You are here : matlab → Image Processing → fwind2
# fwind2() - Image Processing

### Syntax

### Example

### Output / Return Value

### Limitations

### Alternatives / See Also

### Reference

Use fwind2 to design two-dimensional FIR filters using the window method. fwind2 uses a two-dimensional window specification to design a two-dimensional FIR filter based on the desired frequency response Hd. fwind2 works with two-dimensional windows; use fwind1 to work with one-dimensional windows.h = fwind2(Hd, win) produces the two-dimensional FIR filter h using an inverse Fourier transform of the desired frequency response Hd and multiplication by the window win. Hd is a matrix containing the desired frequency response at equally spaced points in the Cartesian plane. fwind2 returns h as a computational molecule, which is the appropriate form to use with filter2. h is the same size as win.For accurate results, use frequency points returned by freqspace to create Hd. (See the entry for freqspace for more information.)h = fwind2(f1, f2, Hd, win) lets you specify the desired frequency response Hd at arbitrary frequencies (f1 and f2) along the x- and y-axes. The frequency vectors f1 and f2 should be in the range -1.0 to 1.0, where 1.0 corresponds to half the sampling frequency, or π radians. h is the same size as win.

h = fwind2(Hd, win)h = fwind2(f1, f2, Hd, win)

[f1,f2] = freqspace(21,'meshgrid'); Hd = ones(21); r = sqrt(f1.^2 + f2.^2); Hd((r<0.1)|(r>0.5)) = 0; colormap(jet(64)) mesh(f1,f2,Hd)