Kimiaki YAMAMOTO

KM OptLab, 1706-12 Kanoya, Hachioji, Tokyo 193-0815, Japan

(Received March 15, 2014; Accepted August 11, 2014)

The depth of field is investigated for an imaging system in which optical imaging and electronic devices, such as an electronic sensor and a display, are combined. When the spatial frequency of pixels in the electronic devices is higher than the cut-off frequency of the optical system, it is shown that the depth of field is almost the same as that of the optical system itself. In the case where the spatial frequency is lower than the cut-off frequency of the optical system, the depth of field increases, and the features of the increase are shown in imaging systems both with and without an optical low-pass filter.

Key words: depth of field, digital microscopes