Question

MATLAB PROGRAMMING CHALLENGE

I'm looking to make a program to super-impose a rectangle over a selected part of an image. First, I need to use "uigetfile" to allow the user to select an image. Then show the image, and allow the user to select 2 points, to form a rectangle. Keep the image data in one variable, and make a copy to another. In the copy, put a red rectangle according to the selected points. Then copy in the original over the red rectangle, with a little offset from the selected points. Then show this version to the user. This way, the user will see the image with the outline of a red rectangle according to the selected points.

Thanks

Answer 1

Please find required MATLAB code along with necessary details in comments:

clear all; close all; clc;

% load an image
[file,path] = uigetfile('*.jpg');
if isequal(file,0)
disp('User selected Cancel');
else
disp(['User selected ', fullfile(path,file)]);
end

img=rgb2gray(imread(fullfile(path,file)));
[m,n]=size(img); % determine its size
imshow(img)
[x,y] = ginput(2);

% genearte window location
start_row=min(x); end_row=max(x);
start_col=min(y); end_col=max(y);

close all
figure;
copy_img=img;
imshow(copy_img); %show your image
hold on;
rectangle('Position', [start_row start_col end_row-start_row end_col-start_col] ,...
'EdgeColor', 'r',...
'LineWidth', 3,...
'LineStyle','-'); % draw rectangle on image

======================== SCREENSHOT OF CODE

================================= SAMPLE INPUT

======================================== SAMPLE OUTPUT