Nec Corporation

Nec Home Electronics, Inc.

Fujitsu Corporation

Nippon Telegraph and Telephone Corporation

Kokusai Denshin Denwa Co., Ltd.

Pioneer Corporation

Mutsumi Ohta

Ryoma Oami

Toshio Koga

Junichi Ohki

Yoshihiro Miyamoto

Hideto Kunihiro

Yoichi Kato

Kiichi Matsuda

Masahide Kaneko

Atsushi Koike

Yoshinori Hatori

Naoki Mukawa

Hideto Kunhiro

Yasuhiro Kosugi

An error diffusion processing circuit includes an error diffusion processing unit and a noise signal unit. The error diffusion processing unit generates a first output image signal of a first pixel by carrying out an error diffusion process, based on an inputted first input image signal of the first pixel. The number of gray tones of the first output image signal is smaller than that of the input image signal. The noise signal unit which generates a noise signal and outputs the noise signal to the error diffusion processing unit. The noise signal is inputted into a feedback loop of the error diffusion process.

Error diffusion processing circuit for an image signal which improves an output image

A broadcast verification system is provided which enables broadcast verification to be performed by a third party being independent of a broadcasting station, without being assisted by another, at low costs and to be reported to a client. The client submits CM (Commercial Message) images to the broadcasting station and registers feature descriptors in a database. When the broadcasting station broadcasts the CM images in accordance with a contract, a receiving device in a checking base extracts contents from received broadcasting waves and a checking section compares feature descriptors of the contents with that of contents stored in the database. When there is coincidence between them, the checking section transmits comparison results to an aggregating section which creates a report including broadcast time, broadcasting channel, broadcasting state and submits it to the client. A broadcast verifying agent receives a broadcast verification entrusting fee.

Broadcast verification system, broadcast verification method, broadcast verification apparatus and storage medium storing broadcast verification program

The present invention relates to a digital watermark insertion system that automatically calculates a digital watermark strength suitable to an input image and inserts a digital watermark into the image. The image categorizing section classifies input images and outputs category indexes. The storage device stores digital watermark characteristic tables describing the correspondences between digital watermark strength, image-quality degradation degree and attack-resistant evaluation value by category index and selects a digital watermark characteristic table to be used according to an input category index. The digital watermark strength calculation section outputs a digital watermark strength to the storage device, calculates an optimum digital watermark strength using an image-quality degradation degree and a resistant evaluation value output from the storage device and constraint information input by an user. The digital watermark insertion section converts embedded data into a digital watermark and inserts the digital watermark in an input image with the strength of an input optimum digital watermark strength, thus outputting a watermarked image.

Digital watermark insertion system and digital watermark characteristic table creating device

The invention provides a reversible eight-element discrete cosine transform system which can be realized with a practical circuit and provide transform values proximate to those obtained by actual eight-element discrete cosine transform. In 4&times;4 matrix transform which appears when eight-element discrete cosine transform is decomposed in accordance with a high speed calculation method, transform values (X,, X,, X,, X,) are divided into (X,, X,) and (X,, X,), and if (X,, X,) are determined, then possible values as (X,, X,),are limited. This is utilized for quantization of the elements. (X,, X,) are quantized with step sizes of k,and k,by operators to obtain quantization values (Q,, Q,). Meanwhile, from (X,, X,), global quantization values are obtained by a quantizer using a conventional reversible quantization technique while local quantization values are obtained using a second numerical value table, and quantization values (Q,, Q,) are obtained from the values of the gloval quantization values and the local quantization values. Then, an eight-element discrete cosine transform system is constructed by a combination of reversible transform quantization of a 4&times;4 matrix and conventional reversible transform quantization of a 2&times;2 matrix.

Lossless transform coding system for digital signals

The invention provides a coding system and a decoding system wherein a discrete cosine transform which provides a high coding efficiency is approximated to allow reversible coding and decoding while maintaining the high coding efficiency and a system which includes such coding and decoding systems. Reversible coding is realized by multiplying a transform matrix by a fixed number for each row to approximate the transform matrix with integer values, performing re-quantization in a basic region defined by a multiple of a determinant for suppressing redundancy while maintaining a condition wherein reversible coding is possible in the basic region, and performing re-quantization for the entire region making use of the fact that such basic region appears periodically in a signal space.

The invention provides a reversible eight-element discrete cosine transform system which can be realized with a practical circuit and provide transform values proximate to those obtained by actual eight-element discrete cosine transform. In 4.times.4 matrix transform which appears when eight-element discrete cosine transform is decomposed in accordance with a high speed calculation method, transform values (X.sub.1, X.sub.7, X.sub.3, X.sub.5) are divided into (X.sub.1, X.sub.7) and (X.sub.3, X.sub.5), and if (X.sub.1, X.sub.7) are determined, then possible values as (X.sub.3, X.sub.5), are limited. This is utilized for quantization of the elements. (X.sub.1, X.sub.7) are quantized with step sizes of k.sub.1 and k.sub.2 by operators to obtain quantization values (Q.sub.1,) Q.sub.7). Meanwhile, from (X.sub.3, X.sub.5), global quantization values are obtained by a quantizer using a conventional reversible quantization technique while local quantization values are obtained using a second numerical value table, and quantization values (Q.sub.3, Q.sub.5) are obtained from the values of the gloval quantization values and the local quantization values. Then, an eight-element discrete cosine transform system is constructed by a combination of reversible transform quantization of a 4.times.4 matrix and conventional reversible transform quantization of a 2.times.2 matrix.

For digital signals provided with motion vectors of a plurality of regions, a conversion coefficient for a respective one of the motion vectors is determined in accordance with the respective motion vector and a shape of a corresponding one of the regions on which the respective motion vector represents a motion, linear conversions of the digital signals are performed by using the respective coefficients of the motion vectors, and an accumulation is made of results of the conversions for the respective motion vector by the linear conversion step so that the linear conversions are overlapped with each other.

System and method for motion compensation on sub-band represented

The invention provides a coding system and a decoding system wherein a discrete cosine transform which provides a high coding efficiency is approximated to allow reversible coding and decoding while maintaining the high coding efficiency and a system which includes such coding and decoding systems. Reversible coding is realized by multiplying a transform matrix by a fixed number for each row to approximate the transform matrix with integer values, performing requantization in a basic region defined by a multiple of a determinant for suppressing redundancy while maintaining a condition wherein reversible coding is possible in the basic region, and performing requantization for the entire region making use of the fact that such basic region appears periodically in a signal space.

A motion compensation circuit comprises finite impulse response (FIR) filters divided into N groups according to N subbands of input video signal samples. One of the FIR filters of each group receives a delayed version of the subband of the group, and the remainder of the group receives a delayed version of one or more of the subbands which are adjacent to the subband of the group. Each FIR filter has tap-weight multipliers controlled in response to an estimated motion vector for shifting sample points of each subband. N adders are provided corresponding respectively to the N groups of FIR filters for summing the outputs of the FIR filters of the corresponding groups to produce N motion compensation signals.

Motion compensation circuit

In a subband coding device for coding a digital device input signal which is a one-dimensional or a two-dimensional signal, a single coding circuit is used instead of a conventional combination of coders and a multiplexer. The coding circuit is for coding subband samples of different frequency bands in each sample group across the frequency bands, as by starting from a lowest frequency band and ending at a highest frequency band or reversedly, and preferably with attention directed to correlation which the subband samples have between two adjacent frequency bands. Zero-level components of the subband samples are preferably run-length coded. When the subband samples of each sample group have a tree structure including subtrees, the subband samples are preferably scanned from a subtree to another subtree either starting at or ending at the subband sample of the lowest frequency band.

Device for subband coding with samples scanned across frequency bands

In a predictive coding device responding to a sequence of image data signals representative of picture elements to produce a sequence of coded output signals, a plurality of provisional error signals are calculated for each picture element from the image data signals and different provisional prediction signals sent from predictors and are given weights in multipliers from a weight decision circuit in consideration of a position of each picture element to produce weighted error signals. The weighted error signals are summed up into a first sum signal by a first adder circuit and thereafter processed into the coded output signals and local decoded signals which are sent to the predictors. The predictors may carry out either different prediction from one another for each picture element or identical prediction in relation to different blocks. Alternatively, a motion vector which is calculated for each block may be smoothed in consideration of the other motion vectors calculated for adjacent blocks on motion-compensated prediction. Thus, weighted means values are calculated as the weighted error signals and/or smoothed motion vector at every picture element so as to mitigate a discontinuity among the blocks.

Predictive coding device capable of coding image data signals without a

In a decoding device for decoding an input signal into a decoded signal, a delay circuit delays the decoded signal into a delayed signal with a delay equal to a frame period of a digital video signal which is encoded into an encoded signal by interframe predictive encoding. A forward filter of a predetermined filtering characteristic filters the delayed signal into a first filtered signal. An adder adds the input signal to the first filtered signal to produce an added signal. A subtracter subtracts the input signal from the delayed signal to produce a subtracted signal. An inverse filter filters the subtracted signal into a second filtered signal. Responsive to a mode signal, a selector selects one of the added and the second filtered signals to produce, as the decoded signal, the added and the second filtered signals when the mode signal indicates that the input signal is produced in a forward direction from a leading part to a trailing part of the encoded signal and when the mode signal indicates that the input signal is produced in a backward direction reversed relative to the forward direction, respectively. Another inverse filter may be inserted between the delaying circuit and the subtracter. In this case, the subtracter and the second filter are replaced in position with each other.

Decoding device capable of forwardly and backwardly reproducing pictures

In a reproduction system for use in reproducing a still image from a sequence of predictive error signals which is read out of a memory and which is preliminarily processed into a sequence of preliminary processed signals, an intermediate circuit interrupts the preliminary processed signals in response to an external command signal. In the intermediate circuit, the external command signal is resampled by a sequence of frame pulses in a resampling circuit into a resampled signal so as to close a gate circuit. No predictive error signal is sent to an adder circuit during absence of the gate circuit. An identical error signal is repeatedly produced as a sequence of reproduced signals to reproduce the still image.

Reproduction system capable of reproducing a still image by interrupting

In an image processing system for use in processing a sequence of image signals carrying a moving image, the image signal sequence is divided into a sequence of partial image signals each of which carries a scene subsequence defined by scene changes. A background signal generator determines a background portion of the moving image by monitoring a whole of each partial image signal and produces a background signal. The background signal is coded by a coder prior to a sequence of error signals resulting from predictive coding of each partial signal. During prediction of the background signal, the error signals may be rendered to zero in the coder. The background signal may be either determined at every picture element or at every block composed of a plurality of picture elements.

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Tokyo, Japan

Mutsumi Ohta