Page 337 - Fundamentals of Light Microscopy and Electronic Imaging

320 APPENDIX I

mm and no relay lens (M 1), f (100 800)/(1.2 15.875) 4200
relay H
cycles/mm. This corresponds to a distance in the specimen of 1000 m/mm
(1/4200) or 0.24 m. (3) The addition of a VCR significantly degrades the image due
to a decrease in the system bandwidth, where bandwidth BW is given: 1/BW of system
2
1/(BW each component) . Given that a bandwidth of 10 MHz is required to rep-
resent 800 lines horizontal resolution, and the bandwidths in MHz for the camera and
VCR are 15 and 6 MHz, respectively, the system bandwidth is 3.9 MHz, which corre-
sponds to 312 lines resolution, a 2.5-fold decrease in spatial resolution. (4) To avoid
image degradation, the image should be magnified by employment of an intervening
booster lens or “TV lens.”