This will do it:
clc; % Clear the command window.
clearvars;
close all; % Close all figures (except those of imtool.)
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;fontSize = 22;
s = load('image_data.mat')
D = s.D;
realD = abs(real(D));
imagD = abs(imag(D));
subplot(2, 3, 1);
imshow(realD, []);
axis square
title('Real Image', 'FontSize', fontSize);
impixelinfo();
subplot(2, 3, 2);
histogram(realD);
grid on;
title('Histogram of Real Image', 'FontSize', fontSize);
subplot(2, 3, 4);
imshow(imagD, []);
axis square
title('Imaginary Image', 'FontSize', fontSize);
impixelinfo();
subplot(2, 3, 5);
histogram(imagD);
grid on;
title('Histogram of Imaginary Image', 'FontSize', fontSize);
backgroundValueR = 5e8;
backgroundValueI = 3e8;
binaryImageR = realD > backgroundValueR;
binaryImageI = imagD > backgroundValueI;
subplot(2, 3, 3);
imshow(binaryImageR, []);
axis square
impixelinfo();
title('Real Image, binarized', 'FontSize', fontSize);
subplot(2, 3, 6);
imshow(binaryImageI, []);
axis square
impixelinfo();
title('Imaginary Image, binarized', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
% Apply the mask
% Mask the image using bsxfun() function to multiply the mask by each channel individually.
maskedRealImage = bsxfun(@times, realD, cast(binaryImageR, 'like', realD));
maskedImagImage = bsxfun(@times, imagD, cast(binaryImageI, 'like', imagD));
figure;
subplot(2, 1, 1);
imshow(maskedRealImage, []);
axis square
impixelinfo();
title('Masked Real Image, binarized', 'FontSize', fontSize);
subplot(2, 1, 2);
imshow(maskedImagImage, []);
axis square
impixelinfo();
title('Masked Imaginary Image, binarized', 'FontSize', fontSize);
