M. Hattori and S. Komatsu: The endoscopic application of the deconvolution filter set method, Optics and Lasers in Biomedicine and Culture (Proc. Optics Within Life Sciences V) (Springer-Verlag, July 2000), 33-36.

We propose the combination of the endoscopic system with the deconvolution filter set method which enables both the image recovery and the defocus amount evaluation of a defocussed image. This combination extends the focus range of the small, fixed-focus simple optical systems, and is expected to reduce the operating time by omitting the focus adjustment in situ. In this paper, some experimental results of the focus extension and object distance measurement are shown.