Microscanning is a method for increasing resolution of
digital camera
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices ...
s. With the
color co-site sampling identically colored pixels in several frames of the specimen, obtained by moving the sensor with a
piezo mechanism in a regular
raster, are combined to a sharp resulting image. The detector, however, can also be
translated
Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transla ...
by a fraction of the pixel pitch: this way also the interstitial space between sensor pixels gets scanned and the number of pixels in the final image is increased. Three positions on the x and y axes increase the image size by a factor of 9, for instance from the common 1388 x 1040 pixels to 4164 x 3120 pixels (se
Sony ICX285 series. The
color co-site sampling used at the same time ensures correct reproduction of colors at the
pixel density produced.
Whether the
spatial resolution
In physics and geosciences, the term spatial resolution refers to distance between independent measurements, or the physical dimension that represents a pixel of the image. While in some instruments, like cameras and telescopes, spatial resolut ...
will increase accordingly, depends on the
optical resolution of the complete system. The relevant parameter is the resolving power, i.e. how many lines per mm can be resolved. It increases with the aperture of the optical system and is inversely proportional to its magnification. As a result, a low-resolution camera with 500 lines would be enough for an 100X objective with 0.9 aperture. On the other hand, low-magnification objectives profit most from micro scanning: for instance for a 2,5X objective with N.A.=0.12 cameras with as high as 2500 lines resolution could be used.
References
* European patent EP0396687 (1989-10-26), Reimar Lenz
Optoelectronic image sensor
External links
Microscanning: how does it work?
Digital photography