slicing image by histogram

Hi I have image of connected text I was trying to use histogram vlues to segment it/slice it. Basicaly im=imread('test.jpg') 1. take histogram of the test image 2. slice/segment the image wherever the value of histogram is below certain number what would be the best way to do that? thanks

Answer 1

[Image Analyst]

See my BlobsDemo tutorial on this topic:

http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Basically

binaryImage = grayImage >= lowThreshold & grayImage <= HighThreshold;
labeledImage = bwlabel(binaryImage);
measurements = regionprops(labeledImage, 'all');

You supply values for lowThreshold and highThreshold of course.

Answer 2

[Tarik Razak]

when i read grayImage=imread('image.jpg') and use the above code i get the error ??? Undefined function or method 'regionpropos' for input arguments of type 'double'.

Did i read it in wrong format? thanks

[Image Analyst]

regionpropos() is not a function. Try regionprops() like I suggested. ALso make sure your image is grayscale:

[rows columns numberOfColorChannels] = size(grayImage);

if numberOfColorChannels > 1

grayImage = grayImage(:,:,2); % Take green channel only

% grayImage = rgb2gray(grayImage); % Alternative, weighted average of RG&B

end