MATLAB: I want to know the pixel intensity value in an image but it gives different results using data cursor and command.which one is correct? and why it is showing differently

image intensityImage Processing Toolbox

let A is image

i want to know intensity value at (25,170).so by using command A(25,170) we can find intensity value but,using data cursor it shows different intensity value

Best Answer

Impixelinfo is reporting in x,y convention. You are indexing in row,col. Index A(y,x) and this should resolve the issue.

Related Solutions

MATLAB: How to find the index of xy coordinate in an image

Try this:

value = binaryImage(y, x);  % Note -- it's NOT (x,y).

MATLAB: When i plot a grayscale image and check the value of a pixel using data cursor, it shows me the values between 0 and 1 which looks reasonable but it has a RGB scale. Can a grayscale image has RGB Values

Hi Anvinder,

The Data Cursor displays color values as they are displayed, rather than as the image data is stored. So for a grayscale image, or even binary image, RGB values will still be displayed, because that is how the color is actually shown. In both of those cases, though, all three of the red, green, and blue values should be the same.

This is similar to why the RGB values may differ from the index value in a grayscale image. For example:

I = 0.5*ones(100);
imshow(I)

If you put a data cursor anywhere, the index will be 0.5, but the RGB values will all be 0.502. This is because 0.502 is the closest value to that index in the colormap used for the display of the colors.

In short, RGB values are expected to be displayed. If you want to know what grayscale intensity value is being displayed in that pixel, use any of the RGB values. If you want to know what data is in the original image (fed to "imshow"), use the index value.

-Cam

Best Answer

Related Solutions

MATLAB: How to find the index of xy coordinate in an image

MATLAB: When i plot a grayscale image and check the value of a pixel using data cursor, it shows me the values between 0 and 1 which looks reasonable but it has a RGB scale. Can a grayscale image has RGB Values

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