In mathematics, physics, and engineering, **spatial frequency** is a characteristic of any structure that is periodic across position in space. The spatial frequency is a measure of how often sinusoidal components (as determined by the Fourier transform) of the structure repeat per unit of distance. The SI unit of spatial frequency is cycles per meter. In image processing applications, spatial frequency is often expressed in units of cycles per millimeter and sometimes incorrectly in units of line pairs per millimeter (incorrect since a line pair may describe a square wave but not a sinusoidal wave).

In wave mechanics, the spatial frequency is commonly denoted by or sometimes, although the latter is also used to represent temporal frequency. It is related to the wavelength by the formula

Likewise, the wave number (e.g. in radians per meter) is related to spatial frequency and wavelength by

Read more about Spatial Frequency: Visual Perception, See Also

### Other articles related to "spatial frequency, frequency, spatial":

... This data is graphed against the

**spatial frequency**data ...

**spatial frequency**curve to remove any trends ... The 50% cutoff

**frequency**is determined to yield the corresponding

**spatial frequency**...

... The power spectrum of the CIB is usually presented in a

**spatial frequency**vs ... a characteristic power spectrum of a power-law (that of a fractal

**spatial**structure) P(f) = P0(f/f0)α, where P is the fluctuation power at the

**spatial frequency**f, P0 is the ... which is much steeper than the power spectrum of the CIB at low

**spatial**frequencies ...

... see that the resulting intensity is made of a sinus law with a high "

**spatial frequency**" (wave number) which is the average of the

**spatial**frequencies of the two patterns ... The wavelength λ of this component is the inverse of the

**spatial frequency**if we consider that's p1 = p and p2 = p+δp ...

... The

**spatial frequency**is the reciprocal of the period of the pattern in this image, normally measured in cycles/mm ... The contrast, normalised to make the contrast at zero

**spatial frequency**equal to unity, expressed as a function of

**spatial frequency**, is the definition of the modulation ...

### Famous quotes containing the word frequency:

“The *frequency* of personal questions grows in direct proportion to your increasing girth. . . . No one would ask a man such a personally invasive question as “Is your wife having natural childbirth or is she planning to be knocked out?” But someone might ask that of you. No matter how much you wish for privacy, your pregnancy is a public event to which everyone feels invited.”

—Jean Marzollo (20th century)