Getting pixel values from an image

Hello, I am new to Matlab and I have a question concerning getting pixel values of an image. I have a 994x994 image and want to get every pixel value in the row 497. Could you please advise what command(s) I should use? Thank you very much.

I have loaded the image in Matlab with Imtool command and there is a pixel region window in which it shows all the pixel values I need. I am wondering if I could export them in an excel file? Thanks again.

Regards

Answer 1

[Thorsten]

If your image is stored in I, like from the command

 I = imread('peppers.png');

the Matlab syntax to select the element in row 497, column 1 would be

 x = I(497,1);

and the syntax to select all elements uses the column operator : as a shorthand for 1:end

 x = I(497, :);

[Gannian Zhang]

Thank you very much for your reply.

Could you please expand a little on your answer as I do not get what you say here? Thank you very much.

Regards

[Thorsten]

I've updated my response.

[Gannian Zhang]

Hi Thanks so much for the explanation. I have finally solved this problem. :-)

Answer 2

[Azzi Abdelmalek]

You can use imread to import your image like this

Im=imread('YourImage.tif')  % for example
row497=Im(497,:,:)

You can export your image to an excel file

xlswrite('file.xlsx',Im)

[Gannian Zhang]

Thank you very much for your reply.

I see. Now I get the idea. If I may, I wish to ask another quick question about using the 'imread' command. Here is what I did following your advice.

RGB = imread('image.tif');
I = rgb2gray(RGB);
Greyimage = imread(I); (But the command here did not work);

Also could you please tell me how I could do this:

row497 = Greyimage(497,i);

I wish to ask Matlab to export all the data from i=1 to i=997.

Thanks again for your kind help.

Regards

[Azzi Abdelmalek]

What is the aim of this: Greyimage = imread(I) ? I is not a file, it's already a matrix representing an image.

[Gannian Zhang]

Hi, thanks for your reply.

The original image was a coloured one which had three channels showing different pixel values. I wanted to convert it into a grey image first before analysis.

Could you please let me know how to do that? And how can I export data from i=1 to i=997 please? Regards.

[Gannian Zhang]

Hi Thank you for your help. I have finally solved the problem.