Patent ID: 6753914
Filing Date: 2004-06-22
Classification: H04N

Abstract:
An imaging system, comprising:a line discrete-pixel array, including an array of light-sensitive pixel sensors, for absorbing light during an interval and producing analog electrical signals in response to said light, and for transferring said signals to an output port, said signals being representative of an image; means for illuminating an object to be imaged, and for causing illumination of said object to excite said array, the image resulting from said image-representative signals being subject to distortion arising from at least one of (a) pixel-to-pixel variations in sensitivity of said array, (b) image illumination variations, (c) channel errors in multichannel arrays, and (d) other sources, which result in distortion of an image generated from said signals; means for scanning said object relative to said array, so as to produce a sequence of uncorrected signals associated with each pixel of said array across said scanned object; color-scale correction means coupled to said array, for receiving said uncorrected signals, and for correcting the signal representing each uncorrected pixel by a correction factor, said correction factor being established by, (a) with a particular color object before said array, averaging the value of said uncorrected signal for each of said pixels of said array over at least a portion of said scanned object, to thereby produce averaged uncorrected signals for each pixel, (b) for each of said pixels of said array, determining an ideal averaged uncorrected signal value produced by an ideal pixel of an ideal imager, said correction factor being the factor required to bring the averaged uncorrected signal value to said ideal signal value; and, threshold means coupled to said color-scale correction means, for enabling said color-scale correction means when the uncorrected signal value for a particular pixel represents a color scale value having a value lying on a first side of a threshold value lying between said ideal averaged uncorrected signal value for a particular color and said black level, and for reducing the correction provided by said color-scale correction means when the uncorrected signal value for a particular pixel represents a color scale value lying on a second side of said threshold value.