5 is a block diagram exhibiting intimately the scan converter 1 of FIG. 4A. In this embodiment, 2×2 two-dimensional blocks every consisting of two image elements in the horizontal path and two traces in the vertical direction, as proven in FIG. One block consists of four picture elements, e.g. a11, a12, a21 and a22, enclosed by damaged line. In a general television system, the display is scanned from left to proper in the order of, for instance, a11, a12 , a13 and a14, and components a21, a22, a23 and a24 are included on the succeeding scanning line.
In this case, picture elements in a two-dimensional block across a quantity of scanning lines are rearranged, and film parts in each block are reworked in order that image components in a single block continue to these in the subsequent block and all picture components in a two-dimensional block are aligned serially. Accordingly, presence of scanning traces need not be of concern when carrying out prediction coding for picture parts in a two-dimensional block, and a two-dimensional block could be treated identically to a one-dimensional block produced from M picture parts on a single scanning line. As may be seen from the above, when scan conversion is carried out in advance, predictive coding by use sa168vip of two-dimensional blocks can be no extra than predictive coding by use of one-dimensional blocks. According to the current invention, the above process is achieved for dedication of the optimum predictive function by repetitive use of M arithmetic models for N instances, thus, hardware may be made small when the number of picture parts M included in a block is small. Moreover, the prediction error energy for a block for every perform can be obtained by single computation, permitting the choice of an prediction operate to be in contrast next while finishing up the computation. It implies that all of N-times computations usually are not at all times needed for determining the optimum prediction perform.
An adaptive coding system according to declare 2 wherein said prediction function for willpower of the analysis by said second analysis means is managed in accordance with buffer memory occupancy of the system. 11B reveals one example wherein a differential vector signal produces twenty-five vectors on the x-y coordinates, by which digits in circles present the magnitudes, that's, absolutely the values of the vectors. 11A, the pattern of the the size of variable word length code illustrated in reference to the primary quadrant is applied to the remaining quadrants but not depicted for simplicity of illustration. The above patterning of the length of variable word size code is grounded on the next. 4A, parts as designated by 2b, 3, 4, 5 and 6 constitute a typical predictive coder which can schematically be illustrated as shown in FIG. 4B. The provision of the quantizer as proven at dotted line just isn't important.
An example of the tactic of detecting the quantity of displacement, that is, a way of determining an optimum prediction function is disclosed in U.S. No. four,307,420 entitled "Motion-compensated interframe coding system", issued Dec. 22, 1981. According to this patent, prediction errors relating to various prediction features similar to vectors indicative of various movements are compared with one another in block items and a vector comparable to a prediction perform that offers the minimum prediction error is deemed as a motion vector representative of an optimum prediction operate. With regard to the impact of movement compensation, it is acknowledged that by making use of the movement correction for a transferring image, the quantity of knowledge could be decreased to about one-half of the inter-frame coding system, thus attaining considerable compression of information. An assumption is made right here that the picture components included in a block are disposed in a two-dimensional 2-by-2 array as illustrated in FIG.
11A. Further, when the quantizing attribute of the prediction error signal is made tough, image quality degradation inherent to the inter-frame coding referred to as "dirty window" occurs in which quantized noise stands nonetheless on the image in order that as if an image were viewed through a unclean window. On the opposite hand, in the movement compensation inter-frame coding, there arises a brand new downside of degraded image high quality during which the dirty window is seen transferring. The new downside of degrading the picture quality is remarkable at a standstill portion of the television picture image especially when the signal to noise ratio (S/N) of the enter television sign is low. The purpose of prevalence of the degradation of the image high quality in the motion compensation inter-frame coding is as follows. Thus, as described above, within the movement compensation inter-frame coding, the predictive coding operation is effected by using a sign of the preceding body having the highest diploma of similarity to be a sign within the blocks within the current body as a prediction signal. sa168vip ทดลองเล่น However, when the input television sign accommodates noise, even on the standstill portion, the diploma of similarity to a shift vector exhibiting that the blocks are standstill just isn't all the time the utmost with the result that the standstill portion might inadvertently be judged as a transferring portion. Consequently, a grimy window which is standstill within the inter-frame coding is seen transferring within the movement compensation inter-frame coding, thus significantly degrading the image high quality.
4A is a block diagram showing an instance of a predictive coding system, which is situated on the aspect of a transmitter and operates to transmit a signal to a predictive decoding system on the side of a receiver. An input video signal is supplied through line a hundred to a scan converter 1, in which a plurality of blocks, each consisting of numerous image components, are shaped. The block-formation video signal is then provided to a delay circuit 2a and an optimum prediction detector 8 through lines 101a and 101b, respectively, branched from line 101. The delay circuit 2a delays the propagation of the block-formation video sign for a size of time required for figuring out the optimum prediction operate.
One of four parallel image factor outputs is equipped via line 108-6a to a subtractor 8-12a, shown in FIG. The place of an image factor processed by the arithmetic unit 8-1 might be referred to as hereinafter picture factor point D1 as shown in FIG. 3A. Similarly, different arithmetic models 8-2 through 8-4 are used for computing image element points D2 via D4, and four arithmetic models in whole are used in parallel for concurrent computations for one block. Line memory pair 1-1 and 1-2 and another line memory pair 1-3 and 1-4 are saved and skim out alternately, so that the video sign which is rendered scan conversion i.e. converted into two-dimensional blocks, is output in a string of image parts. One of two outputs from a line reminiscence pair in studying operation is selectively output via the multiplexor 1-5. The block-formation video sign on a line a hundred sa168vip เข้าสู่ระบบ and one from the multiplexor 1-5 branches to the lines 101a and 101b, then is provided to the delay circuit 2a and optimum prediction detector eight, respectively. The above-mentioned scan conversion is advantageous since the predictive coding circuit utilizing the two-dimensional blocks is simple.