Image scanning microscopy

Confocal imaging is established as a useful technique in numerous application areas, including microscopy, surface profiling, and three-dimensional (3D) imaging. Its advantages include improved spatial resolution, and an optical sectioning property giving depth information, as well as allowing penetration into scattering media such as biological tissue. For materials or industrial applications, the back-scattered light is measured by a single element detector via a small pinhole. In biomedical applications, a fluorescence mode is usually used. However, in a fluorescence mode the signal is usually weak, so the pinhole must be enlarged, thus losing the resolution advantage. Now there are several commercial microscope systems that retain the resolution improvement while increasing the detected signal, by replacing the single element detector with a detector array, followed by computer processing of the measured signals. The basic principle of image scanning microscopy system is pixel reassignment, where the signal is reassigned to its correct origin. It seems likely that this approach will replace the original implementation using a single confocal pinhole.