Divide a data set (of 201*360) into M*N sub data (rectangular in fourier) and to apply FFT on each sub data sets

Dear MATALB community,

I need to divide a data of 201*360 into M*N sub data set which should be rectangular and then apply FFT on each data set.

aps = N;

n_aps = 360/aps;

fpoints=201;

N_fpoint = M;

for i=1:n_aps

data_s(:,:,i)=data((i-1)*aps+1:i*aps,:); % to make sub data sets

data_fft_s(:,:,i)=fft2(data_s(:,:,i),360,fpoints); % to apply fft

end

I need to divide data with M*N orientation and divide data on both dimension, since above mentioned code give different results.

I need guidance, please provide your valueable remarks. Thanks in advance.

Answer 1

[yanqi liu]

clc; clear all; close all;
data = imresize(imread('cameraman.tif'), [201, 360], 'bilinear');
M = 10; N = 5;
%  apply FFT on each data set.
data2=blockproc(data,[M N],@myfun);
figure;
subplot(1,2,1); imshow(data,[]);
subplot(1,2,2); imshow(data2,[]);

figure;
subplot(1,2,1); imshow(data,[]);
subplot(1,2,2); imshow(log(abs(data2)),[]);

function y=myfun(block_struct) 
y = real(fft2(double(block_struct.data)));
end

[Amjad Iqbal]

@yanqi liu Thank you so much, this works nicely.