What is a point spread function (PSF)?
A point spread function is a mathematical term for the impulse response of a system. When the term “point spread function” is used in connection with an optical system it means the impulse or point response of an optical system to a point input. A single point of light is focused by the lens into a complex shape known as a point spread function (PSF). The shape of the PSF depends upon light wavelength, lens numerical aperture (NA), and the optical aberration of the lens. By knowing the shape of the PSF the operator can remove the excess light from any image plane thus producing a high resolution image.
