taking part of the picture

 Hi;
I'm newbie in mat lab and I've a picture that I need to cut or delete the bottom region of it and I've used this cod it makes error I do not know why and how can i take a portion of this picture and not all of it.
Here is the code:

ROI= imread('pic.jpg');

imfinfo('pic.jpg');%to know the number of columns and number of rows

nRows=1180;

nColumns=2039;

%Region Of Interest exclude the bottom part

% ROI=imresize(ROI,[nRows nColumns]);

ROI=ROI(1:1180,:);

imshow('pic.pg')

Thanks in advance

Answer 1

[Harshit]

Here is an error you can't use imshow on an image. You have to first read it in a variable then use imshow on that. imshow(ROI) is the correct answer

[eman]

Thanks for your reply,it works well,but the picture has been repeated for three times I don't know why and the bottom part still as it was, it should be excluded.

thanks in advance

[Image Analyst]

Harshit's answer is not correct - you should not have accepted it. You can pass in a string with a filename in it into imshow and it will read the file and display it. And I don't understand what you are saying in your comment.

[Harshit]

Sorry I agree image analyst point is correct.

[eman]

Thanks Image Analyst,Thanks Harshit I have accepted Harshit answer because when I changed the code from

imshow('pic.jpg') TO

imshow(ROI)

a figure has showed up

about what I'm saying my comment,I need to take a portion from the picture not whole the picture then I am going to use sobel edge detection. when the program ran it showed a figure with 3 copies of the original picture.

I hope that I clarify my problem.

Thanks again ,I hope you can help me.

Answer 2

[Image Analyst]

You need to show your ROI variable, not some bad filename. You put pic.pg, not pic.jpg, so that doesn't exist, but anyway, even if a file by that name existed, that will display the full file, not a cropped portion of it. You should do it this way:

grayImage = imread('pic.jpg');
croppedImage = grayImage(1:1180, :);
imshow(croppedImage);

[eman]

Thanks Image Analyst,

I have tried your suggested code but the same thing happen the image didn't crop and the image repeated itself in the output figure.

what can I do?

Thanks in advance

[Image Analyst]

I find that hard to believe. Here, run this demo and see if it works:

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

% Read in a standard MATLAB gray scale demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
baseFileName = 'concordorthophoto.png';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
  % File doesn't exist -- 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 in the search path folders.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
grayImage = imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows columns numberOfColorBands] = size(grayImage)
% Display the original gray scale image.
subplot(1, 2, 1);
imshow(grayImage, []);
title('Original Grayscale Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Give a name to the title bar.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off') 

% Crop off the first 1180 lines and display that:
croppedImage = grayImage(1:1180, :);
[rows2 columns2 numberOfColorBands2] = size(croppedImage)
subplot(1, 2, 2);
imshow(croppedImage, []);
title('Cropped Grayscale Image', 'FontSize', fontSize);

[eman]

Thanks too much it works will.