Showing papers on "Inter frame published in 1984"

A combined intraframe and interframe transform coding method

Abstract: An apparatus and method for signal processing employing intraframe and interframe variable prediction transform coding. Images are represented by sequential frames of two-dimensional arrays of digital signals. The digital signals are transformed to form transform coefficients for each frame. Predicted transform coefficients are formed using sets of variable prediction factors. The predicted transform coefficients for each frame are compared with corresponding actual transform coefficients for the frame to form transform coefficient difference signals. The difference signals are processed to control their range of values. The processed difference signals are statistically coded such that the more frequently occurring values are represented by shorter code lengths and the less frequently occurring values are represented by longer code lengths. The coded signals are stored in a buffer memory for transmission.

Movement Compensated Interframe Prediction for NTSC Color TV Signals

Abstract: This paper presents techniques for interframe prediction of color NTSC signals using motion estimation and compensation techniques. A key element in movement-compensated prediction is the displacement estimation algorithm. A number of techniques for performing this estimation have been presented in the literature [1]-[13]. Some new techniques giving improved performance are presented in this paper. Also, a movement-compensated composite prediction approach for coding of the NTSC color signals is presented. The performance of different displacement estimation algorithms is evaluated and compared for both component and composite approaches. A database of several color NTSC video sequences is used in the evaluation.

Motion compensated predictive coding

Abstract: Motion compensated predictive codingS. Kappagantula and K. R. RaoDepartment of Electrical Engineering, The University of Texas at ArlingtonP.O. Box 19016, Arlington, Texas 76019AbstractInterframe image coding techniques in real -time provide a very attractive scheme of reduc-ing the bandwidth required for coding and transmitting natural video scenes. This paper pro-poses a modification of two existing algorithms for motion compensated interframe coding.It is shown that the modified method involves a reduced computational complexity while beingcompatible with the performance obtained by the previous algorithms. Implementation of thenew algorithm is consequently simplified and a design for the hardware using a parallelprocessing approach is studied. The system is proposed for use in NTSC TV pictures forapplications ranging from broadcast quality TV to video teleconferencing systems.IntroductionInterframe techniques in image coding present one of the most attractive schemes ofexploiting redundancy in natural video scenes. Conventional interframe techniques were fora long time restricted to coding the television image in terms of clusters of interframedifferences. Here each current frame is compared with the previous frame and only the dif-ferences are coded and transmitted. The receiver simply adds these differences to a copy ofthe previous frame that it has stored. This method has been shown to achieve reductions ofthe order of a factor of 10 over full bandwidth transmission. However as the televisionpicture displays increasing amounts of motion, the coding efficiency of this technique fallsoff rapidly. Such a deficiency makes the method unsuitable for TV transmission at very lowbit rates. Typical TV scenes involve motion details in particular sections of the imagewhile other areas can be said to be 'stationary' or unchanging areas. Moreover the motiondetail that the picture contains, varies with different pictures. Interframe motion compensa-t4.on techniques have therefore evolved2-4,6 -21 where the motion of each pel of a new frame(or a group of pels) is 'predicted' from the information available in the previous frame.Motion compensated predictj,o19L §chemes of this sort can be divided into two types pelrecursive algorithms (PRA) and (ii) block matching algorithms (BMA).

Motion detecting circuit utilizing inter-frame difference signals of successive fields

Abstract: A motion detecting circuit suitable for detecting object-movement on an interlaced TV signal includes at least three field memories, subtracters, absolute circuits and an adder circuit. The motion detector evaluates object-movement by accumulating frame difference signals between adjacent fields.

Video Compression Using Conditional Replenishment and Motion Prediction

Abstract: A study of a low-rate monochrome video compression system is presented in this paper. This system is a conditional-replenishment coder that uses two-dimensional Walsh-transform coding within each video frame. The conditional-replenishment algorithm works by transmitting only the portions of an image that are changing in time. This system is augmented with a motion-prediction algorithm that measures spatial displacement parameters from frame to frame, and codes the data using these parameters. A comparison is made between the conditional-replen-ishment system with, and without, the motion-prediction algorithm. Subsampling in time is used to maintain the data rate at a fixed value. Average bit rates of 1 bit/picture element (pel) to 1/16 bit/pel are considered. The resultant performance of the compression simulations is presented in terms of the average frame rates produced.

The Effectiveness and Efficiency of Hybrid Transform/DPCM Interframe Image Coding

Abstract: We seek to evaluate the efficiency of hybrid transform/ DPCM interframe image coding relative to an optimal scheme that minimizes the mean-squared error in encoding a stationary Gaussian image sequence. The stationary assumption leads us to use the asymptotically optimal discrete Fourier transform (DFT) on the full frame of an image. We encode an actual image sequence with full-frame DFT/DPCM at several rates and compare it to previous interframe coding results with the same sequence. We also encode a single frame at these same rates using a full-frame DFT to demonstrate the inherent coding gains of interframe transform DPCM over intraframe coding. We then generate a pseudorandom image sequence with precise Gauss-Markov statistics and encode it by hybrid full-frame DFT/DPCM at various rates. We compare the signal-to-noise ratios (SNR's) of these reconstructions to the optimal ones calculated from the rate-distortion function. We conclude that in a medium rate range below 1 bit/pel/frame where reconstructions for hybrid transform/ DPCM may be unsatisfactory, there is enough margin for improvement to consider more sophisticated coding schemes.

The relationship between space and time in the perception of stimuli moving behind a slit

Abstract: When a shape defined by a set of dots plotted along its contour is presented in a sequence of frames within the boundaries of a slit, and in each frame only one dot (featureless frame) or two dots (feature frame) are displayed, a whole moving dotted shape is perceived. Masking techniques and psychophysical measures have been used to show that a dynamic random-dot mask interferes with shape identification, provided the interframe interval is greater than about 15 ms, and there are no stimulus features for recognition in individual frames. A similar pattern of results was obtained when the observer had only to detect the movement of a single dot or a pair of dots against a dynamic-noise background. It is concluded that the visual system can resolve the correspondence problem in both apparent movement (one moving dot) and aperture viewing (featureless-frame condition) by extracting motion before the extraction of features in each frame. However, the results also show that where feature identification in each frame is possible, it can also be used to identify the moving targets.

Interframe vector encoder

Abstract: PURPOSE:To prevent vector quantized errors from accumulation by inserting an LPF into an output of frame memory and vector-quantizing a block of a picture signal channel instead of that of a predicted error signal when the corelation between continuous pictures becomes extremely small. CONSTITUTION:A digitized picture signal channel 1 is the sample which is given in the order of the raster scanning direction. The signal channel 1 is sent to a raster/block convertor circuit 2, partitioned into several blocks, and scanned and converted into blocks in the order in which these block are units. Assuming that a picture signal channel 3 which is made into blocks in the fth frame, and a prediction signal channel 44 are channels Sf and Pf, respectively the channel Pf is a signal obtained by removing a high and from the channel 3 of a signal source vector and a reproducing signal of the block in the same position as that of previous one-frame period. Since vector-quantized errors appear in a high band such as granular noises, low-pass filter LPF43 prevents these quantized errors from accumulation; therefore pictures having high quality can be obtained without fail.

Encoder of inter-field and interframe with dynamic compensation

Abstract: PURPOSE:To code efficiently both static and dynamic pictures by detecting each dynamic vector between adjacent frames and fields of a TV picture and selecting one of two kinds of dynamic vectors to generate a forecast signal by using a selected dynamic vector. CONSTITUTION:A TV signal A/D-converted is inputted to a delay circuit 3 and the 1st and 2nd vector detectors 31, 35 from a terminal 1, a difference between an output of the circuit 3 and a forecast error signal from a selector 29 is obtained by a subtractor circuit 5 and inputted to a quantizer 7. Further, the detector 31 detects a dynamic vector with a preceding field outputted from a frame memory 18, the detector 35 detects the dynamic vector of the interframe, and the result of detection is inputted respectively to a discriminating circuit 37 and a selector 33. The circuit 37 supervises the forecast of interfield and interframe, decides those for the next block according to the switching rules and the result is applied to the selector 33. Further, the selector 33 selects any one dynamic vector and oututs a forecast signal.

Inter-frame encoding/decoding equipment provided with a system for detecting a transmission error

Abstract: An inter-frame encoding/decoding equipment for television signals consists of inter-frame encoding equipment encoding a difference between television signals and the output of a frame memory and inter-frame decoding equipment which receives an encoded signal sent from the inter-frame encoding device via a transmission line, which decodes by adding the output of the frame memory to the encoded signal. The inter-frame encoding equipment is provided with a first operation circuit which operates the remainders obtained by dividing, by a predetermined value, the number of bits of logic "1" in the bit groups into which the output or the input of the frame memory is divided by a predetermined unit. The inter-frame decoding equipment is provided with a second operation circuit which operates the remainders obtaiend by dividing, by a predetermined value, the number of bits of logic "1" in the bit groups into which the output or the input ot the frame memory is divided by a predetermined unit. The inter-frame decoding equipment is further provided with a comparator circuit which compares and checks the values operated by the first and the second operation circuits to detect a transmission error.

Digital video transmission at 34 Mbit/s using bit rate reduction techniques

Abstract: Describes the basic principles of a digital television system which has been designed and implemented at the Telecommunication and Microwaves Laboratory of the Universite Catholique de Louvain. The aim of this system was to reach bit rates of the order of 34 Mbit/s. To achieve this, the system uses component coding, expands the signal by removing horizontal blanks, and carries out a combined interframe interpolation and Hadamard transform which roughly equals the vertical and horizontal resolutions. After bit allocation, the signal is converted into a serial stream of data and transmitted. The inverse operations are made at the receiver, where a 625 lines picture is restored. Those principles were implemented and experimented on a transmission via OTS Satellite. Prospects discussed include several sound channels and teletext capabilities and improvements with use of a reduced frame memory.

System and apparatus of coding and decoding between dynamic compensating frames

Abstract: PURPOSE:To improve coding efficiency by estimating optimum prediction in a present picture element from the state of a reference picture element. CONSTITUTION:A predicting function is counted individually, where the dynamic compensation interframe prediction and the interframe prediction take an optimum value in a picture element corresponding to an existing picture element for each state of a reference picture. It is estimated that the interframe prediction is the optimum prediction of the existing picture element in the reference picture element state where the probability P1 taking the interframe prediction as the optimum predicting function is large (P1>=0.5) and the dynamic compensating interframe prediction is the optimum prediction in other reference picture element states in each state obtained by the measurement like this, and the result is used as the prediction to the existing picture element. Since the method estimating the optimum prediction is executed even at the receiving side, it is not necessary to transmit the information which of the dynamic compensating interframe prediction and the interframe prediction is used.