Showing papers on "Inter frame published in 1990"

The cross-search algorithm for motion estimation (image coding)

Abstract: A fast block-matching algorithm for motion estimation is presented. It is based on a logarithmic step where, in each search step, only four locations are tested. For a motion displacement of w pels/frame, this technique requires 5+4 log/sub 2/w computations to locate the best match. Using sequences of CIF standard pictures, the interframe motion compensated prediction error with this technique is compared to the other fast methods. The computational complexity of this algorithm is also compared against those methods. >

Motion dependent video signal processing

Abstract: In, for example, a motion compensated video standards converter (Figure 1) blocks in a first field or frame of a video signal are each compared (3) with a plurality of blocks in the following field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the following field or frame, a correlation surface is generated (3) for respective blocks in the first field or frame, the correlation surface representing the difference between the content of the block in the first field or frame and the content of each block in the following field or frame with which it has been compared, the correlation surface is tested (21, 22, 23) for a clear minimum, the size of the blocks is increased (20) to generate new correlation surfaces, each new correlation surface is tested (21, 22, 23) for a clear minimum, and motion vectors are derived (27) in dependence on the clearest minimum so found

Blockmatching motion estimation algorithms-new results

Abstract: An efficient method for block-matching motion estimation is considered for interframe motion-compensated prediction of video signals. In contrast to other block-matching methods, this approach takes into consideration the behavior of individual pels in the search to find the best match. This is achieved by classifying each pel in the block into one of the categories of matching pel or mismatching pel. The best match within a search area is the block with the highest number of matching pels. In the simulation results presented the scheme is compared with other well-known block-matching schemes. It is found that this method performs significantly better than a scheme such as mean absolute difference (MAD), with lower computation cost. >

Variable size block matching motion compensation with applications to video coding

Abstract: Indexing term: Codes and decoding: Algorithms Abstract: In block matching type motion com- pensation schemes, the image is divided into blocks of the same size. For each block a search is conducted in the previous frame to locate the best correspondence. For the scheme to succeed an implicit assumption has to be made that the motion within each block is uniform, an assump- tion which may not necessarily be correct, and as a result the quality of the prediction suffers. In the paper, a new motion compensation scheme based on block matching is presented, where the size for each block is variable. The proposed algorithm adaptively divides the image into blocks of vari- able size to meet the assumption on uniform motion for all blocks. The scheme has been suc- cessfully applied to simple interframe video coding. It is shown that the proposed algorithm can be extended to form the basis of a complete and efficient codec with low complexity. The possibility of the combination of the scheme with novel hybrid coding techniques to form sophisti- cated systems with low bit-rate performance, that compare favourably with other existing schemes, is also demonstrated.

Moving image signal encoding apparatus and decoding apparatus

Abstract: A moving image signal encoding apparatus includes: a frame decimating circuit for extracting . .encoded.!. frames from an input moving image signal at specified intervals; a frame interpolating circuit for obtaining an interpolated frame between the . .encoded.!. .Iadd.extracted .Iaddend.frames, and a circuit for obtaining an error formed by frame interpolation. A moving image signal decoding apparatus includes: a receiving circuit for extracting a frame code from an inputted signal; a frame decoding circuit for decoding the frame code to obtain a reproduced frame, and a frame interpolating circuit for obtaining an interpolated frame between the reproduced frames. By transmitting an error of the interpolated frame from the encoding apparatus to the decoding apparatus and correcting the error of the interpolated frame with the decoding apparatus, the error of the interpolated frame is eliminated. Alternatively, depending on the value of the error of the interpolated frame obtained with the encoding apparatus, a circuit determines the operation mode as to whether the frame interpolating circuit of the decoder carries out frame interpolation or preceding value holding and sends a flag to show the operation mode to the decoder, so that improvement occurs when the error of the interpolated frame is large.

Apparatus for adaptive inter-frame predictive encoding of video signal

Abstract: An adaptive predictive encoding apparatus for encoding a video signal by utilizing correlation between frames in both the forward and reverse directions of the time axis. A prediction signal for use in deriving prediction error values to be encoded for a frame is selected by an adaptive prediction section, in units of blocks, from a plurality of mutually differently derived prediction signals, in accordance with the degree of correlation of the block with corresponding ones of a specific preceding independently encoded frame and a specific succeeding independently encoded frame. .Iadd.A complementary adaptive decoding apparatus receives the encoded information and reconstructs the video signal in accordance with information supplied to the adaptive decoding apparatus by the encoding signal. .Iaddend.

Video signal transmitting system

Abstract: Video signal transmitting system in which digital video signal are divided into groups of predetermined frames. Digital video signals of at least one frame of them are intraframe coded and then transmitted. Remaining digital video signals are interframe coded with reference to the digital video signals, intraframe coded, and the digital video signals, intraframe coded, of a subsequent group of frames and are then transmitted. A motion vector from a predetermined reference frame is detected. Video signals are interframe coded by the motion vector to transmit the video signals. A motion vector from a frame which is frames away from the reference frame is converted to motion vector per one frame between the reference frame and the frame, is optimized, and is then transmitted.

Inter-frame predictive encoding system with encoded and transmitted prediction error

Abstract: In an inter-frame predictive encoding system, reference frames are set The reference frames are separated at equal intervals The reference frames are selected from successively inputted frames of a video signal Each of the reference frames is encoded A prediction signal for a dependent frame between the reference frames is generated on the basis of a signal of the reference frames which precedes and follows the dependent frame respectively A signal of the dependent frame is generated on the basis of the prediction signal corresponding thereto An error of the predicting of the signal of the dependent frame is encoded IaddA complementary decoding system reconstructs the video signal from the encoded reference frames and the encoded error Iaddend

Apparatus for inter-frame predictive encoding of video signal

Abstract: An inter-frame predictive encoding apparatus which derives a prediction error signal representing successive frames of a video signal based on differences between pixel data of each frame and pixel data of at least one other frame, and executes intra-frame encoding of the prediction error signal, in which the prediction error signal is transferred through a spatial filter prior to intra-frame encoding, and in which the degree of filtering is controlled fixedly or varying in units of frame intervals by a control signal, for thereby controlling the high frequency components of the error signal to an appropriate level in accordance with respective requirements for the output data rate from the apparatus and spatial resolution of a finally obtained picture.

Video encoding method for television applications

Abstract: Continuously monitoring successive frames of a video signal and deciding, based on the similarity between the frames, whether to encode one of them with low or high information content, i.e., as a "low-resolution" frame or a "high-resolution" frame, and whether to encode the next transmitted frame as a low- resolution frame or as a high-resolution frame, and, when sending a high-resolution frame, determining whether to transmit an indication to re-display the past frame or to transmit an indication to display the high-resolution frame as a representation of the present frame. The compression method provides efficient compression of a video signal. A single future frame embodiment allows up to a doubling of the number of pixels transmitted through a channel. With multiple frame systems, even higher compression ratios are possible. Further improvements in compression ratios may be obtained by compressing the individual frames.

Moving image signal encoding- and decoding apparatus

Abstract: A moving image signal encoding apparatus comprises a frame decimating circuit for extracting encoded frames from an input moving image signal at specified intervals, a frame interpolating circuit for obtaining an interpolated frame between the encoded frames, and a circuit for obtaining an error formed by frame interpolation. A moving image signal decoding apparatus comprises a receiving circuit for extracting a frame code from an inputted signal, a frame decoding circuit for decoding the frame code to obtain a reproduced frame, and a frame interpolating circuit for obtaining an interpolated frame between the reproduced frames. By transmitting an error of the interpolated frame from the encoding apparatus to the decoding apparatus and correcting the error of the interpolated frame with the decoding apparatus, the error of the interpolated frame is eliminated. Alternatively, depending on the value of the error of the interpolated frame obtained with the encoding apparatus, circuit determines the operation mode as to whether the frame interpolating circuit of the decoder carries out frame interpolation or preceding value holding and sends a flag to show the operation mode to the decoder, so that improvement is given when the error of the interpolated frame is large.

Adaptive interframe prediction coded video communications system

Abstract: At the transmit end of a video communications system, a first motion vector is derived from successive frames during a frame transmit mode and a second motion vector is derived during or immediately following a frame discard mode. An interframe predicted error signal is generated which is representative of the difference between each input frame and a motion-compensated, previous frame during the frame transmit mode, the difference being zero during the frame discard mode. The predicted error signal and the vectors are transmitted to the receive end of the system. In a first embodiment, the second motion vector is derived at the transmit end from frames spaced apart by a discarded frame, and at the receive end, original frames are recovered from the predicted error signal as well as from the first and second motion vectors, and the second motion vector is down-scaled and evaluated whether it is valid or not. During frame discard mode, motion compensation is performed on the recovered frame using the down-scaled vector in response to a valid evaluation, but no compensation is performed if invalid evaluation is made. In a second embodiment, the second motion vector is derived at the transmit end from successive frames using a larger block size than that used in the first motion vector. At the receive end, the first motion vector as well as the error signal are used in recovering original frames. During the frame discard mode, the second vector is simply used for motion compensation.

Video signal coding method

Abstract: In a method for encoding successive frames of a digital motion video signal in the form of compressed digital data including an intraframe coded signal and a plurality of interframe coded signals, a first frame of the digital motion video signal is encoded to form one of an intraframe coded signal and an interframe coded signal to produce a compressed digital signal; the compressed digital signal is decoded to form a decoded signal; a plurality of predicted video signal frames are produced representing a second frame of the digital motion video signal other than the first frame, at least one of the plurality of predicted video signal frames being produced with the use of the decoded signal and a motion vector representing motion between frames of the digital motion video signal; the plurality of predicted video signal frames are compared with the second frame of the digital motion video signal for producing a plurality of difference data each corresponding with a respective one of the plurality of predicted video signal frames; one of the predicted signal frames having a smallest corresponding difference data is selected; and an interframe coded signal of the compressed digital data corresponding to the selected one of the predicted video signal frames is generated.

Extended structure and motion analysis from monocular image sequences

Abstract: The issue of optimal motion and structure estimation from monocular image sequences with a rigidity scene is addressed. The method has the following characteristics: the dimension of the search space in the nonlinear optimization is drastically reduced by exploiting the relationship between structure and motion parameters; the degree of reliability of the observations and estimates is effectively taken into account; the proposed formulation allows arbitrary interframe motion; and the information about the structure of the scene, acquired from previous images, is systematically integrated into the new estimations. It is shown that any scale factor associated with two consecutive images in a monocular sequence is determined by the scale factor of the first two images. The simulations and experiments with long image sequences of real world scenes indicate that the optimization method developed greatly reduces the computational complexity and substantially improves the motion and structure estimation over that produced by linear algorithms. >

Method and apparatus for transmitting a compressed picture signal by using different encoding techniques for portions of each frame

Abstract: Intraframe coding and interframe coding are selectively employed for generating a compressed digital video frame in order to record a motion video signal on a small capacity recording medium such as a CD ROM. Motion compensation is also employed for effective compression, and motion compensation in only one direction is applied to an area of the frame in which interframe coding is applied that corresponds to an area of a previous frame in which the intraframe coding was applied.

Inter-frame predictive encoding system

Abstract: In an inter-frame predictive encoding system, reference frames are set. The reference frames are separated at equal intervals. The reference frames are selected from successively inputted frames of a video signal. Each of the reference frames is encoded. A prediction signal for a dependent frame between the reference frames is generated on the basis of a signal of the reference frames which precedes and follows the dependent frame respectively. A signal of the dependent frame is generated on the basis of the prediction signal corresponding thereto. An error of the predicting of the signal of the dependent frame is encoded.

Method for storing and reproducing video signals

Abstract: A method for storing and reproducing video signals is described, the picture information of which is structured into video frames. As a means for carrying out such a method, a known hybrid coder can be used which codes the video data coming from a video data source either in accordance with the intraframe principle or the interframe principle for reducing the bit rates. So that the hybrid decoder connected between memory and monitor does not need to run at a higher speed than normal during a fast check (fast forward or fast rewind) it is provided to code a prescribed section, which can be recognised again in isolation, of predetermined video frames in accordance with the so-called intraframe principle during the storage. During an accelerated check of the stored picture information, the prescribed sections are read out and only these are decoded and reproduced on the monitor.

Video frame reduction/reconstruction method and apparatus

Abstract: A method and apparatus for reducing the amount of video information which is transmitted to a receiver, while still enabling the receiver to reconstruct a representation of the original video source material. In a preferred embodiment, a 60 frames per second progressively scanned video signal is transmitted at a 30 frames per second rate accompanied by decoding information. In short, every other frame is deleted and a respective nearest neighbor is selected to represent the deleted frame. This selection is represented by a digital selection information. Thus the transmitted frame information can be reconstructed into the original video source material after decoding with the digital selection information.

Motion-compensated interframe prediction

Abstract: Motioncompensated interframe prediction has been applied widely in digital television signal coding specially in low bit-rate coding such as videotelephone and videoconference. A key element in motion-compensated interframe prediction is the motion estimation algorithm. In this paper a new motion estimation algorithm is presented. It is based on the block recursive (gradient) method and makes use of some of the advantages of the blockmatching method. Motion estimation with non-integer pd accuracy can be obtained with only a few iterations. In addition some techniques with respect to motion correlation and motion tendency estimation which we proposed before [1] are applied to the estimation algorithm which are efficient enough to improve the performance of the motion estimation and the homogeneity of the estimated motion vector field. The experiment shows that the proposed algorithm has a much higher estimation accuracy and a much better prediction performance than the conventional block motion estimation algorithms. Moreover a coding approach designed effectively to minimize the bit-rate necessary to present the motion vector field is proposed as well. A high compression rate for the transmission of the motion information has been achieved. Finally the simulation results of motioncompensated interframe prediction for low bit-rate coding based on the proposed algorithm and of the motion information encoding are presented.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Adaptive inter-frame prediction encoding system

Abstract: PURPOSE:To prevent pictures from being mixed together by setting an independent frame in advance at a prescribed interval, mixing frames inbetween adaptively and encoding the result with a mixture ratio so that a prediction signal by frames between both preceding and succeeding independent frames has the highest prediction efficiency CONSTITUTION:A moving picture signal inputted from a picture signal input terminal 1 is connected to the position (a) of a changeover switch 2 for independent encoding processing in a frame per N frames A signal in the in-frame processing is converted into a coefficient component at an orthogonal converter 6 at first to obtain a higher encoding efficiency with the orthogonal conversion method such as the discrete cosine transformation in the unit of about 8X8 picture element block The converted signal is quantized at a proper step at a quantizer 7 for each coefficient component Then the signal is converted into a variable length code such as a Huffman code with a variable length encoder 8 and outputted from a data output terminal 9 as a variable length digital data and recorded or transmitted

Inter-frame video filter having selective linear and non-linear transfer characteristics as function of inter-frame differences

Abstract: Temporarily filtered video samples are formed as the sum of a previous frame output sample and a non-linear function of the difference between current and previous samples. The function is non-linear only for absolute values of differences less than 50% (preferably 10%) of the maximum range of the difference, and a smaller lookup table is used for implementing the non-linear function than would otherwise be the case.

Subband coding of video with adaptive vector quantization

Abstract: A low bit rate adaptive video coding technique is proposed. The redundancy within adjacent video frames is exploited by motion-compensated interframe prediction, and the motion-compensated frame difference (MCFD) signal is decomposed by using a quadrature mirror filter (QMF) structure. The subband signals are vector quantized adaptively. The MCFD signals are low correlated, hence transform coding techniques are not very suitable for this kind of signal source. At 0.25-0.3 bits/pixel range, 38-40-dB peak-to-peak signal-to-noise ratio is achieved with the proposed scheme for four monochrome test sequences used: cindy, mono, duo, and quartet. The visual quality of the encoded test sequences is good, almost indistinguishable from the originals. The proposed technique outperforms the adaptive transform coding and adaptive vector quantization techniques for the tested sequences. >

A variable bit rate layered DCT video coder for packet switched (ATM) networks

Abstract: A combined inter/intra-frame discrete cosine transform (DCT) with layered transmission of (significant) coefficient sets is proposed. In the scheme, a whole frame is either intraframe or interframe coded based on the amount of motion. In the interframe mode, a vertical strip, which cycles periodically to refresh a section of the frame, is intraframe coded. This refresh feature preserves the synchronization in the event of cell loss. The layered transmission of the coefficients allows delivery of the desired quality video, after low-energy (layered) coefficients are selectively discarded, and immunity to cell loss is achieved by utilizing the correctly received layers to compensate for the effects of lost cells in reconstructing the frame blocks. >

Motion vector replensihment for low bit-rate video coding

Abstract: A low bit-rate video codec based on motion vector replenishment is described. Motion vectors are used to update pictures at full frame rate. In addition, part of each frame is conditionally updated with a strip of interframe video data. The video data fill the remaining channel capacity not used for motion vectors. Thus under most conditions, each frame is fully updated by motion vectors and partially with interframe video data. This method has a comparable compression efficiency with that of the frame dropping method, but does not introduce any picture ‘jerkiness’. Finally the application of the proposed method to packet video networks is examined.

Adaptive frame interpolation system for inter-frame prediction decoder with movement compensation

Abstract: PURPOSE:To prevent deterioration in picture quality caused in the case of interpolation through the use of an erroneous moving vector by using selectively a method of interpolation to an interleaved frame through the use of a moving vector based on a predetermined criterion and the method of interpolation with other method not using a moving vector. CONSTITUTION:A means 105 which uses a predicted error signal 107 in a moving vector block from an inter-frame prediction decoding section 102 with moving compensation for each moving vector detection block, calculates an evaluation from a moving vector evaluation section 103 based on the predetermined evaluation function, compares the result of calculation with a predetermined threshold level and interpolates the interleaved frame through the use of the moving vector, and a means 104 interpolating the frame through the use of preceding and succeeding frames of the interleaved frame are used selectively to move Jarkieness due to frame interleaving while deterioration in the picture quality due to the interpolation of the moving vector caused due to inaccurate moving vector is suppressed.

Subband based CCITT compatible coding for HDTV conferencing

Abstract: A motion-compensated interframe subband coding algorithm suitable for a wide range of video coding applications is described. In this approach, the spectrum of each frame of video signals is first decomposed into smaller frequency bands in which each can be coded accordingly. For the best performance a combination of hybrid pulse-code modulation discrete cosine transform/differential pulse-code modulation (DCT/DPCM), interframe DPCM, and interframe pulse-code modulation (PCM) was considered. The subband coder is designed to encode the video in two separate layers for a dual-quality video representation. Simulations were performed using HDTV sequences as input. For two-layer structure coding, results are given at an average rate of 1.5 Mb/s for the basic layer and 5.62 Mb/s for the full HDTV resolution. Statistical multiplexing using two-level scheduling/priority is also considered and the effect of cell dropping on the quality of the reconstructed video signal is investigated. >

Inter-frame coding decoding system

Abstract: PURPOSE:To allow a coding section and a decoding section to detect the same moving vector and to reduce the information quantity to be sent with only a difference value of a transmission signal by using a one or two preceding frame for the moving detection. CONSTITUTION:When a picture signal is inputted to an inter-frame coding means 1, a signal delayed by one frame is outputted to moving vector detection means 2. The means 2 detects a moving vector of an object from the signal and a two preceding frame signal being the result of one frame delay and outputs the result to the means 1. The means 1 generates a prediction signal according to the processing above, detects a difference from a picture signal and sends the result to a decoding section via a transmission line. An inter-frame decoding means 3 and a moving vector detection means 4 of a decoding section generate a prediction signal from signals retarded by one and two frames and the moving vector, add the signals to the difference value from the transmission line to reproduce the picture signal.

Encoding of videoconferencing signals using VDPCM

Abstract: The techniques of motion detection, interframe linear block prediction and vector quantization have been incorporated in this paper, in a scheme for encoding monochrome image sequences for videoconferencing application. Data transmission rate reduction is accomplished by identifying and processing only those regions that exhibit noticeable changes between successive frames, by estimating the magnitude of the change through linear block or vector prediction and quantizing the residual vectors through a vector quantizer. The motion detector uses a modified block matching algorithm to detect the moving blocks. Perceptually-based edge detectors are used to design vector quantizer (VQ) codebooks for different classes of image blocks to achieve better visual quality. Encoding rates under 60 kbps are achieved with acceptable visual quality at nominal computational complexity.

Format conversion of digital video signals

Abstract: In order to convert an input 60 field/s 2:1 interlace scan format digital video signal (col. A) into an output 30 frame/s progressive scan format digital video signal (col. G), a progressive scan format frame (col. D) is produced for each input field using intrafield interpolation and/or interframe interpolation, and each output frame is produced by motion compensated interpolation between a pair of successive progressive scan format frames.

Apparatus for adaptive interframe predictive decoding of a video signal

Abstract: An apparatus for adaptive inter-frame predictive decoding of a video signal which comprises a plurality of spaced-apart reference frames and dependent frames located therebetween and encoded as a function of the immediately preceding and succeeding reference frame. A prediction mode signal is also transmitted and used on decoding to recreate the dependent frames as a function of the adjacent reference frames.