IMAGING SYSTEM, SPACIAL FILTER AND DESIGN METHOD FOR IMAGING SYSTEM INCLUDING SUCH SPACIAL FILTER

摘要

PROBLEM TO BE SOLVED: To provide a design method for an imaging system including such a spatial filter as correcting the depth of field or the focal depth of the imaging system depending on the presence or absence of digital image post-processing.SOLUTION: In a method for designing an imaging system including an optical system 10 having a longitudinal optical axis, an image sensor 30, and a spatial filter, the imaging system is configured to form the image of a focal surface 20 on the image sensor 30. The optical transfer function of the optical system combined with the spatial filter is calculated as the function of spatial frequency of the image on one hand, and the function of focus failure on the other hand, and determines the contrast map and phase map of the optical system combined with the pupil function of the spatial filter. The contrast map and phase map are the function of spatial frequency on one hand, and the function of focus failure on the other hand. Based on these maps, the value of the range in the longitudinal direction of the focal depth domain of the imaging system in the spatial frequency effective range and the average contrast are determined.SELECTED DRAWING: Figure 1