Demo iadftmatrixexamples

Demonstrate the kernel matrix for the DFT Transform.

Script

Kernel images generated

Imaginary and real parts of the DFT kernel.

1. from ia636 import iadftmatrix, ianormalize, iaplot
2. 
3. A = iadftmatrix(128)
4. adshow(ianormalize(A.real),'A.real')
5. adshow(ianormalize(A.imag),'A.imag')

A.real

A.imag

Four first lines

Four first lines from real and imaginary parts of the kernel matrix. Observe the increasing frequencies of the senoidals
(imaginary part) and cossenoidals (real part).
1. adshow(iaplot([A.real[0,:],A.imag[0,:]]),'u = 0')
2. adshow(iaplot([A.real[1,:],A.imag[1,:]]),'u = 1')
3. adshow(iaplot([A.real[2,:],A.imag[2,:]]),'u = 2')
4. adshow(iaplot([A.real[3,:],A.imag[3,:]]),'u = 3')

u = 0

u = 1

u = 2

u = 3

Showing complex conjugates

1. adshow(iaplot([A.real[ 0,:],A.imag[ 0,:]]),'u = 0')
2. adshow(iaplot([A.real[-1,:],A.imag[-1,:]]),'u = -1')
3. adshow(iaplot([A.real[-2,:],A.imag[-2,:]]),'u = -2')
4. adshow(iaplot([A.real[-3,:],A.imag[-3,:]]),'u = -3')

u = 0

u = -1

u = -2

u = -3

See also