Abstract: In a method and apparatus for converting digitized luminance-chrominance color space signals to digitized RGB color space signals, a first combining unit generates a plurality of predetermined linear combinations of the chrominance color space signals received by a multiplexed multiplication unit which includes no more than two look-up tables that contain digitized transformation values for performing matrix multiplications of the linear combinations of the chrominance color space signals. A second combining unit linearly combines the digitized transformation values outputted by the multiplexed multiplication unit and a predetermined binary combination of the luminance color space signal in a first predetermined manner to generate three RGB color combination signals. A third combining unit linearly combines the RGB color combination signals in a second predetermined manner to obtain the RGB color space signals.

Abstract: Physiological primary colors, which correspond to tristimulus values of each of picture elements of an image on a hard copy, are obtained. A parameter, which represents the degree of incomplete chromatic adaptation, is determined in accordance with a correlated color temperature of a white point of a CRT display device, on which the image is to be displayed. Temporary tristimulus values, which are to be reproduced on the CRT display device, are derived in accordance with the parameter. From the temporary tristimulus values, perception values relating to lightness, color vividness and hue, such as metric lightness, metric chroma, and a metric hue angle in the LAB-color space are calculated by taking the white point of the CRT display device as a viewing illuminance. The tristimulus values of the image are then transformed into the tristimulus values on the display device, and a soft copy image is formed on the display device in accordance with the transformed tristimulus values.

Abstract: The present invention relates to a method of converting signal components of one of a first input three component color model signal and a second input three component color model signal to either one of the first or second three component color model comprised of matrix multiplying input signal components with an array of predetermined transformation parameters to form a multiplied set, vector adding the multiplied set with a predetermined group of offset vectors, whereby signal components of the output signal are produced.

Abstract: A subject color and a non-subject color of color change operation are specified and then a first color vector representing the subject color and a second color vector representing the non-subject color are obtained. A substitute color for replacing a component of the subject color is further specified, and a color vector representing the substitute color is obtained. A third color vector independent of the first and second color vectors is further determined. A color of each pixel in an original color image is expressed by linear combination of the first through third color vectors, thereby obtaining first through third coefficients for the first through the third color vectors. If the first coefficient is positive, the first color vector is replaced by the substitute color vector. The pixel color after the color change operation is then determined by producing a composite vector using the first through the third coefficients.

Abstract: The present invention provides color conversion apparatus that prevents overflow in color reproduction, changes in hue, and the deterioration of gradation to improve image quality. The present color conversion apparatus inputs to itself luminance and color difference signals, sets a reference value not less than the maximum level of the luminance signal, converts the luminance and color difference signals into primary color signals, detects the maximum value of the primary color signals for each pixel, lowers the levels of the color difference signals if the maximum value is over the reference value to locate the amplitude of the primary color signals not greater than the reference value.

Abstract: The present invention provides color conversion apparatus that prevents overflow in color reproduction, changes in hue, and the deterioration of gradation to improve image quality. The present color conversion apparatus inputs to itself luminance and color difference signals, sets a reference value not less than the maximum level of the luminance signal, converts the luminance and color difference signals into primary color signals, detects the maximum value of the primary color signals for each pixel, lowers the levels of the color difference signals if the maximum value is over the reference value to locate the amplitude of the primary color signals not greater than the reference value.

Abstract: A processing system operates on data words each having first and second portions. A first memory stores the first portion of a first data word accessible by a first set of address bits received at first address inputs and a second set of address bits received at second address inputs, and stores the second portion of a second word accessible by the first set of address bits received at the first address inputs and a third set of address bits received at the second address inputs. A second memory stores the first portion of the second data word accessible by a first set of address bits received at first address inputs and a second set of bits received at second address input, and stores the second portion of the first word accessible by the first set of address bits received at the first address inputs and a third set of address bits received at the second address inputs. A first access mode accesses a selected one of the first and second portions of both the first and second words.

Abstract: Color image processing method and apparatus for suppressing side effects of a chrominance emphasizing process are provided. A chrominance C of an original color image is detected by a chrominance detector. A luminousness V of the original color image is detected by a luminousness detector. A parameter selector selects chrominance conversion parameters on the basis of the chrominance C and luminousness V to generate a selected parameter. A chrominance converter executes the chrominance conversion by chrominance conversion parameters a to i. It is possible to suppress a side effect such that the color deviation becomes conspicuous in a portion of small chrominance and luminousness due to the execution of the chrominance emphasizing process. Thus, image data of a high quality can be obtained.

Abstract: A method and apparatus is disclosed for forming a binary level output signal which has a single transition representative of a threshold crossing in a sensor output signal. The sensor output signal is applied to the inputs of two signal processing circuits, the first of which develops a first signal having a relatively fast transition representing the threshold crossing. The second circuit develops a second output signal that is representative of an integrated version of the sensor signal. In the preferred embodiment, a flip-flop receives the first signal at a clock input and the second signal at a data input. The flip-flop's set input may also receive the second signal. The resultant output signal from the flip-flop has but a single transition representing the threshold crossing, irrespective of noise-induced threshold crossings in the sensor output signal.