Abstract: The present invention discloses a method and apparatus for hierarchical coding of image data using a typical prediction TP if a 2.times.2 array of pixels can be reduced to coded pixel. The present invention uses a TP flag, TP discrimination and a two line delay. Accordingly, the hierarchical coding can be realized by a small amount of hardware. According to deterministic prediction DP, if there is a decision that the image data may be reduced then the value of the pixel can be predicted from a reduced pixel (low resolution data) and surrounding pixels (high resolution data) which are extracted in advance. If the pixel to be coded is one that can be uniquely determined this pixel is excluded form coding.

Abstract: In an image encoding method in which a pixel of interest is predicted with reference to a plurality of pixels near the pixel of interest to be encoded, and encoding is performed on the basis of coincidence/noncoincidence between the predicted pixel and the pixel of interest, a parameter for predicting a pixel is changed on the basis of a rate of coincidence/noncoincidence of the predicted pixel and the pixel of interest.

Abstract: An image treatment apparatus comprising: an input device for inputting image data; a setting circuit serving as a reference when the image data is quantized in accordance with the image data input by the input device; a quantizing circuit for quantizing the image data; and a device for outputting an image in accordance with the result of treatment performed by the quantizing circuit, wherein the quantizing circuit performs the quantization by correcting the error between the image data input by the input device and the image output by the outputting device.

Abstract: An image data coding method for a case where image data are transmitted or filed upon being binary coded includes steps of replacing a predetermined pixel by a predicted value predicted by a plurality of pixels peripheral to the predetermined pixel, in conformance with a coded image data compression technique, and performing binary coding while dispersing an error, which is generated by the replacement, among peripheral pixels. Also provided are a variety of image data coding apparatus for practicing this image data coding method. The invention makes it possible to perform binary coding and compression of half-tone image data very efficiently.

Abstract: In an image encoding method in which a pixel of interest is predicted with reference to a plurality of pixels near the pixel of interest to be encoded, and encoding is performed on the basis of coincidence/noncoincidence between the predicted pixel and the pixel of interest, a parameter for predicting a pixel is changed on the basis of a rate of coincidence/noncoincidence of the predicted pixel and the pixel of interest.

Abstract: An image processing apparatus extracts an edge or line portion of an image, judges grayness of the image, and processes the image according to outputs of the means used for the edge- or line-extraction and grayness-determination. The further processing may, for example, comprise undercolor removal and/or black-addition. Edge extraction can be performed by use of a Laplacian. The grayness can be judged by, for example, providing a colorlessness signal formed from two color component signals. Extraction of a line region, instead of Laplacian edge extraction, can be performed, for example, by use of an Hadamard transformation. Also, the invention more generally includes detecting grayness of an image, detecting other characteristics of the image, and judging additional characteristics of the image according to the first two determinations.

Abstract: An image encoding apparatus includes a smoothing circuit for smoothing a binary image to be encoded, a binary-encoding circuit for binary-encoding the image smoothed by the smoothing circuit, a sampling circuit for sub-sampling the image binary-encoded by the binary-encoding circuit, and an encoding circuit for encoding the binary image sub-sampled by the sampling circuit. A degree of smoothness of an image by the smoothing circuit and a threshold value for a binary-encoding operation of the binary-encoding circuit can be varied.

Abstract: An image processing apparatus for digitizing an analog image by dispersing the digitizing error to the surrounding areas. The characteristics or edge of the analog imnage are identified, and the error dispersing area is varied according to the result of identification, thus enabling reproduction of the image with high quality regardless of the nature of the original image.

Abstract: There is provided an improvement on the error dispersion method for binary digitizing of an image, in which an area of plural pixels is digitzed, and the error into the digitizing is dispersed in a neighboring area of plural pixels. In the latter area the digitization is conducted according to the image data of plural pixels and the error data dispersed into this area.

Abstract: An image processing apparatus such as a digital printer or digital facsimile apparatus for half tone processing input image data has: an input device to input image data indicative of a concentration of an image; a discriminating circuit to discriminate whether the input image data is smaller than a threshold value or not; a binarizing circuit to binarize the input image data into binary data of high and low levels; and a setting circuit to set the binary output of the image data to the low (0) level irrespective of the result of the binarization by the binarizing circuit when the input image data is determined to be smaller than the threshold value. The input device includes a reading circuit to read the original image and a generator to generate image data indicative of the original image concentration.

Abstract: There are provided an image processing method and apparatus for processing an image by digital signals and for reproducing the image with a high picture quality. The apparatus comprises: an input device to input a plurality of color image data; a first processor to perform a dotting process on the color image data input by the input device; and a second processor to digitize the color image data dot-processed by the first processor, wherein the first processor changes the dotting process for each of the color image data. With the apparatus, first and second features of the input image are detected and different dotting processes are executed in accordance with the first and second features, so that the image process can be executed at a high speed and a color image having excellent gradations and resolution can be obtained while suppressing the occurrence of a color moire.

Abstract: There is provided an image processing apparatus which handles an image as a digital signal, comprising: an input device to input image data indicative of a concentration of an image; a binarization circuit to binarize the input image data; a positive/negative state detection circuit to detect whether error data generated when the image data is binarized by the binarization circuit is in a positive state or a negative state; and a selector to select whether the error data generated upon binarization is to be corrected or not, on the basis of the positive or negative state of the error data. The input device has a generator to read an original and generate an analog image signal and a converter to convert the analog image signal into the digital image data. The error data is the difference between the input image data and the binary data produced by the binarization circuit.

Abstract: An image processing apparatus of this invention includes a digital data output device for outputting bi-level image data, a bi-level processor for converting the bi-level image data into multi-level (e.g., 8-bit) image data, a multi-level processor for performing spatial filter processing with respect to the multi-level image data output from the bi-level processor, and a PWM circuit for processing the multi-level image data output from the multi-level processor using a pattern signal of a predetermined cycle and generating a PWM signal.

Abstract: A color image information processing apparatus includes a plurality of color separation circuits for separating input information into image information for the respective colors on the basis of constants and a CPU for comparing the image information for each color with a predetermined value, wherein each separation circuit changes a corresponding constant in accordance with the result of the comparison by the CPU.

Abstract: There is an image processing apparatus for digitally processing an image. This apparatus comprises: a binarization circuit to binarize image data by a predetermined threshold value; a processor to correct errors generated in binarization; a first detector to detect an edge direction of the image from the image data; and a second detector to detect an edge quantum of the image from the image data. The process corrects the error data in accordance with the edge direction detected by the first detector or the edge quantum detected by the second detector. The errors to be corrected by the processor are the errors between the output concentration data after the binarization and the image concentration data. The processor adds weight coefficients to the error data in a predetermined range stored in a memory and then adds the weighted error data to image data to be newly binarized. The sum of the weight coefficients which are used in the weighting process is set to "1".

Abstract: An image processing apparatus for digitizing an analog image by dispersing the digitizing error to the surrounding areas. The characteristics or edge of the analog image are identified, and the error dispersing area is varied according to the result of identification, thus enabling reproduction of the image with high quality regardless of the nature of the original image.