Abstract: A system and method are disclosed for implementing an encoder suitable for use with the proposed ISO/IEC MPEG standards including three cooperating components or subsystems that operate to variously adaptively pre-process the incoming digital motion video sequences, allocate bits to the pictures in a sequence, and adaptively quantize transform coefficients in different regions of a picture in a video sequence so as to provide optimal visual quality given the number of bits allocated to that picture.

Abstract: Block-by-block motion compensation algorithms are studied for video-conference/video-telephone television signals. A fast feature-based block matching algorithm using integral projections for the motion vector estimation is proposed. The proposed algorithm reduces the motion estimation computations by a factor of two by calculating the one-dimensional cost functions rather than the two-dimensional ones. Also, the low sensitivity of the proposed algorithm to the presence of additive noise is shown experimentally. Simulation results based on the original and noisy image sequences are presented. >

Abstract: A system and method for processing a stream of video image data so as to create a video representation that multiplexes data corresponding to resolution or bitstream scales. This representation is such that the identity of the basic MacroBlock (MB) structure of the MPEG-1 ISO standard is preserved across all resolution and bitstream scales, e.g. by scaling across four levels of resolution. A MacroBlock is associated with a series of attributes which contribute to the amount of overhead data incorporated in an MPEG-1 compressed data stream, so that by preserving the MacroBlock identify across multiple resolutions and bitstream scales, these scales can share this overhead, thus requiring it to be included only once in the data stream. Preserving the MacroBlock identify also simplifies significantly the derivation of motion estimation vector data for all resolution scales other than the highest resolution. Essentially, the motion vector data corresponding to any resolution scales can be derived from the highest resolution motion vector by appropriately scaling it down. Alternatively, the full resolution motion vectors can be derived by appropriate scale up of lower resolution motion vectors. Further, the methodology for coding a MacroBlock is also preserved.

Abstract: The authors develop a new analytic model for a variable bit rate video source, which can model a variety of video applications by a suitable choice of model parameters. Using the model they studied the performance of a video multiplexer that multiplexes several full motion video sources. The video sources were assumed to use a layered coding technique. A service strategy is proposed that guarantees delivery of packets marked essential, whereas nonessential packets may be dropped in the event of congestion. The study showed that with layered coding, good tail probabilities can be obtained for a given number of sources at the expense of some loss for nonessential packets. The performance of the video multiplexer was investigated when the video sources were correlated, and when independent video sources with different thresholds for essential packet rate were multiplexed together. >

Abstract: A system and method of compressing original video data expressed in a plurality of digitally coded frames which enable decompression and playback of resulting compressed video data at one of a plurality of frame rates while maintaining temporal fidelity of the frames displayed. Compression includes selecting a plurality of rate streams for the compressed video data, including a highest rate stream including all of the frames of the original video data and a lowest rate stream including a subset of regularly spaced frames of the original video data. Then the initial frame in the original video data is spatially compressed and the resulting compressed data placed in the compressed video data. The initial frame is also saved as a base frame for all rate streams for subsequent temporal compression of the original video data. As frames are retrieved from the original video data in sequence, temporal compression based on frame differencing techniques between the retrieved frame and the base is carried out, with difference frames being stored to the compressed video data. Each difference frame is placed in the resulting compressed video data for later decompression and reproduction.

Abstract: A video signal encoding apparatus in which the number of quantization bits used in a quantizing circuit is determined on the basis of the activity index of each video block and the length of coded data or alternatively on the basis of the activity index of each video block and the number of events (each event consisting of the zero run length and nonzero value of quantized data). The video signal is encoded in a compressed form after shuffling the video blocks in such a manner that, when attention is given to any given video block, its four neighboring video blocks belong to units different from the unit to which the attention video block belong. Compression encoding of the video blocks is performed in sequence starting with the center of the screen and then proceeding toward the sides of the screen.

Abstract: Digital video signals are processed by a plurality of independently operating processors to provide data for transmission in a compressed, motion compensated form. A video image frame area is divided into a set of subframes. The set of subframes is systematically shifted such that the individual subframes progressively cycle across and wrap around the video image frame area. For each successive video frame, video image data bounded by each of the different subframes is independently compressed using motion estimation to reduce data redundancy among the successive frames. The motion estimation is limited for each subframe of a current video frame to areas of a previous video frame that were bounded by the same subframe in the previous frame. In an illustrated embodiment, the set of subframes is shifted once for each successive video frame, and each subframe includes a refresh region whereby the video image frame area is progressively refreshed as the subframes are shifted thereacross. Receiver apparatus for use in decoding the independently processed subframe data is also disclosed.

Abstract: A video compression system which is based on the image data compression system developed by the Motion Picture Experts Group (MPEG) uses various group-of-fields configurations to reduce the number of binary bits used to represent an image composed of odd and even fields of video information, where each pair of odd and even fields defines a frame. According to a first method, each field in the group of fields is predicted using the closest field which has previously been predicted as an anchor field. According to a second method, intra fields (I-fields) and predictive fields (P-fields) are distributed in the sequence so that no two I-fields and/or no two P-fields are at adjacent locations in the sequence. According to a third method, the number of I-fields and P-fields in the encoded sequence is reduced by encoding one field in a given frame as a P-field or a B-field where the other field is encoded as an I-field and encoding one field in a further frame as a B-field where the other field is encoded as a P-field.

Abstract: A differential pulse code modulation system having bidirectional motion estimation for blocks in bidirectionally-predicted frames, B frames, that is derived from the motion vector of a block in an anchor frame whose projection along its motion vector has the most overlap with the block in the B frame for which a motion estimation is sought.

Abstract: A block matching method for estimating motion contents in a video signal is presented. The motion is represented by a two-dimensional motion vector field, including horizontal and vertical vector components. The method can be used in a wide range of applications, has high spatial and motion vector resolution, is robust under adverse signal conditions, and is cost effective in real-time implementations. The block matching method includes iterative processing with different block sizes from coarse to fine with prediction of motion vectors from surrounding blocks. Resolution of each iteration's block size is preserved at the same resolution as the original input video signal for which the motion vector field is being generated.

Abstract: A data compression system responsive to a preprocessed digitally encoded high definition video signal includes a discrete cosine transform, a frequency weighting filter, and an inverse discrete cosine transform circuit to provide a digitally encoded video signal within which the high frequency terms of the discrete cosine transform have been reduced. A motion compensated predictive coding data compression system organizes the current frame and a previous frame into a plurality of pixel blocks. The pixel blocks are compared by an error calculating and matching circuit under the influence of a timing control to provide an error value output. A spatial weighting factor is applied to each error value output to provide spatially weighted error values which are used to produce a corresponding plurality of motion vectors. The motion vector corresponding to the lowest weighted error value is selected by a motion vector selector for application to a channel buffer/encoder and eventual transmission.

Abstract: The MPEG video coding standard for the transmission of variable-bit-rate video on asynchronous transfer mode (ATM)-based broadband ISDN is examined. The focus is on its use for real-time transmission of broadcast-quality video. The impact of two key parameters, the intraframe to interframe picture ratio and the quantization index that are defined in the standard, on the bit rates per frame was studied. These parameters can be used to control video sources depending on the state of the network. Also, as opposed to previous work which looks only at bit rates per frame, the bits generated per macroblock are studied. This is the basic MPEG coding unit. By packetizing these bits, insight was obtained into the cell arrival process to a network for a MPEG video source. >

Abstract: This paper describes a motion compensated video coding method that employs a simple segmentationscheme to achieve sub-block resolution of the motion field. This increased accuracy of the motion esti-mation reduces the energy of the residue or displaced frame difference by as much as 30%. Including theoverhead to send the side information, the average bit rate is reduced by approximately 10%. 1. INTRODUCTION In block based motion compensated video coding, a frame is divided into non-overlapping blocks ofN * N pixels. For each block, a best match is determined in the previously transmitted frames. The criterion is usually the mean absolute difference (MAD) between the two blocks. The match is subtractedfrom the block to form the displaced frame difference (DFD) or residue which is then compressed by transform coding. The relative position from the block to the matched block in the previous frame is called motion vector. The collection of all the motion vectors forms a motion field.Block based motion estimation assumes that all pixels in a block move by the same amount. When twoor more objects in a block move at different velocities, the motion vector obtained by the conventional blockmatching method may correspond to only one of the objects, or in the worst case, to none of the objects.This can result in large DFD energy. The DFD can be reduced by using smaller block sizes, incurring thecost of sending more motion vectors. Orchard [1] applied segmentation to the previously reconstructedframe by dividing each block into regions corresponding to objects moving at different velocities. Motionestimate of each region is chosen from one of its nearest neighbors, so no extra motion vector needs to besent. However, segmentation adds a nontrivial amount of computation, must be done at both the encoderand decoder, and may not be easy to implement in hardware.In this paper, we present a simple motion field segmentation scheme that achieves sub-block resolution.Simulations show that the DFD energy can be reduced by as much as 30% and the overall bit rate byapproximately 10%.

Abstract: A method and system for video motion compensation (21) in which an overall interframe motion vector is divided into a relative block motion vector and a subblock motion vector. Image reconstruction is achieved by adjusting the delay between the synchronization pulse and the start of the pixel data according to the subblock motion vector, and accessing stored data from memory (42) according to the relative block motion vector. Accessing memory in a block-quantized format ensures that page mode accesses are confined to the same memory row.

Abstract: Block motion compensation is a critical component of most efficient video compression algorithms. Applications range from real-time low bit rate teleconferencing codecs to moderate and high bit-rate coding standards currently being considered for CD-ROM video storage and packet video. Recent research has suggested that blocking artifacts can be reduced by applying block motion compensation on overlapped blocks in image frames. In this paper, we formulate overlapped block motion compensation as an optimal linear estimator of pixel intensities given the neighboring block motion estimate in the frame. Applying this framework, we propose a procedure for designing optimal windows for overlapped block motion compensation. When applying block motion compensation with overlapped blocks, the optimal motion vector to apply at each block in an image depends on values of motion vectors in a non-causal neighborhood of that block. Thus, unlike for standard block-based compensation, optimal motion estimates cannot be computed with exhaustive search block- matching algorithms, even with the overlap window incorporated. Instead, we defined a simple iterative procedure for computing optimal motion estimates for overlapped block motion compensation. The performance gains achieved by both optimal motion estimation and optimal overlapped windows are demonstrated in simulations. Together, reductions of up to 30% in displaced frame difference energy are demonstrated compared with standard block motion compensation.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: A process for coding a plurality of compressed video data streams in a time ordered sequence. Each compressed data stream includes coding of frame to frame differences of a video segment, which are represented as a compressed M×N exclusive-OR plane of pixel change values and location displacement control values for an output pointer into a decompressed video frame. By coding frame to frame differences in an exclusive-OR values, the replay process is made bidirectional, allowing for both forward and reverse playback of the video segment.

Abstract: This paper presents an adaptive error concealment technique for MPEG (Moving Picture Experts Group) compressed video. Error concealment algorithms are essential for many practical video transmission scenarios characterized by occasional data loss due to thermal noise, channel impairments, network congestion, etc.. Such scenarios of current importance include terrestrial (simulcast) HDTV, teleconferencing via packet networks, TV/HDTV over fiber-optic ATM (asynchronous transfer mode) systems, etc. In view of the increasing importance of MPEG video for many of these applications, a number of error concealment approaches for MPEG have been developed, and are currently being evaluated in terms of their complexity vs. performance trade-offs. Here, we report the results of recent work on a specific adaptive algorithm that provides excellent robustness properties for MPEG-1 video transmitted on either one- or two-tier transmission media. Receiver error concealment is intended to ameliorate the impact of lost video data by exploiting available redundancy in the decoded picture. The concealment process must be supported by an appropriate transport format which helps to identify the image pixel regions which correspond to lost video data. Once the image region (i.e., macroblocks, slices, etc.) to be concealed are identified, a combination of temporal and spatial replacement techniques may be applied to fill in the lost picture elements. The specific details of the concealment procedure will depend upon the compression algorithm being used, and on the level of algorithmic complexity permissible within the decoder. Simulation results obtained from a detailed end-to-end model that incorporates MPEG compression/decompression and a custom cell-relay (ATM type) transport format are reported briefly.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: This paper presents a system for the restoration of image sequences that are degraded by impulsive noise such as scratches or dropouts. The proposed system uses a multilevel block matching algorithm to estimate the motion between frames and considers the use of an impulsive noise detector to improve the quality of restoration as compared to a global median operation. The detector considers the temporal continuity of motion compensated image information and makes a decision as to whether a suspected discontinuity is due to an impulsive distortion or occlusion in the sequence. When a corrupted portion of the image is detected a motion compensated median filter is used to remove the distortion. The paper introduces an extended multistage filter for image sequence processing. It is found that the use of the detector cannot adversely affect the filtered image when compared to the globally filtered image, and the detail preservation is generally better. The speed of processing is also increased since the number of median filtering operations is considerably reduced.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: In accordance with the present invention, the number of bits used to code a frame of video is controlled by controlling the frame size. In a preprocessing stage (40) of a video coding circuit (10), each frame of video is processed by a low pass anti-aliasing filter (43,44) in the horizontal and vertical directions. The cutoff frequencies in the horizontal and vertical directions are determined by a desired frame reduction factor in the corresponding direction. Then to reduce the sampling rate in each dimension, each frame of video is processed horizontally and vertically by a shift varying filter (45,46). When the sampling rate in both the horizontal and vertical directions is reduced by M/N, the number of code bits decreases linearly with M/N.

Abstract: A method and apparatus for analysing the motion of an object in an motion video in which the frame of a video image (suitably converted to graphics format) is displayed on a video display unit and overlaid by a graphics image including a mouse pointer. The mouse is manipulated by the user to capture the pixel coordinates of the desired object in successive frames of the video thereby providing data which represents the variation in position of the object with time.

Abstract: A film-to-video frame image convertor includes a 3-2 pulldown frame convertor for converting signals representing input film frame images, having a lower associated film frame image rate, to signals representing output video frame images having a higher associated video frame image rate. The output video frame images consist of genuine and simulated video frame images, which correspond to actual input film frame images and multiple input film frame images, respectively, in accordance with a 3-2 film-to-video frame pulldown. Each genuine video frame image consists of two video field images corresponding to two actual film field images from the same film frame image. Each simulated video frame image consists of two video field images corresponding to two actual film field images from different film frame images, with one of the two video field images being a duplicate of a video field image in an adjacent video frame image. Identification signals are selectively inserted into the vertical blanking interval of some of the output video frame images to identify which ones are simulated video frame images containing duplicate video field images. This allows the duplicate video field images to be identified and selectively deleted when the video frame images, having the higher associated video frame image rate, are to be reconverted to film frame images having the lower associated film frame image rate.

Abstract: A method for simultaneously displaying images of different resolutions on a single raster scan video monitor begins with the step of storing lower resolution text and graphics data in a first memory. The data in the first memory is used to generate a first video frame having N1 pixels per line. A first video data stream is generated from the first memory at a first rate corresponding generally to the bandwidth of the video monitor. Higher resolution biological waveform data is stored in a second memory. The data in the second memory represents a second video frame having N2 pixels per line. If desired, the second memory can include data for stationary and scrolling high resolution images. A second video data stream is generated from the second memory at a second rate, which is faster than the first rate. The ratio of the second rate divided by the first rate is approximately equal to N2 divided by N1. The first and second video data streams are combined to produce a single combined video data stream that is displayed on the video monitor.

Abstract: A process is provided for creating a high resolution copy of a target video frame selected from a sequence of video frames, wherein each video frame comprises two interlaced fields. The process comprises the steps of: selecting a single field of the target video frame for resolution enhancement; defining a reference target frame having pixel values assigned from the selected single field; defining an enlarged target frame having pixel locations corresponding to the high resolution copy; assigning pixel values from the selected single field to pixel locations in the enlarged target frame which correspond to pixel locations in the selected single field; assigning estimated pixel values to unassigned pixel locations in the reference target frame; selecting a field from one of the video frames in the sequence of video frames which was not chosen as the selected single field as a first object field; estimating motion vectors extending from the reference target frame to pixels in the first object field; identifying accurate motion vectors; assigning the value of a respective pixel for each motion vector identified as accurate to an enlarged target frame pixel location corresponding to an origination point of the motion vector unless the enlarged target frame pixel location was previously assigned a pixel value; and printing the enlarged target frame. Further provided is printing apparatus for creating a high resolution copy of lower resolution video information.

Abstract: The authors use a motion adaptive variable-bit-rate (VBR) video codec and propose a motion classified model to represent the characteristics of various classes of motion activities. The codec switches between interframe, motion compensated, and intraframe coding corresponding to low, medium, and high motions and scene changes, respectively. The model captures the motion of various video scenes and the codec structure by providing the statistics of VBR-coded video' traffic through a first-order composite autoregressive process with three motion classes. The parameters of this model are derived from a VBR-coded sample video sequence such that the bit rate distribution and the autocorrelation in bit rates of two successive frames are matched. The validity and accuracy of the model are verified. Using this model, the characteristics of aggregated traffic sources are discussed. >

Abstract: Motion pictures have a temporal rate of 24 frames per second, while most of the conventional video displays and recording devices utilize a rate of 60 fields per second. In the case of high-definition television (HDTV) systems, some proposals in the US require a video rate of 60 frames per second. Upconversion of motion picture film to 60 frames per second is important since motion picture constitutes a high-quality source material for HDTV. The authors address the problem of motion-compensated upconversion of 24 frames/s digitized motion pictures to 60 frames/s digital video signals. >

Abstract: A system for improving motion-sensitive processing in a television receiver generates motion vectors for video images in a studio environment, encodes the motion vectors and then combines the encoded motion vectors with the video signal for transmission. A receiver decodes the motion vectors and applies them to the motion-sensitive processing apparatus to improve its performance. The motion vector information is encoded during the active portion of the video signal in a manner that does not produce significant distortion when the video signal is processed for display. According to one embodiment of the invention, the motion vectors are encoded in a band of frequencies surrounding the color subcarrier signal as a 16 quadrature amplitude modulated (QAM) signal using Fukinuki-type modulation. According to another embodiment of the invention the motion vectors are encoded using conventional 16 QAM modulation and then used to modulate a carrier signal which is quadrature phase related to the picture carrier signal.

Abstract: Pel-recursive motion estimation algorithms are an attractive alternative to block-matching motion compensation algorithms for video coding because (a) they do not require that motion information by transmitted over the channel, and (b) they allow the reconstruction of continuously varying motion fields. Unfortunately, the high computational complexity of these algorithms and their difficulty in tracking varying motion fields, discontinuities in motion fields, and noisy image sequences have led most current video coding algorithms to use block- based rather than pel-recursive approaches to motion estimation and compensation. This paper presents a new, discrete formulation of pel-recursive motion estimates which allows more flexibility in trading off computational complexity for prediction accuracy, and which permits the design of hybrid motion-estimation algorithms sharing characteristics of both pel-recursive approaches and block-matching approaches. Using the discrete formulation, we defined three novel approaches to motion estimation, one in the form of a conventional pel-recursive algorithm and two incorporating various amounts of block-based motion information from the encoder. We present simulations comparing their performance with both standard pel- recursive and block-matching motion estimation algorithms, demonstrating significant improvements in prediction accuracy.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: An input digital video signal representing a series of input frames is processed to produce an output digital video signal representing a series of output frames with an increased motion blur effect. For each output frame at least one intermediate field or frame is produced by motion compensated temporal interpolation between a pair of the input frames. Each output frame is then produced by combining the intermediate field or frame with at least one further intermediate field or frame and/or with one of the respective input frames so that the output frame has an increased motion blur characteristic compared with that of the input frames. Using motion compensated temporal interpolation, a change in frame rate can also be produced as between the input frames and the output frames.