Abstract: In order to reduce the power consumed by the circuit when the image data is transferred to a memory in a display means, a write region detecting means 8 is provided to detect the address region in the graphics memory 2 accessed for writing by the image data writing means 1, and only such data that is within the region including the addresses accessed by the writing means 1 is transferred to the memory 5 in the display means 4. The region including the accessed addresses may for example a rectangular region of from the minimum vertical direction address to the maximum vertical direction address Y among the accessed addresses, and from the minimum horizontal direction address to the maximum horizontal direction address among the accessed addresses.

Abstract: 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.

Abstract: In order to reduce the power consumed by the circuit when the image data is transferred to a memory in a display means, a write region detecting means 8 is provided to detect the address region in the graphics memory 2 accessed for writing by the image data writing means 1, and only such data that is within the region including the addresses accessed by the writing means 1 is transferred to the memory 5 in the display means 4. The region including the accessed addresses may for example a rectangular region of from the minimum vertical direction address to the maximum vertical direction address Y among the accessed addresses, and from the minimum horizontal direction address to the maximum horizontal direction address among the accessed addresses.

Abstract: 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.

Abstract: A video contrast enhancer enhances luminance contrast by dividing each video frame or field into blocks, calculating a mean luminance level for each block, selecting mapping functions on the basis of these mean luminance levels over a series of frames or fields, and mapping the video luminance levels according to the selected mapping functions. Color-saturation contrast is enhanced by modifying the amplitude of the modulated chrominance signal by the histogram equalization method, preferably by making a single linear modification in each period of the chrominance signal, so that color phase is not affected. For video signals with non-picture bands, these enhancements are preferably restricted to the picture area. If a black offset is present, it is preferably removed.

Abstract: A luminance (Y) and chrominance (C) signals separating filter includes a motion detecting circuit which partially detects a movement of an image utilizing a correlation between frames; an inter-frame YC separating circuit which performs a separation utilizing the inter-frame correlation when the motion detecting circuit detects a still image, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; an intra-frame YC separating circuit which partially detects a correlation between fields or between frames and a correlation in a field when the motion detecting circuit detects a moving image, performs a separation utilizing the correlations, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; a C signal mixing circuit which mixes the inter-frame YC separated C signals and the intra-frame YC separated C signals in accordance with an output of the motion detecting circuit and outputs motion adaptive YC separated C signals; and a Y signal mixing circu

Abstract: A filter is used for separating luminance and color signals from a composite color television signal in which the frequency of the color signal is multiplexed over the high-frequency region of the luminance signal. When a picture is detected with respect to its motion under frame correlation and if that motion is relatively small, the separation of luminance and color signals is performed based on the interframe correlation. If the motion is relatively large, the separation of luminance and color signals is made based on the interfield correlation. The luminance and color signal separation based on the interfield correlation is attained from a correlation with signals in a field spaced forwardly away from the subject field by one field. This is accomplished by selecting a calculation having the highest correlation in calculations for an objective sample point and a plurality of sample points located about the objective sample point.

Abstract: Motion-adaptive chrominance-luminance separation of a composite video signal is accomplished by comb-filtering the video signal on the time axis, bandpass-filtering the video signal on at least one spatial axis selected according to spatial correlation detected in the video signal, and combining the two filtered results in proportion to motion detected in the video signal. Motion is detected in part by obtaining a one-frame difference signal that has been filtered to eliminate chrominance information; here too the filtering is performed on at least one spatial axis selected according to spatial correlation. Selecting the spatial filtering axes according to spatial correlation enables chrominance and luminance to be separated effectively without unnecessary information loss.

Abstract: A filter for motion adaptive Y/C separation, which is capable of obtaining image of high resolution and little picture quality degradation in the case where an image is switched from static one to motion one or vice-versa, is provided with a filter for extracting Y signal outputting Y signal and a filter for extracting C signal outputting C signal, by detecting whether image is motion one or static one by a motion detecting unit, and when motion image is detected, by detecting partially interframe correlation or correlation in three fields, and according to the detection result, by adaptively switching a plurality of processings for extracting intraframe Y signal and a plurality of processings for extracting intraframe C signal.

Abstract: A filter is used for separating luminance and color signals from a composite color television signal in which the frequency of the color signal is multiplexed over the high-frequency region of the luminance signal. When a picture is detected with respect to its motion under frame correlation, and if that motion is relatively small, the separation of luminance and color signals is performed based on interframe correlation. If the motion is relatively large, the separation of luminance and color signals is made based on interfield correlation. The luminance and color signal separation based on the interfield correlation is attained from a correlation with signals in fields spaced forwardly and rearwardly away from the subject field by one field. This is accomplished by selecting a calculation having the highest among a plurality of calculations for an objective sample point and a plurality of sample points located about the objective sample point.

Abstract: A luminance (Y) and chrominance (C) signals separating filter includes a movement detecting circuit which partially detects a movement of an image utilizing a correlation between frames; an inter-frame YC separating circuit which performs a separation utilizing the inter-frame correlation when the movement detecting circuit detects a still image, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; an intra-frame YC separating circuit which partially detects a correlation between fields or between frames and a correlation in a field when the movement detecting circuit detects a moving image, performs a separation utilizing the correlations, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; a C signal mixing circuit which mixes the inter-frame YC separated C signals and the intra-frame YC separated C signals in accordance with an output of the movement detecting circuit and outputs movement adaptive YC separated C signals; and a Y signal mi