Oct 30 2014
Optical resolution is the physical resolution at which an imaging device can capture an image. The term is mostly used in connection to optical scanners and digital cameras.
Optical resolution has the ability to resolve detail in the object that is being imaged via an imaging system.
Imaging systems contain many individual components such as lens and recording and display parts. These individual components along with the environment where the image is captured will have an effect on the optical resolution of the system.
Another type of resolution related to imaging devices is interpolated resolution. It indicates the resolution that the device can yield through interpolation, which is the process of producing intermediate values based on known values.
Most scanners generally provide an optical resolution of 300 dpi, and an interpolated resolution of up to 4,800 dpi. These resolutions enable the scanner to actually capture 90,000 pixels per square inch. Based on the values of these pixels, 15 additional pixels can be added in-between each pair of known values to yield a higher resolution.
Optical resolution provides the measure of how much information about the image the scanner can capture, and therefore should be considered while evaluating a scanner.
The optical resolution of a monochromatic source can be measured as full- width-half-maximum (FWHM) and depends upon the groove density (mm-1) of a grating and diameter of an entrance optic.
For instance, while configuring a spectrometer, optical resolution can be increased with the increase in the groove density of a grating (at the expense of spectral range and signal strength). Similarly, the optical resolution can be increased with the decrease in slit width or fiber diameter (at the expense of signal strength).
References and Further Reading