In wave mechanics, the spatial frequency is related to the wavelength by The wave equation is an important partial differential equation which generally describes all kinds of waves, such as sound waves, light waves and water waves. ...
Likewise, the wave numberk is related to spatial frequency and wavelength by Wavenumber in most physical sciences is a wave property inversely related to wavelength, having units of inverse length. ...
As the spatialfrequency approaches very large values, the square wave response resembles that of a sinusoid, yielding graphs of the contrast transfer function and the modulation transfer function that are virtually identical.
At low spatialfrequencies, image contrast is the highest, but falls to zero as the spatialfrequency is increased beyond a certain point (drawn in Figure 2 as a reduction in amplitude produced in the image).
It is composed of sinusoidal patterns having a spatialfrequency range between 0.2 and 80 line pairs per millimeter with a grayscale optical density range varying between 0.2 and 1.2 and an 80 percent modulation of the sine waves.
The unit employed to express spatialfrequency is the number of cycles that fall within one degree of visual angle (each cycle is one dark and one light bar).
However, at intermediate spatialfrequencies, the contrast in the image is degraded by the butter on the lens.
If those objects contain only very low spatialfrequencies (very large objects) or only very high spatialfrequencies (very small objects or fine details), they will be less visible and their contrast will have to be high in order for those objects to be seen.
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