Abstract: An image processing apparatus for overwriting image data at a low cost and high speed. An image input unit sequentially inputs partial data of an image data. An overwriting unit overwrites a non-coded partial data stored in a compressed page memory with the input partial image data and stores the result in a small area buffer. A process prediction unit analyzes a plurality of image data that are objects of an overwriting process, and predicts whether further overwriting is performed. When it is predicted that no further overwriting is performed, the partial image data is coded in a coder and updated in the compressed page memory. When it is predicted that a further overwriting is performed, the non-coded image data is updated in the compressed page memory. When the overwriting process of every partial image data of all of the image data is complete, the overwritten image data is stored as code data in the compressed page memory.

Abstract: Conversion between different codes can be implemented at high speed by a small device. A code input unit inputs a code. A compatible information reference unit refers to compatible information of each compressed symbol before and after code conversion, which then sends out compatible information data to a compressed symbol conversion unit. The compressed symbol conversion unit converts each of the compressed symbols in the input code data to a form adapted to a code to be converted based on the compatible information data, which then sends out converted code data to a converted code output unit.

Abstract: An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the basis of the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.

Abstract: An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the basis of the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.

Abstract: The present invention presents an image processing apparatus that performs rotation, enlargement, reduction, clipping or overlapping processing of images at high speed using low capacity memories instead of page memories and without the need to read image data in repetition. A first band data storing element receives input image data line by line and stores it as local data. The local data stored in the first band data storing element is transformed by local data transforming element and then stored in a transformed data storing element. The local data is then read in the order it is to be output and stored in a second band data storing element. An image output element then outputs the local data as an output image.

Abstract: An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.

Abstract: 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.

Abstract: The image input from the image inputting portion 10 are DCT-converted by the DCT portion 20, then the converted result is quantized by the quantizing portion 40, then the quantized result is entropy-coded by the entropy coding portion 50, and then the coded output is output. The quantization table calculating portion 30 holds respective reference quantizing steps for the reference resolution, then receives the resolution data of the input image, then calculates respective quantizing steps based on (quantizing step)=(reference quantizing step)/(reference resolution)×(resolution of the input image) so as to fit to the input image, and then prepares the quantization table.

Abstract: An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the basis of the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.

Abstract: An input image is subjected to transform by a DCT transforming unit 20. A coefficient analyzing unit 30 compares a predetermined coefficient and coefficient data 120, and obtains low-frequency image data 150 of the input image by a high-frequency coefficient masking unit 50 and an inverse DCT unit 60 on the basis of a result of that comparison. A pixel subsampling unit 70 receives this low-frequency image data 150, and generates a subsampled image on the basis of the aforementioned result of comparison. The subsampled image and coefficient information are transmitted to a decoding side. A decoding apparatus decodes an image on the basis of the subsampled image and the coefficient information.

Abstract: The present invention presents an image processing apparatus that performs rotation, enlargement, reduction, clipping or overlapping processing of images at high speed using low capacity memories instead of page memories and without the need to read image data in repetition. A first band data storing element receives input image data line by line and stores it as local data. The local data stored in the first band data storing element is transformed by local data transforming element and then stored in a transformed data storing element. The local data is then read in the order it is to be output and stored in a second band data storing element. An image output element then outputs the local data as an output image.

Abstract: A system and method are provided for realizing high speed and high efficiency in compression of image data having periodicity. The present invention includes the following: an image input unit to input image signal; a first predictive converter which converts relation between the pixel value of a target pixel in the image signal inputted through the image input part and that of another pixel into a first prediction value; a first encoder which generates intermediate data by encoding the first prediction value output from the first predictive converter; a second predictive converter which converts relation between a target symbol among symbols making up the intermediate data generated by the first encoder and another symbol into a second prediction value; and a second encoder which generates an encoded signal by encoding the second prediction value output from the second predictive converter.

Abstract: A color image of a dot-sequential system is converted into a color image of a field-sequential system and a color image can be encoded/decoded at a high speed with a high compression ratio. A pixel value of image data of a dot-sequential system is sequentially inputted to a reference area generating means, and the reference area generating means outputs target pixel data and reference area data. A same pixel value distributing and generating means generates and outputs a same pixel value distribution from the target pixel data and the reference area data. A predictive information encoding means encode data in accordance with an encoding generating table, and outputs predictive information encoded data and an encoding result signal. A dot-sequential/field-sequential image converting means converts pixel data of dot-sequential system into image data of field-sequential system when data cannot be encoded.

Abstract: An image processing apparatus and method rotates an image at any angle during frequency transform of image coding or image decoding. A basis calculator calculates transform bases according to a rotation angle parameter received from a parameter input unit, and outputs the calculated transform bases to a transform unit. A coordinate calculator calculates input block coordinates according to a rotation parameter, and outputs the calculated input block coordinates to an image input unit. The image input unit extracts an input image block from an input image in accordance with the input block coordinates, and outputs the extracted input image block to a transform unit. The transform unit transforms the input image block by using the transform bases, and outputs transform coefficients to an entropy encoder. The entropy encoder performs entropy coding of the transform coefficients, and outputs code data to an image output unit. Inverse processes are performed for decoding.

Abstract: A coding apparatus and decoding apparatus for easily generating an adaptive Huffman code. A frequency counting element possesses a counter that counts the appearance frequency of a preset dominant symbol candidate included in an input data. A dominant symbol selecting unit selects from a frequency data, data having a larger frequency than a predetermined threshold value and sends the selected data to a code assigning element as a dominant symbol frequency data. A fixed code word memory stores a previously generated Huffman code and sends it to the code assigning element as a fixed code word data. The code assigning element generates a Huffman code for the dominant symbol and synthesizes the Huffman code and the fixed code word data stored in the fixed code word memory to obtain the Huffman code for the whole data. The input data is coded using the Huffman code and an intermediate symbol data. The intermediate symbol data and a Huffman code table data are sent in a coded state.

Abstract: The present invention provides a coding apparatus, decoding apparatus, coding-decoding apparatus and corresponding methods which easily generate an adaptive Huffman code. The coding apparatus includes a frequency counting element that counts the frequency of appearance of symbols in input data and a symbol selecting element that selects the data having a frequency larger than a predetermined threshold value as dominant symbol frequency data and transfers the dominant symbol frequency data to a code assigning element. The coding apparatus further includes a fixed code word memory that stores the Huffman codes prepared in advance and transfers them to the code assigning element as fixed code word data. The code assigning element generates the Huffman codes for the dominant symbols and synthesizes the Huffman codes and the fixed code word data stored in the fixed code word memory to obtain the Huffman code as a whole. The obtained Huffman code is stored in a code word memory.

Abstract: Disclosed herein are easy-to-realize multivalued image coding and decoding devices, each of which is capable of reducing memories in number while the accuracy of calculations necessary upon coding and decoding is being held and relaxing a probability estimate. An image disassembler disassembles a bit string indicative of pixels into a plurality of parts in response to image data inputted from an image input unit. Further, the image disassembler sends the value of each disassembled pixel to be coded and the value of each disassembled pixel for reference to an image analyzer as disassembled image data. The image analyzer sends the value of each disassembled pixel to be coded to a coding unit as disassembled pixel-value data and transmits the value of the reference pixel to a probability estimate unit as status data. The probability estimate unit sends probability estimate data corresponding to the status data to the coding unit.

Abstract: An image signal encoding apparatus reads an image from an original and converts the image into color data values including lightness and chromaticity components. The data values are stored and divided into pixel blocks with data values of lightness components and pixel blocks with data values of chromaticity components. Average lightness component data values are computed for pixel blocks of lightness components and average chromaticity data values are computed for pixel blocks of chromaticity components. A region determination is made whether the pixel blocks correspond to color, monochrome or background region in the original based on the average pixel block data values of lightness components and chromaticity components. A switch outputs the lightness pixel block data values during the region determination, and outputs the lightness and chromaticity pixel block data values after the region determination.

Abstract: Disclosed herein are easy-to-realize multivalued image coding and decoding devices, each of which is capable of reducing memories in number while the accuracy of calculations necessary upon coding and decoding is being held and relaxing a probability estimate. An image disassembler disassembles a bit string indicative of pixels into a plurality of parts in response to image data inputted from an image input unit. Further, the image disassembler sends the value of each disassembled pixel to be coded and the value of each disassembled pixel for reference to an image analyzer as disassembled image data. The image analyzer sends the value of each disassembled pixel to be coded to a coding unit as disassembled pixel-value data and transmits the value of the reference pixel to a probability estimate unit as status data. The probability estimate unit sends probability estimate data corresponding to the status data to the coding unit.

Abstract: 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.