|Image Processing Toolbox User's Guide|
Computing the Frequency Response of a Filter
freqz2 function computes the frequency response for a two-dimensional filter. With no output arguments,
freqz2 creates a mesh plot of the frequency response. For example, consider this FIR filter,
This command computes and displays the 64-by-64 point frequency response of
Frequency Response of a Two-Dimensional Filter
To obtain the frequency response matrix
H and the frequency point vectors
f2, use output arguments
freqz2 normalizes the frequencies
f2 so that the value 1.0 corresponds to half the sampling frequency, or radians.
For a simple
n response, as shown above,
freqz2 uses the two-dimensional fast Fourier transform function
fft2. You can also specify vectors of arbitrary frequency points, but in this case
freqz2 uses a slower algorithm.
See Fourier Transform for more information about the fast Fourier transform and its application to linear filtering and filter design.
|Creating the Desired Frequency Response Matrix||Transforms|
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