The Uncertainty of Scanner Illumination II

摘要

In a preliminary report, we showed the impact of the integrating cavity effect for a typical document scanner with optical ray tracing. The effect was demonstrated by examining the illumination profile after accounting for multiple reflections from the document surface, the contact platen glass surfaces and all reflectors used in the illumination assembly. We identified that the platen glass can contribute just as much as the illumination assembly to the effect. In the second phase, we built an actual scanner model to verify the ray tracing results and the effect. The verification was accomplished by examining the edge profile differences of the scan images of unique patterns before and after a certain reflection component was removed with two different scan configurations. The experimental results are consistent with the simulation results in general.