Showing papers on "Inter frame published in 1987"

An Adaptive Algorithm for Motion Compensated Color Image Coding

Abstract: This paper presents an adaptive algorithm for motion compensated color image coding. The algorithm can be used for video teleconferencing or broadcast signals. Activity segmentation is used to reduce the bit rate and a variable stage search is conducted to save computations. The adaptive algorithm is compared with the nonadaptive algorithm and it is shown that with approximately 60 percent savings in computing the motion vector and 33 percent additional compression, the performance of the adaptive algorithm is similar to the nonadaptive algorithm. The adaptive algorithm results also show improvement of up to 1 bit/pel over interframe DPCM coding with nonuniform quantization. The test pictures used for this study were recorded directly from broadcast video in color.

A Motion Picture Coding Algorithm Using Adaptive DCT Encoding Based on Coefficient Power Distribution Classification

Abstract: A motion picture coding algorithm using motion-compensated interframe prediction and the adaptive discrete cosine transform (DCT) encoding technique is proposed. High coding efficiency is obtained by the adaptive DCT encoding technique in which encoding parameters are fitted to widely varying characteristics of the interframe differential signal. Segmented DCT subblocks of interframe prediction error are classified into categories based on their coefficient power distribution characteristics. The adaptation gain results from using a suitable variable word length code set designated by the above classification for encoding each quantization index of DCT coefficients. In addition, a new coding parameter control method is introduced based on the information rate estimation of the current frame. This classification promotes high stability because good estimation accuracy of bits consumption for each DCT subblock is obtained by utilizing the category indexes. Simulation results show that the proposed algorithm has enough coding efficiency to transmit videoconferencing motion pictures through a 384 kbit/s channel.

Motion-Compensated Coder for Videoconferencing

Abstract: A codec for videoconferencing purposes [8]-[12], [31] is proposed based on the one-at-a-time search (OTS) motion compensation algorithm [1], [30], [31]. The coder is implemented in an interframe hybrid mode using the C -matrix transform (CMT) [13]-[15]. The motion estimation algorithm employed is simple and reduces temporal redundancy, while the CMT reduces spatial redundancy in the transmitted prediction errors. The operation of the codec is presented. Simulation results based on three different scenes with varying levels of motion are presented. The coder operates in a feedback mode.

Data compression using orthogonal transform and vector quantization

Abstract: "Data Compression Using Orthogonal Transform and Vector Quantization" ABSTRACT OF THE DISCLOSURE In an image communication system, an input image sequence is converted into a block-formatted sequence. data compression signal indicative of the amount of moving blocks in the block-formatted sequence is generated to individually control a plurality of vector quantizers each having a particular frequency band and a memory containing output vectors. The output vectors of each of the vector quantizers is representative of inverse orthogonal transform of a code table of optimum quantized vectors in the particular frequency band, the optimum quantized vectors being orthogonal transform of interframe differential training image sequences. The output vectors is retrievable from the memory as a function of an interframe differential image sequence, or prediction error. Each vector quantizer selects one of the vectors retrieved from the memory which is nearest to the value of the interframe differential image sequence and generates an index signal representative of the selected vector, which index signal is encoded and transmitted to a destination. The outputs of the vector quantizers are processed by inverse vector quantizers to generate a predictive image sequence. The prediction error is detected as a difference between the predictive image sequence and the block-formatted sequence.

System for coding and transmitting motion image signals

Abstract: A motion compensation difference interframe or intra-frame coding system includes a block data redundancy compression and coding unit, a PIXEL data coding unit and a prediction data generator unit. The block data redundancy compression and coding unit codes a motion compensated (MC) difference between an input image in a block and a motion predicted image from the prediction data generator unit, and transmits coded data to a receiver. The PIXEL data coding unit receives an error between the MC difference and a decoded MC difference from the block data redundancy compression and coding unit, rearranges the error in PIXEL data and codes the PIXEL error, when the error is greater than a predetermined value. The PIXEL coded data is also transmitted to the receiver. The prediction data generator unit generates predicted block data of the motion of the image. The redundancy compression and coding unit may include a filter circuit rejecting pulse components contained in the MC difference.

A finite-state vector quantizer for low-rate image sequence coding

Abstract: Vector quantization (VQ) is an effective spatial domain image coding technique at under 1.0 bits per pixel (bpp). Its performance can be improved by incorporating block-to-block memory. Finite State VQs (FSVQ) do this by using a state variable to express characteristics of neighboring blocks and identify which subset of a supercodebook the FSVQ encoder and decoder are to use for the current vector. This paper describes a new method for image sequence coding that uses an interframe FSVQ In the spatial domain. Block-to-block and frame-to-frame memory is expressed through a state which is a function of block motion and the intensity gradients of a block's neighbors. A scalar predictor adds additional interframe memory and reduces the energy of residuals encoded by the VQ, improving edge rendition and limiting blocking artifacts. The codec at 0.6 bpp outperforms a similar, non-finite state intraframe VQ at 1.0 bpp. No motion compensation or conditional replenishment is used.

Entropy Coding for a Hybrid Scheme with Motion Compensation in Subprimary Rate Video Transmission

Abstract: Entropy coding has been investigated for motion-compensated interframe (MC) prediction followed by two-dimensional discrete cosine transform (DCT) for prediction error. In particular, variable word length coding methods for motion vector and transform coefficients have been discussed assuming low bit rate such as 384 kbits/s for transmission of videoconference sequences. For motion vector information, it is advantageous to employ a one-dimensional code set common to both horizontal and vertical components of motion vectors. The code set can be obtained using a combined distribution of the two components. In order to encode transform coefficients, different methods are applied to significant and insignificant blocks. Run-length coding is adequate for representing clusters of insignificant blocks. In encoding transform coefficients in significant blocks, a zone coding method which encodes transform coefficients within a minimum area enclosing all nonzero coefficients is suitable. Simulation of video sequences shows that a combination of the coding methods described here can achieve high coding efficiency for videoconference sequences.

Recursive Temporal Filtering and Frame Rate Reduction for Image Coding

Abstract: The effect of temporal recursive filtering and frame rate reduction on a sequence of moving images is investigated. Following a well-known first-order Markov model for the temporal domain data, the effect of filtering and frame rate reduction on the values of variance, correlation coefficient, filtering distortion, and interframe prediction error are mathematically derived. The validity of these derivations is verified by the experimental results using a CCITT standard sequence which closely follows the first-order Markov model. The effect of temporal filtering and frame rate reduction to the coding rate is examined by encoding the CCITT standard sequence using a combined interframe and intraframe Scene Adaptive Coding system. At a frame rate of 30 frames per second, a 2:1 reduction in coding rate is obtained with a filtering coefficient of 0.5. At a frame rate of 10 frames per second, an additional reduction factor of nearly 2 is obtained using the same filtering coefficient. Selected images are presented to demonstrate the subjective effect.

Frame find circuit and method

Abstract: A frame word in a word-interleaved multiplexed serial data stream is detected by latching a word from the data stream and comparing it with the frame word. If there is a match, latching of consecutive words continues for at least one frame to check for the frame word in the next frame. If the compared words do not match, then a bit slip is effected so that the next word latched and compared has a different bit orientation from the preceding word, whereby in one frame words with various different bit orientations are examined for the presence of the frame word, and all possible bit orientations of the words are checked over a number of frames. The arrangement eliminates the need for one counter in the frame find circuit and simplifies its control circuitry.

Video signal transmission system

Abstract: PURPOSE: To realize efficient refreshing by suitably switching and transmitting a refresh mode and an interframe difference encoding mode based on the statistic value of generation information correspondingly to respective blocks. CONSTITUTION: Video data 111 divided to the blocks is decided for every block of a mode switching part 1200 and for every frame based on the effective statistic values of the respective blocks and divided into the data 1201 of an interframe difference mode block and the data 1202 of a refresh mode block. On the block of the refresh mode, for instance, grey level data is formed by a reference data forming part 1240 for the refresh mode or an average value for every block of decoding data is formed or according to the scale of the change of a video signal, these data are combined and applied to a reference data memory 1250. In such a way, the decoding data by integrating the interframe encoding mode and the refresh mode on one frame is formed and outputted as the decoding data of one frame. COPYRIGHT: (C)1988,JPO&Japio

Improved Hybrid Coders With 2D-Signal Processing For Moving Pictures

Abstract: 2D-signal processing techniques for interframe hybrid coders with motion compensating prediction are investigated. "Equivalent" 2D-filters and "equivalent" coder structures are proposed to improve the subjective quality of moving pictures encoded at about 64 to m x 384 kbit/s (m = 1, 2, ..., 5). An optimum predictor is derived and it is concluded that this solution is quite close to the concept of equivalent filters. The complete coding scheme is described.

Method for interframe prediction coding with movement compensation

Abstract: Bie this method for frame-to-frame prediction coding is split an image into a regular block raster with nxn pixels. Then, before each prediction up to four prediction methods, namely: Blockwise displacement vector calculation, Object-related displacement vector calculation, Zeroing of the displacement and Zeroing the prediction checked for the data to be transmitted rate and the one selected method for transmission that results in the least amount of prediction errors.

Method and apparatus for forecast coding and decoding of dynamic compensation inter-frame of picture signal

Abstract: PURPOSE:To reduce information per picture element while suppressing deterioration of picture quality by applying spatial interpolation to a local decoding signal, applying variable delay to the local decoding signal subjected to spatial interpolation according to a minority dynamic vector to form a forecast signal. CONSTITUTION:In detecting a dynamic vector, minute movement not detected before spatial interpolation is detected by applying spatial interpolation to a picture signal with deteriorated spatial resolution. After a local decoding signal is subjected to spatial interpolation, a few picture elements are retarded according to the minority dynamic vector. Then spatial interleaving is applied to restore the resolution to the resolution before spatial interpolation and the result is used as a forecast signal. Thus, in comparison with the application of the conventional block matching dynamic compensation inter-frame forecast coding and decoding method, the dynamic vector is detected in detail and more suitable forecast is applied, then the value of the forecast error signal is decreased and the information quantity per picture element is reduced.

Inter-frame coding method

Abstract: PURPOSE:To improve the picture quality even for a limited buffer memory capacity by coding a read sequence of a picture memory from the required part earlier and decoding the signal in the order at the reception side. CONSTITUTION:An animation picture signal is stored to either of frame memories 17A, 17B by changeover switches 16A, 16B at the transmission side 1. Then a data in the frame memory 17A or 17B is read in the order selected by a CPU 20 earlier and sent to a forecast coding circuit 3. The result is sent to a variable length coding circuit 4, subject to variable length coding according to the coded table and sent to the next frame constitution circuit 7. The read sequence is stored and reproduced at the reception side, then the signal is decoded in the predetermined sequence.

Inter-frame adaptive inserting system for dynamic image signal

Abstract: PURPOSE:To improve widely an insertion quality by using adaptively one of a frame insertion, the insertion between action correcting frames and the insertion system between action correcting fields or a load sum by the result of the accuracy of the presumed value of an action quantity. CONSTITUTION:For the contents of field memories FM2, FM3 and FM4, the block is read in which only the presumed value signal of the action quantity is shifted, and by a frame insertion value calculating circuit 5, an insertion value calculating circuit 6 between action correcting fields and an insertion value calculating circuit 7 between action correcting frames, respective insertion values are calculated. A testing quantity alpha is read from respective FM2, FM3 and FM4 by a testing quantity detecting circuit 9, a value (testing quantity alpha), in which the absolute difference sum of all blocks comes to be maximum is obtained by the calculation, inputted to the table of a coefficient calculating circuit 10 and synthesized by a synthesizing circuit 11.

Predictive coding system

Abstract: PURPOSE:To elevate an encoding efficiency, by using an interframe interpolating prediction, as well without limiting a prediction to an inframe interpolating prediction when an input signal is separated into two screens and the screen of one side is predicted from the screen of other side CONSTITUTION:In a first encoding circuit 2, a signal is quantized and outputted by a quantizer Q, but in this case, a predicted signal is generated by an inframe extrapolating prediction circuit P The input signal to the inframe extrapolating prediction circuit P is inputted to a frame memory 31 in an interpolation value generation circuit 3, and is delayed by one frame portion, and further, is delayed by one frame portion by the frame memory 32 Accordingly, in an interpolation circuit 33, an interframe interpolation predicted signal (signal C) is generated from the input signal X to the frame memory 31 and the output signal Y from the frame memory 32 Besides, in this interpolation circuit 33, an inframe interpolation predictive signal (signal C) can be generated, as well from the output of the frame memory 31

Inter-frame decoder

Abstract: PURPOSE:To prevent a random picture from being projected on a receiving picture monitor by outputting the signal of a memory circuit by a selection circuit when a decoder between frames does not receive an encoding signal between the frames. CONSTITUTION:Encoding data between the frames is inputted to an input terminal 1, decoded into a TDM signal in a decoding circuit 4 between the frames and a decoding TDM signal (c), a frame pulse (d) indicating the top of the frame and a signal (d) indicating that the decoding error is not present are outputted. The signal (c) is ordinarily outputted to an output terminal 3 through the selection circuit 7. An FF5 is ordinarily reset and when it is reset by a control signal (e) from an input terminal 2, a timing is taken by the pulse (d) in a register 6 to have the selection signal of the circuit 7 and the circuit 7 selects the signal from the memory circuit 8. At this time, in the circuit 8, since the signal of its own is fed back, the data is not updated but the decoding TDM signal before a signal (g) is changed over is repeatedly outputted and a still picture is projected on the receiving picture monitor.