizer three which functions to limit the number of attainable ranges.
Means for compressive coding of knowledge, stated info containing at least info representing mentioned optimum prediction function and information representing a prediction error delivered out of mentioned predictive coding means when said optimum prediction function is used. The code compressor 7 has a data rate matching function which permits compressed info to be output at a continuing knowledge fee, and it includes a prediction error sign encoder 7-1 connected between line 103a and a multiplexor 7-3, and a motion vector encoder 7-2 connected between line 108b and multiplexor 7-3 as proven in FIG. An adaptive coding system in accordance with declare 4 whereby said code length of stated variable word length code is minimum for stated inter-frame prediction and will increase as the norm of said prediction perform increases. An adaptive coding system according to declare 2 whereby mentioned first analysis means evaluates stated prediction perform by encoding it right into a variable word size code which has the minimal code length for the inter-frame prediction.
Generally speaking, a perform that makes smallest the prediction error is outlined because the foxz168 optimum operate. Consequently, the movement compensation inter-frame prediction system may be thought-about as an adaptive prediction coding system which adaptably determines a most adaptive prediction function among many prediction features.
9 is a block diagram exhibiting intimately the prediction signal generator 5 in FIG. 4A. In the determine, a two-dimensional memory 5-1 has considerably the same structure as that of the two-dimensional reminiscence 8-11 included in the arithmetic unit 8-1.
This worth was obtained when the sampling frequency was 8 MHz, so that data of about zero.8M bits/sec. Was dedicated to the motion vector information alone. Accordingly, where a television sign is transmitted at a transmission velocity of 1.5M bits/sec., the motion vector information would occupy somewhat greater than 50% of everything of data transmitted. A predictive coding methods operates based on a precept that a distinction between a sign to be transmitted and a prediction signal is transmitted in order to lower the amount of transmission information. This invention contemplates an adaptive predictive coding system whereby a plurality of prediction capabilities that give the prediction alerts are used and an optimum one of many prediction functions is used for performing a prediction coding operation. Thus, the controller 301 receives a signal representative of the occupancy of the buffer memory 300 via a line one hundred ten, and designates the quantizer 3, optimum prediction detector 8 and code compressor 7 via line 111, and designates the quantizer 3, the optimum prediction detector eight, the code compressor 7 and the interpolator 302 by way of line 112.
Preferably, the motion vector information is coded into a variable word size code which has the minimum code length for the inter-frame prediction. Specifically, the code length of the variable word length code is minimal for the inter-frame prediction and will increase as the norm of the motion vector increases. In the past, a comparatively excessive transmission pace was assumed so that it has been thought-about that the percentage of the motion vector info is negligibly small. Consequently, it has been thought of that an optimum prediction which minimizes the amount of everything of data transmitted may be realized by detecting a movement vector which minimizes the amount of information representing a prediction error.
For the predictive coding system using motion compensation, the range of correction, i.e., the variety of vectors N, should preferably be as massive as possible and the variety of image components in a block be as small as possible. From this viewpoint, the tactic of during which needed hardware is set by the value of N and a wide variety of movement compensation disadvantageously needs an elevated hardware. In distinction, the tactic of primarily makes use of M arithmetic units repeatedly for N instances, and the hardware requirement is virtually determined by the value of M. Thus, it can be seen that the method of is extra advantageous. The address of the prediction sign generator memory 8-11a for writing the above-mentioned supplementary picture parts is ideally next to the addresses for storing picture parts that are necessary for determining the optimum prediction perform for the current block, for facilitating read/write management. For this purpose, A1 by way of A8 are written following the addresses for storing x1 through x16 as shown in FIG. The necessary storage capacity of the prediction signal generator memory 8-11a is expressed, utilizing symbols k, L, m and n, as (2m+k)×(2n+L) for figuring out the optimum prediction function of the current block, k×(2n+L) for supplementary picture components for determining the optimum prediction perform of the subsequent block, amounting to 2(m+k)×(2n+L) in whole.