Mitsubishi Denki Kabushiki Kaisha

Luma Telecom Incorporated

Takayoshi Semasa

Fumitaka Ono

Yutaka Ueno

Tomohiro Kimura

Makoto Matsumoto

Toshimasa Tomoda

Haruhiko Nagai

Shuji Iwata

Lawrence D Emmons

Yasuhito Myoi

Fumio Suzuki

Hiroshi Mitsuda

Yoshisuke Ohtsuru

Koji Kaneko

Toshio Itoh

Kenji Tatsumi

Yukiyasu Kawahata

Shuzi Iwata

Tsunehiro Imamura

Syuzi Iwata

Ryoichi Ohnishi

A coding apparatus includes: a context generator generating a context signal from a reconstructed symbol; a predictor generating a prediction signal indicating a prediction value which is a prediction of a symbol to be coded, based on the context signal, and a prediction error signal which is a difference between the prediction value and the symbol; a quantizer generating a quantized prediction error signal by quantizing the prediction error signal; an encoder coding the quantized prediction error signal by referring to the context signal; an inverse quantizer subjecting the quantized prediction error signal to inverse quantization so as to generate a reconstructed prediction error signal; an inverse predictor subjecting the reconstructed prediction error signal to inverse prediction so as to generate a reconstructed sampled signal; a subsampling control circuit generating a subsampling control signal indicating whether or not the symbol should be subject to subsampling; and an interpolator referring to the subsampling control signal so as to subject to interpolation the reconstructed sampled signal corresponding to the symbol subject to subsampling, wherein the coding apparatus codes symbols while adaptively employing subsampling.

Coding method, coding apparatus, decoding method and decoding apparatus using subsampling

A plurality of liquid crystal modules is vertically and horizontally arranged, each of which is supplied light by a light source via optical fibers. A screen can be wound up at a cabinet. An image from each of the plurality of liquid crystal modules does not interfere one another because a light shielding board is installed.

Image display system

An image processing device for effecting resolution conversion includes an image signal memory (1) for storing the input pixel levels I.sub.xy, and an enlargement/reduction calculator circuit (2) for calculating a grey level G.sub.XY of each output pixel corresponding to the average of the areas of input pixel intersecting with the output pixel. The error occurring upon quantization by a quantizer (4) is calculated by an error calculator (5), and, after being delayed by one pixel by an error memory (6), is fed back to a image signal compensator circuit (3) to be added to the grey level S3 to obtain the compensated gray level S4, which is quantized by the quantizer (4) to obtain the quantized level O.sub.XY.

Image processing device for resolution conversion

An image processing apparatus for outputting an image which contains different kinds of multi-level signals for letters, figures, photographs, screened-halftone, etc. The apparatus comprises a screened-halftone pattern detecting circuit and a continuous-tone pattern detecting circuit for detecting a screened-halftone pattern and a continuous-tone pattern, respectively, by using neighboring pixels of the target pixel, counters for counting UP/DOWN in accordance with the outputs of the detecting circuits, a filter for switching the filtering coefficients of the image signal in multiple stages in accordance with the outputs of the counters and a quantizer for bi-level-quantizing the output of the filter. It is thus possible to produce an image having a good quality free from deterioration due to the rapid switching of region judgements and bi-level-quantizing methods.

Image processing apparatus and method for multi-level image signal

Encoding and decoding devices which are capable of increasing the encoding and decoding speed. In arithmetic encoding, there is a possibility of encoding with high efficiency which is very close to the entropy of the information source, but the encoding and decoding time is generally longer than that in another encoding systems such as an MMR encoding system. For example, in a standard facsimile equipment, about 1.3 sec is required for encoding the picture information in an A4-size copy. In prediction encoding, a memory for storing the past reference symbols and the predicted values therefor is necessary for prediction. Since the memory capacity is generally large, a large-capacity RAM is used. The encoding time is therefore greatly dependent on the access speed of the RAM. In the present invention, a high-speed register for storing the predicted value for a special symbol pattern is provided separately from the RAM so that the predicted value of the special symbol pattern is read from this register, thereby enabling high-speed encoding.

Encoding and decoding devices with predictor and detector

A still-picture TV telephone system for transmitting and receiving, via a telephone circuit, a still picture taken by a camera; a picture signal stored in a memory is modulated in phase and amplitude digitally and is offered or supplied to the telephone circuit during talking in voice. To superposing the talk in voice also during offering of the picture signal, the voice and picture signals are divided by frequency band. The frequency band of the voice signal is partially restricted, and the picture signal is inserted in the omitted band, during which time the picture signal is restricted in band by setting the band rate frequency to be lower than the carrier signal frequency when modulating the phase and amplitude. The picture signal is further restricted in band by a low-pass filter so that the voice and picture signals are separated by band so as not to overlap each other at the same frequency band.

Transmission system for still-picture TV telephone

An input gray-scale image is converted to a bilevel output signal by an image-processing apparatus with two binarizing circuits: one employing a uniform threshold and the other a dither matrix. The outputs of these circuits are selected for each pixel by deciding whether the pixel is a bilevel pixel or a gray-scale pixel. The decision is based on the maximum and minimum gray levels in a block of pixels centered on the pixel in question. Images having both bilevel and gray-scale parts can thus be binarized with clean reproduction of black-white edges.

Image-processing apparatus

The present invention provides a QAM modulation scheme compatible with a single channel demodulator. The inphase (I) channel is provided with luminance information encoded on a series of sine wave symbols. The quadrature (Q) channel is used for color difference values with a sine or cosine symbol being used for each color difference value. Alternate ones of these color difference symbols are inverted so that, on the average, their effect on the I channel zero-crossings simply cancels out. Thus, when sent to a single channel demodulator which expects a black and white picture, the quadrature channel will be filtered out; leaving luminance information which will be decoded as a black and white picture. The color information does not disturb the zero crossings of the luminance signal on an averaged basis, allowing the carrier recovery phase lock loop to maintain synchronization for demodulation purposes. When received by a QAM demodulator, the color difference values are recovered on the Q channel, to give a color picture. In one embodiment, the cosine symbols on the channel are offset with a positive or negative DC value, depending on whether the symbol is inverted, to shift the Q channel zero-crossings so they are aligned with the I channel zero-crossings.

Quadrature amplitude modulation preserving one channel zero crossing for

Binary signals from picture elements arranged in rows and columns of the subject copy are successively applied to a group of shift registers and suitably time-delayed under the control of clock pulses so that the signals from reference picture elements for each object picture element simultaneously enter two logic circuits provided for a high and low scanning resolution. The logic circuits calculate predicted values for each object element following respective prediction functions. That circuit for the scanning resolution used delivers the predicted value to an exclusive OR gate also supplied with the actual signal from the same object element. Each time the gate determines a discord with the prediction, a coder delivers coded serial signals having predetermined variable lengths dependent upon the number of pulses counted up to that time by the coder. Also by referring to a picture element or elements farther distant from the object element, generized prediction functions are disclosed.

Facsimile communication system

Binary 0's and 1's from picture elements in each line are counted with respect to each mode determined by adjacent picture elements to form symbol patterns determined by both the counts and the information content of a memory. Each pattern is encoded into a code word to be transmitted having a bit number determined by the arrangement of binary symbols included in it. Also the code words can be transmitted on the basis of address numbers of picture elements, starting with the output from a coder associated with a mode having the two-valued signal with the least address number.

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Kamakura, Japan

Takayoshi Semasa