How to find the threshold of a matrix?

Iam working on FFT algorithm.The FFT is applied to an image and it resulted in complex number matrix.Now I have to find threshold of the FFT resulted matrix and set the values of matrix to zero which are below threshold.Then apply IFFT to reconstruct.But Iam not able to find threshold of matrix.Any help appreciated.Thanks in advance

Answer 1

[Greg Heath]

rng(0)

x = randn(1,32);

X = fft(x);

absX = abs(X);

M = max(absX);

absX(absX < M/100) = 0;

z = ifft(absX.*exp(i*angle(X)));

err = max(abs(z-x))

err =

4.4419e-016

Thank you for formally accepting my answer

Greg