Effect of camera gamma and gain on the line shape and axial resolution in a confocal microscope setup

Abstract

Confocal microscopy is an important state-of-art in the field of optical microscopy with wide ranging applications in surface microstructuring of metal and non-metal surfaces, finger print observations in forensic sciences, 3D volume rendering of biological specimen etc. The advancement in digital image processing, availability of high speed computer with high memory size and simplicity of image grabbing technique enables the use of high sensitive CCD camera in confocal microscope setup. In addition to the inherent parameters of the confocal microscope such as the size of the confocal aperture, numerical aperture of the microscope objective etc., the camera parameters mainly camera gamma and gain affects the performance of the microscope. In the present paper the effect of camera gamma and gain on the contrast and shape of the detected target lines is studied experimentally through focal plane scanning of a 1951 USAF test target in a confocal microscope setup. The effect of camera gamma on the axial resolution of the confocal microscope setup is also studied experimentally through axial scanning with a mirror.