Abstract: A prefilter for use in a compressive coding apparatus, the compressive coding apparatus including the prefilter for limiting a frequency band of an input image and a compressive coding unit for implementing compressive coding of an image signal of which frequency band is limited with the prefilter, the prefilter includes: a time filter unit; a two-dimensional filter unit; and an enhancement unit. A compressive coding pre-processing apparatus provided with the prefilter includes: a prefilter unit for attenuating a diagonal frequency component of each image; a pixel skipping unit for skipping a pixel of an image signal of which diagonal frequency component is attenuated by the prefilter unit by folding back a horizontal high frequency component to a vertical high frequency component, or folding back the vertical high frequency component to the horizontal high frequency component; and a pixel space contracting unit for contracting a space of the skipped pixel.

Abstract: In the case where a wide-band color picture signal provided for a high-definition television broadcasting is sub-sampled for narrow-band transmission, in comparison with a stationary picture signal which is applied with sub-sampling according to a sampling pattern circulated at every two frames, the color picture signal in motional picture regions, which is conventionally applied with line-offset sub-sampling at every field, has a lowered resolution. To improve the resolution concerned, color difference signals in motional picture regions are applied with inter-field offset sub-sampling together with band-limitation for preventing aliasing distortion accompanied with subsampling and signal processing including interpolation for reproduction, which are effected in a form completed at every frame. As for motional picture regions having small motion, a luminance signal is applied also with similar sub-sampling and similar signal processing.

Abstract: High resolution vertical and horizontal components of a high definition video signal are combined with a standard broadcast system video signal, such as the NTSC system, in which high frequency horizontal resolution components are sampled and used to modulate at least a first sub-carrier signal. The first sub-carrier is frequency interleaved onto the standard broadcast signal. Vertical high resolution components are time compressed and time division multiplexed onto top and bottom portions of the standard broadcast signal. The modified broadcast signal can be decoded by a standard receiver to display a standard resolution video image, while receivers designed to decode the modified signal can time division demultiplex the vertical high resolution components and demodulate the horizontal high resolution components, combine these components with the standard components, and generate a high definition video image.

Abstract: A multiple sub-sampling encoding/decoding system performing interfield and interframe offset sub-sampling of a broad bandwidth television signal. The system compresses the television signal to fit, for example, to the transmission bandwidth of the standard television systems, compensates the transmission characteristics, and achieves the optimal frequency allocation of the modulated transmission signal.

Abstract: A television receiver is provided with two field memories for storing movement control signals, an OR circuit, a frame memory for storing the present and previous fields, a pair of switches controlled by a freeze signal, a switch controlled by the output signal of the OR circuit, and another switch for changing over its output signal to and from the output signal from the switch controlled by the OR circuit and the signal from the frame memory representing the present field. One frame's worth of video signals of the present field and the previous field are stored in the frame memory by a freeze signal. The signals stored in the frame memory provide a freeze picture having no multi-line dimness by virtue of using the present field and the previous field for the still picture image portion and the present field for the moving picture image portions of the present field and the previous field.

Abstract: The motion detection circuit is so constructed that an interframe difference signal is passed through a horizontal direction LPF and a vertical direction LPF in cascade connection, and the interframe difference signal thus obtained is divided by the value obtained by mixing an edge signal of an image and the image level signal of the image by a mixing circuit, thus providing a motion signal.

Abstract: A method and apparatus for detecting the motion of image in a television signal is intended for a decoder of a multiple subsampling transmission signal without an interframe aliased portion in a lower frequency region. In the method and apparatus for detecting the motion, a next-adjacent interframe difference signal, an immediate-adjacent interframe difference narrow-band signal and an immediate-adjacent interframe difference broad-band signal or compensated versions of these signals are combined with maximum-value selection circuits and a minimum-value selection circuit for selecting the maximum-value and minimum-value among these three sets of signals so that a proper motion signal is extracted from the transmission signal.