Patent ID: 7256380

Claim:
An image reading apparatus, comprising an image sensor unit comprising a first photoconverter comprising a first array of first light receiving elements, the first photoconverter for photoelectrically converting light of a first color from a source image for outputting a first color signal a second photoconverter comprising a second array of second light receiving elements, the second photoconverter for photoelectrically converting light of a second color from a source image for outputting a second color signal a third photoconverter comprising a third array of third light receiving elements, the third photoconverter for photoelectrically converting light of a third color from a source image for outputting a third color signal a fourth photoconverter comprising a fourth array of fourth light receiving elements, the fourth photoconverter for photoelectrically converting monochromatic light from the source image for outputting a monochrome signal an A/D converter unit to convert the first, second, and third color signals into respective first, second, and third digitized color signals each having a first number of bits convert the monochrome signal to a digitized monochrome signal having a second number of bits greater than the first number of bits a signal correction unit to produce enhanced color signals use the digitized monochrome signal to modify the first, second, and third digitized color signals to produce the enhanced color signals.