The development of microscopes is nearly fixed since the introduction of confocal microscopy. The credit-point of confocal microscopy is the low depth of focus. But a small depth of focus is very often a problem in conventional light microscopy, because the objects are higher than the depth of focus. There is a physical limitation based on the numerical aperture (NA) of the objective lens of the microscope. The connection of the conventional light microscope, video technique and computers open new fields of applications for the microscopy. It is possible to generate an image containing focused areas from series of images of different focus- or z- positions. In this way it is possible to extend the depth of focus without a physical limitation by the NA of the objective lens. The connection of microscope, video and PC also opens the field of high resolution low light color applications, like fluorescence in situ hybridization (FISH). Image processing technology enables the enhancement of contrast for objects with a very low contrast. And such a system also opens the way for a view to objects with small motion, like processes of growing of biological objects.
Volker Tympel, Volker Tympel,
"New high-level image capture system for conventional light microscopy", Proc. SPIE 2707, Medical Imaging 1996: Image Display, (15 April 1996); doi: 10.1117/12.238483; https://doi.org/10.1117/12.238483