MATLAB: Impixelinfo how to get position of a selected point and the intensity in a variable

image processing

Hi, with impixelinfo you can see the values of intensity of different points in an image Pixel Info (X,Y): Intensity but how can you select a pixel from one image and get this info in the workspace?? (the position of the pixel and the intensity)

Best Answer

You'd have to call ginput() to get the value since impixelinfo() is not meant to operate in that way since it gives a "live" readout of wherever the user is.

[x, y] = ginput(1);
grayLevel = grayImage(y, x);  % Note x and y are switched since y = row.

Related Solutions

MATLAB: How to get value of all pixel in grayscale image

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];

MATLAB: Using impixelinfo command

Which Matlab version are you using? By 2008b at latest, the documentation for impixelinfo says,

IMPIXELINFO(H) creates a pixel information tool in the figure specified by the handle H, where H is an image, axes, uipanel, or figure object. Axes, uipanel, or figure objects must contain at least one image object.

Thus, the function would work for handles.axes2 because that axes contains an image.

To obtain coordinates within axes1 you may wish to activate datacursormode

Alternately, you may wish to set the figure WindowButtonMotionFcn property and have that callback function get() the figure CurrentPoint property and do whatever you need to do with it. If you only need the information upon clicks, use a WindowButtonDownFcn callback.

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Related Solutions

MATLAB: How to get value of all pixel in grayscale image

MATLAB: Using impixelinfo command

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