New High-resolution Technique of Image Reading Using LMSType Spectrum Filter

Abstract

This paper proposes a new technique of image reading for printed material using a one-chip image sensor that enables high resolution and solves the problem of false colors around pattern edges. To achieve this, the technique adopts a novel method that produces a color component value of a pixel that is not sampled based on the supposition that there is only one color dot in the background color of printed matter in small areas such as the aperture areas of the pixels of the image sensor. Based on this supposition, we derive the linear relationship between the color component and luminance in such small areas. In addition to using this linear relationship, using a color filter with a wide band transmission spectrum also contributes to achieving high resolution with this technique. We conducted a simulation where we used an LMS-type color filter as a wideband spectrum filter. The results from the simulation demonstrated the effectiveness of this method indicating that we could obtain high resolution for all color component signals as high that of a 3-chip color image sensor and it could improve color reproductivity around pattern edges.