摘要:
A videophone takes a live picture of the user, sends the live picture during part of a call, generates a processed picture different from the live picture, and sends the processed picture during another part of the call. The processed picture may be prepared in advance, or may be generated by combining the live picture with a prepared picture. Alternatively, the processed picture may be obtained by increasing a quantization coefficient of the live picture, producing a mosaic effect that disguises the live picture. The processed picture can be sent to protect the privacy of the videophone user, or to provide appropriate transition at the beginning or end of the call. The processed picture can also be sent when the call is placed on hold.
摘要:
By changing coefficients of second-order and first-order calculation terms relating to respective hues, and first-order calculation terms in the form of comparison-result data relating to respective inter-hue areas, only the target hue or inter-hue area among the six hues of red, blue, green, yellow, cyan, and magenta, and the six inter-hue areas can be varied, without affecting other hues and inter-hue areas. Thus, the six hues and six inter-hue areas can be corrected independently, and the large-capacity memory is not required.
摘要:
The present invention relates to a motion vector detection method and system for detecting a motion vector for motion compensation in moving picture compression. The motion vector detection system reduces the amount of operations without degrading the quality of an image. A vector memory stores a motion vector having been obtained. A predicted motion vector calculator predicts the motion vector of a block to be predicted based upon the motion vector of a block adjacent to the block to be predicted. The search range determiner determines a search range based upon the motion vector predicted. The motion vector detector performs block matching within the search range.
摘要:
A high-efficient coding apparatus and method for compressing a digital video signal such as a color television signal, by dividing the digital video signal into a plurality of sub-bands, formatting the video signal of each sub-band into blocks per every plurality of picture elements, performing an orthogonal transform to each formatted block and coding coefficients obtained by the orthogonal transform.
摘要:
A coding apparatus reduces a digital image signal. The coding apparatus includes a block formatting circuit for dividing the digital image signal into blocks of a plurality of picture elements, an orthogonal transforming circuit for transforming the blocks of plurality of picture elements into a plurality of coefficients, an adaptive quantizing unit for quantizing the plurality of coefficients with a quantization table, a calculating circuit that divides each block of the digital image signal into a plurality of sub-blocks and obtains a plurality of indexes, and a detecting circuit that obtains a maximum index and a minimum index from the plurality of indexes. Each index indicates a degree of change between the picture elements in a sub-block of the plurality of sub-blocks. The coding apparatus further includes a subtracting unit that obtains a difference between the maximum index and the minimum index, and a selecting unit that obtains the quantization table from a plurality of quantization tables according to the minimum index and the difference. As a result, the image quality of the background having little change in the signal is kept good.
摘要:
A frequency demodulator includes an analog-to-digital converter for converting an inputted FM signal into a digital signal. A 90.degree. phase shifter is used to phase shift the converted digital signal. The phase shifted signal and the converted signal are utilized to determine the results of tan.sup.-1 (X/Y). X represents the converted signal, and Y represents the phase shifted signal. The result from the calculation is delayed for a period of time equal to one sampling cycle. The frequency demodulator also includes a subtractor for subtracting the delayed signal from the calculation result. A discontinuity corrector corrects any discontinuity in an output from the subtractor, and a reversal phenomenon compensator compensates the output from the discontinuity corrector when the output from the discontinuity corrector exceeds a predetermined range of levels. These levels correspond to an appearance of discrete lines of black or white color on a reproduced picture.
摘要:
An encoding controller (106) generates and outputs a current skip signal (SKi) to a switch circuit (108), and outputs a quantization parameter (Qp) for controlling a code amount after the encoding processing of a current VOP by an encoder (103) using a current scene change signal (SCi), to an encoder (106). The current scene change signal (SCi) is set on the basis of the current VOP, a previous scene change signal (SCi-1), and a previous skip signal (SKi-1).
摘要:
An encoding system capable of preventing the overflow of a buffer and performing the encoding of a VOP within a predetermined time period even where the processing time period necessary for encoding each macroblock is not constant. In order to provide the encoding system, the maximum number of bits Tmax is set for each VOP, and the output of encoding unit and the output of fixed code output unit is switched and outputted so that the number of bits Sc of the VOP may not exceed the Tmax.
摘要:
An image encoding device is provided that can transmit encoded image data without lowering the frame rate even when the transmission speed of the transmission path is lowered. An encoded region designator selects the region that is to be encoded, in the input image, depending on the bit rate of the transmission path. Only such a region that is designated by the encoded region designator is encoded. The encoded region designator may be one which selects the region that is to be encoded, according to the bit rate of the transmission path, and the motion vector detected by the image encoding circuit. As an alternative, an encoded region designator may be used which selects the region that is to be encoded according to the bit rate of the transmission path, and the information on the designated region supplied from the outside. Also, a selector limiting the number of bits of the signal from the image signal input circuit may be provided, and when the bit rate of the transmission path is lowered, the number of bits of the input image may be adaptively switched.
摘要:
In an image signal encoding method for encoding an image signal using motion compensation, a motion vector is found by means of a block matching method, a first distortion SEmc of motion compensated prediction associated with the motion vector, and a second distortion SEnomc of prediction without motion compensation are detected, the motion vector is used for for inter-picture prediction encoding when SEnomc>SEmc+K, with K being a constant greater than 0, and a vector having a value zero is used, in place of the motion vector, for inter-picture prediction encoding when SEnomc≦SEmc+K. In another aspect, a speed of motion in a sequence of pictures is detected, and for a part of the sequence of pictures detected to contain a quick motion, the prediction encoding is performed using one-way prediction encoding, and for a part of the sequence of pictures without a quick motion, prediction encoding is performed using bi-directional prediction encoding. In another aspect, the image signal is subsampled for each field, and a motion vector is determined using the field-subsampled image signal.