摘要:
An image signal coding device capable of attaining a high-speed coding operation without increasing a circuit scale. The image signal coding device includes a DCT section for performing two-dimensional orthogonal transform to each of plural pixel blocks obtained by dividing an image signal to generate a transform coefficient, a linear quantization section for linearly quantizing the transform coefficient by using given quantization characteristics to generate a quantized coefficient, and a variable length coding section for performing variable length coding to the quantized coefficient to generate code data. The image signal coding device further includes an effective region holding section for holding region information including a range of the transform coefficient to be linearly quantized by the linear quantization section and a range of the quantized coefficient to be coded by the variable length coding section.
摘要:
An image coding device for coding an input image of multi-level. In the image coding device, an input multi-level image is analyzed by an image analyzing portion, and update information to be used when a probability estimation value is generated is generated by an update value determining portion on the basis of adjoining pixel information as a result of the analysis by the image analyzing portion. Further, a probability estimation value is generated by a probability estimating portion on the basis of the update information generated by the update value determining portion and the result of the analysis by the image analyzing portion, and the input multi-level image is arithmetically coded by a code word generating portion on the basis of the probability estimation value generated by the probability estimating portion.
摘要:
An index signal and a delta signal are generated from an input pixel value, and then, inputted to an input buffer by every predetermined pixel to be processed. A controlling unit compares the index signal in the input buffer with a tag (index signal) in a coefficient cache. When they coinside with each other, the controlling unit reads out the corresponding coefficient from the coefficient cache and supplies the same to an interpolating unit. The interpolating unit simultaneously receives the delta signal and supplies the keeping color data to an output buffer. Thereafter, the interpolating unit accesses to the coefficient storing memory by using an index signal that does not coinside with either one of cache-tag (index signal) to obtain a coefficient, and similarly, interpolatively generates color data. Data of converted color is outputted from the output buffer in the order of inputting the pixel. A color converting device of the present invention can perform a color conversion with high precision without increasing a reading-out band of a coefficient table for a color conversion.
摘要:
An image transforming section subjects image data to compression processing. A quantizing section quantizes the transformed data using a quantization width. A variable-length coding section subjects the quantized data to variable-length coding. A code-amount computing section determines a total code amount by accumulating partial code amounts. A control section performs control based on the code amount. An estimating method selecting section adaptively selects a quantization width estimating method. A coded result storage section stores data of a code amount corresponding to the quantization width. First and second quantization width estimating sections have different quantization width estimating methods.
摘要:
An input image is divided into blocks each represented by n.times.n matrix X, and then X.sup.T X is calculated. Singular values of X that are positive square roots of eigenvalues of X.sup.T X and first singular vectors that are normalized eigenvectors of X.sup.T X are calculated by, for instance, the Jacobi method. Second singular vectors that are normalized eigenvectors of XX.sup.T are calculated analytically using the singular values and the first singular vectors. The singular values and the first and second singular vectors thus calculated are coded.
摘要:
An image quality control apparatus having an image divider, a converter, an image analyzer, an image output property circuit, a quantization method selector, a quantizer and a coder. The image divider divides an input image into a plurality of divided images including a predetermined number of picture elements. The converter converts the divided images into converted coefficients. Then, the image analyzer determines a property of the divided images which is output by the image output property output circuit. A quantization selector selects a quantization method in response to the divided image property that was found by the image analyzer and the image output property output circuit. The quantizer quantizes the conversion coefficients found by the converter in accordance with the quantization methods selected by the quantization selector. A coder then codes the conversion coefficients quantized by the quantizer.
摘要:
A plurality of reference pixel extracting means check their corresponding reference pixel ranges and pixel values in predetermined auxiliary regions. Reference pixel range selecting means selects a reference pixel range based on the checked pixel values. When the number of types of pixel values for an input image is found to be locally low in the selected reference pixel range, the number of reference pixels is increased. On the other hand, when the number of types of the pixel values for the input image is found to be locally large, the number of reference pixels is decreased. As a result, states can be generated by a Markov model image encoding system capable of improving encoding efficiency without increasing the number of the states sharply. Owing to the above construction, even when the number of tones for the input image is high upon Markov model image encoding, the number of reference pixels can be increased without abruptly increasing the number of states later on to improve compression efficiency.
摘要:
An image information coding apparatus includes a block generator for dividing image information into pixel blocks, each of which consists of a predetermined number of pixels. A block selector selects a pixel block in a position different from that of a pixel block selected in a preceding block line in a main scanning direction from the pixel blocks generated by the block generator. A parameter setting device sets a coding parameter to a predetermined value. A first variable-length coding device conducts variable-length coding of the pixel block selected by the block selector using the coding parameter. A code amount controller changes a value of the coding parameter so that the code amount of the pixel block selected by the block selector and coded by the first variable-length coding device is not more than a predetermined code amount, and a second variable-length coding device conducts variable-length coding of all of the pixel blocks using a coding parameter changed by the code amount controller.
摘要:
In a coding system, when any of the prediction results of pixel value prediction sections 20 and 21 matches an object pixel, a coding section 50 codes an identifier of the pixel value prediction section whose prediction result matches the object pixel. When none of the results match the object pixel, the coding section 50 codes a prediction error of a prediction error calculation section 30. A decoding system decodes code to an identifier or prediction error and outputs pixel data from the corresponding pixel value prediction section based on the identifier or takes out pixel data from a prediction error addition section 31 based on the predication error.
摘要:
A one-block extracting section extracts a pixel block from an input image signal. An area judging section calculates characteristic quantities such as variance information, histogram information and dynamic range information, and judges whether the pixel block is photographic or text-like based on the characteristic quantities. A photographic pixel block is coded by a transform coding section, and a text-like pixel block is coded by a block truncation coding section.