Kokusai Denshin Denwa Co., Ltd.

Kokusai Denshin Denwa Kabushiki Kaisha

Satoshi Miyaji

Shuichi Matsumoto

Takahiro Hamada

A motion detecting device for enhancement of the image quality at ultra-low bit rates is disclosed, which permits quantization of the prediction error with the highest possible degree of accuracy, taking into account the amount of information which is generated by a motion vector generated by a motion vector generator. A difference vector corresponding to a difference between the motion vector and a motion vector of an already encoded reference pixel block located near the current pixel block to be encoded in said current frame is obtained. An output resulting from a motion detection of the difference vector so as to obtain the minimum step size from said difference vector, through the use of the number of generated bits and the number of bits of said difference vector, is encoded.

Motion compensation image encoding device

This invention aims to provide a method and apparatus for detecting a synchronization shift in which the synchronization shift between an original image and a reproduced image can be accurately detected even if noises are generated by a video codec or the like. An original image sent out from an image source has a sine wave for synchronization overwritten thereon in a frame memory. The image on which the sine wave has been overwritten is decoded in a codec and stored in another frame memory. The two images srored. in two frame memories are simultaneously started to be read out. From the image from the other frame memory, only the sine wave is extracted in a notch filter, subjected to an offset correction in an adder, and inputted to asynchronization shift detecting unit. The synchronization shift detecting unit uses the sine wave to detect line, frame and horizontal pixel shifts. Since a sine wave is used as a synchronization marker and only the sine wave is extracted in the notch filter, the synchronization shift can be accurately detected.

Method and apparatus for detecting synchronization shift between original image and reproduced image of video signal

An apparatus for evaluating digital picture quality, includes a SNR calculation module for calculating a SNR based upon differences between data of video picture to be evaluated and data of original video picture, a module for calculating a power of AC component of overall data of one of the video pictures in a frame, and a weighting module for weighting the calculated SNR based upon the calculated power of the AC component.

Apparatus for evaluating digital picture quality

When a selective decision of the field mode/frame mode for orthogonal transform is made for each macroblock composed of a plurality of blocks in a motion picture coding system wherein coding of an interlaced TV signal proceeds in the frame structure and an orthogonal transform is made in the unit of a block, the respective variances of the blocks within the macroblock are calculated, the calculated results are substituted respectively into an monotonously increasing and saturation tending nonlinear function to evaluate the sum of these functional values, and such a decision is made as to select the smaller mode in sum.

Method and apparatus for deciding optimum orthogonal transform mode

A method for coding moving pictures using motion compensation for prediction has a step of producing motion vectors for a macroblock in a previous frame, the macroblock corresponding to a macroblock to be coded in a current frame, a step of motion-compensating the macroblock in the previous frame by using the produced motion vector to generate a motion compensated macroblock, a step of calculating a prediction error from the motion compensated macroblock and the macroblock to be coded in the current frame, a step of deciding whether the macroblock to be coded in the current frame is a significant macroblock or a non-significant macroblock by comparing the calculated prediction error with a threshold value, a step of coding the macroblock to be coded in the current frame when the macroblock is decided as the significant macroblock, and a step of transmitting only the produced motion vector when the macroblock is decided as the non-significant macroblock. Particularly, the produced and transmitted motion vector is selected to one with the minimum length within a range in which the macroblock to be coded is decided as the non-significant macroblock.

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Tokyo, Japan

Satoshi Miyaji