how to get value of all pixel in grayscale image?

i have a grayscale image 80x80, how to get the value of pixel from that image?

Answer 1

[Image Analyst]

You specify the row and column:

grayImage = imread(filename);
% Find intensity at row 5, column 39:
thisIntensity = grayImage(5, 39);
% or
thisIntensity = impixel(grayImage, 5, 39);

You might also like to mouse around over the image and see a "live" interactive readout of the x, y, and intensity. If so, do this:

hp = impixelinfo();

You can then place it where like by doing

hp.Position = [x, y, width, height];

[Calvin Adi]

can i get all of the pixel in 1 time?

[Rik]

Yes, the values are inside the grayImage variable.

[Luis Fernandez]

he meant how to do it from all the pixels in the image all in one

[Image Analyst]

@Luis Fernandez. I have no idea what you said. All the pixels in the image are in one variable. If that's what you/he wants, there is nothing left to do since it is already like that.

To get the value of one single pixel, you can use row and column indexing

onePixelsValue = grayImage(row, column);

[Luis Fernandez]

I think he wants to get a table with columns [X Y Grayscale] so he can look at every single pixel with its grayscale value.

[Image Analyst]

@Luis Fernandez, well that would be a most inefficient way of doing it. But you can create a table if you want

grayImage = imread('cameraman.tif');
[rows, columns, numberOfColorChannels] = size(grayImage)
if numberOfColorChannels == 3
	grayImage = rgb2gray(grayImage);
end

% Resize to 5x5 to make the image and table smaller for demo purposes.
% grayImage = imresize(grayImage, [5, 5]);
% [rows, columns, numberOfColorChannels] = size(grayImage)

% Get list of all rows and columns.
[r, c] = meshgrid(1:rows, 1:columns); % or [y, x] instead of [r, c]
t = table(c(:), r(:), grayImage(:), 'VariableNames', {'RowNumber', 'Column', 'GrayLevel'})

or you can just create a 2-D double array instead of a table:

xyGL = [c(:), r(:), double(grayImage(:))] % Each row is x, y, gray level.  c = column = x

[Ankita Mukund Mandale]

Thanks its working. But I want to plot grayvalues and pixel. From that graph I want to get gaussian curve. Could you help me with it ?

[Image Analyst]

Sure. Did you use the plot() function? And what do you think the difference is between "grayvalues" and "pixel"??? The value of a pixel is its gray level. And the gray levels are what they are, and they may not be the Gaussian curve you're expecting.