finding the exact thrreshold for im2bw

Hello to everyone, i'm trying to convert an image to logical,so i have to find a threshold for im2bw, but i don't know which is the right algorithm to do this?

Answer 1

[Walter Roberson]

There is no one algorithm: it depends on what you are interested in examining.

You might want to look at graythresh()

[Mary Kodogianni]

I want to convert an image with gaussian spots to binary and find the coordinates of the gaussians but i don't know wich threshold to use..

Answer 2

[Image Analyst]

You might be interested in a visual/interactive GUI to allow you to pick a threshold: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Answer 3

[Sean de Wolski]

It is calculated from the range of the class(im)

range = getrangefromclass(A);
BWp = (A > range(2) *level);

Is the engine: So for example:

range = getrangefromclass(uint8(magic(3)));
level = 0.75;
range(2) *level
ans =

       191.25

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