close all;
clear all; clc;
i = imread('(HTC-1-M7)1.jpg');
corner1 = i(1:512,1:512,2);
corner2 = i(2448-512:2448,size(i,2)-512:size(i,2),2);
B = gather( diff(gpuArray(i(:,:,2)),2,2) );
B1=gather( diff(gpuArray(corner1),2,2) );
B2 = gather( diff(gpuArray(corner2),2,2) );
ym = abs(fft(mean(B)));
ym1 = abs(fft(mean(B1)));
ym2 = abs(fft(mean(B2)));

subplot(3,1,1);
plot(ym);
subplot(3,1,2);
plot(ym1);
subplot(3,1,3);
plot(ym2)