how to calculate the area of certain portion of an image ?

how to calculate the area of certain portion of an image ?

Answer 1

[Image Analyst]

Call regionprops(). See my Image Segmentation Tutorial. It goes over all of that:

BlobsDemo

For example with a simple thresholding:

binaryImage = grayImage > 90;
measurements = regionprops(binaryImage, 'Area');
allAreas = [measurements.Area];

[ajay]

its ok but i want the area of particular area

[Image Analyst]

Then just get it. For example to get the area of blob #42, do this

blob42area = allAreas(42);
blob42area = measurements(42).Area; % Same thing as above.