[Help me,please] How to crop image, remove background of currency ?

Don't use imcrop(image,[]);

after (i crop with photoshop ^^).

Use boundary, edge...
Please help me, thank you for watching.
I am a beginer, i hope an answers.
My english is bad. @@

[Jan]

At first: Are you sure this procedure is legal?

[Lee Bruce]

yes, im sure. this is my homework.

[Jan]

In Germany colored copies of banknotes and official documents like a driving license are forbidden the creation is a crime. When I try to scan money with the new printer/scanner unit, I get an error message and a message is sent to the manufacturer.

In a university course about differential equation we work with the professor on a solution of a larger problem. A colleague asked what the application of this formula is. In the next lesson the professor explained that it is used to improve the coating of a military stealth airplain. Well, this was legal also.

Sorry for these off-topic stories.

[Lee Bruce]

I'm sorry, I don't know about this.I was misleading. I'm so sorry. my subject is currency recognition using matlab. I have identified through the neural network but i don't remove background ...i just imcrop image with position. I use google translate.

[Jan]

@Lee Bruce: Everything is fine. I did not make the laws and I think they are not really smart. It is just a good idea to ask, before the forum assists you to get into troubles.

Let's trust your teacher.

[Lee Bruce]

^^

Answer 1

[Image Analyst]

This code will do it:

clc;    % Clear the command window.
% close all;  % Close all figures (except those of imtool.)
% clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;

%===============================================================================
% Read in a standard MATLAB color demo image.
folder = pwd;
baseFileName = 'bmbkK.jpg';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % Didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorChannels should be = 3.
[rows, columns, numberOfColorChannels] = size(rgbImage);
% Display the original color image.
subplot(2, 3, 1);
imshow(rgbImage);
title('Original Color Image', 'FontSize', fontSize, 'Interpreter', 'None');
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'Outerposition', [0, 0, 1, 1]);

hsvImage = rgb2hsv(rgbImage);
sImage = hsvImage(:, :, 2);
subplot(2, 3, 2);
imshow(sImage, []);
title('Saturation Image', 'FontSize', fontSize, 'Interpreter', 'None');

subplot(2, 3, 3);
histogram(sImage);
grid on;
title('Histogram of Saturation Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Threshold.
mask = sImage > 0.1;
% Extract biggest blob.
mask = bwareafilt(mask, 1);
% Fill holes.
mask = imfill(mask, 'holes');
subplot(2, 3, 4);
imshow(mask);
title('Mask Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Get bounding box.
props = regionprops(logical(mask), 'BoundingBox');
% Crop image.
croppedImage = imcrop(rgbImage, props.BoundingBox);
subplot(2, 3, 5);
imshow(croppedImage);
title('Cropped Image', 'FontSize', fontSize, 'Interpreter', 'None');

[Lee Bruce]

Thank you so much.I will try more. Wish the best things will come to you.^^

Answer 2

[Jan]

Do you have the Image Processing Toolbox and are you allowed to use it? You need a threshold at first to create a BW image. What about converting the RGB image to HSV colorspace, such that the grey/white pixels can be identified easily? Then a few pixels might be detected inside the banknote. which could be removed by a median filter. Finally regionprops with the 'BoundingBox' property might help. But you can search for the maximum and minimum rows and columns by find also.

Note that this forum does not post solutions of homework questions usually for good reasons. So try it and ask a specific question.

[Lee Bruce]

Yes i have Image Processing Toolbox but everything is automatic. I do on Guide.

In my country matlab is very strange.

There is no matlab training school and there is no book on matlab translation. I self study through youtube and google. I'm sorry, the image above I give on the internet .... I can not upload image to matlabwork because of many problems. ^^

[Jan]

You have a GUI already. What are the inputs for the question you ask here? The filename or the image data? What have you tried so far? Giving suggestions for improvements is much easier than guessing, what you exactly need. So please explain explicitely, how we can help you.

[Lee Bruce]

Thank you for everything. I found the answer.^^