![]() ![]() The narrower the aperture of a lens the more likely the PSF is dominated by diffraction. ![]() The interplay between diffraction and aberration can be characterised by the point spread function (PSF). Light passing through the lens interferes with itself creating a ring-shape diffraction pattern, known as the Airy pattern, if the wavefront of the transmitted light is taken to be spherical or plane over the exit aperture. The lens' circular aperture is analogous to a two-dimensional version of the single-slit experiment. On the other hand, diffraction comes from the wave nature of light and is determined by the finite aperture of the optical elements. Aberrations can be explained by geometrical optics and can in principle be solved by increasing the optical quality of the system. These two phenomena have different origins and are unrelated. The imaging system's resolution can be limited either by aberration or by diffraction causing blurring of the image. ![]() Points closer than the Rayleigh criterion (bottom) are difficult to distinguish. Points far apart (top) or meeting the Rayleigh criterion (middle) can be distinguished. In scientific analysis, in general, the term "resolution" is used to describe the precision with which any instrument measures and records (in an image or spectrum) any variable in the specimen or sample under study.Īiry diffraction patterns generated by light from two point sources passing through a circular aperture, such as the pupil of the eye. As explained below, diffraction-limited resolution is defined by the Rayleigh criterion as the angular separation of two point sources when the maximum of each source lies in the first minimum of the diffraction pattern ( Airy disk) of the other. The term resolution or minimum resolvable distance is the minimum distance between distinguishable objects in an image, although the term is loosely used by many users of microscopes and telescopes to describe resolving power. Resolving power is the ability of an imaging device to separate (i.e., to see as distinct) points of an object that are located at a small angular distance or it is the power of an optical instrument to separate far away objects, that are close together, into individual images.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |