What is Image Thresholding?
Thresholding is the technique of generating a binary image (a binary image is one whose pixels have only two values – 0 and 1 and thus require only one bit to store pixel intensity) from a given greyscale image by separating it into two regions based on a threshold value. Hence pixels having intensity values greater than the said threshold will be treated as white or 1 in the output image and the others will be black or 0.
In other words, if we have a threshold T, then the segmented image g(x,y) is computed as shown below:
g(x,y) = 1 if f(x,y) > T and g(x,y) = 0 if f(x,y) ≤ T.
So the output segmented image has only two classes of pixels – one having a value of 1 and others having a value of 0.
Optimum Global Thresholding Using Otsu’s Method
Image thresholding is one of the segmentation techniques, that segments or divided the image into two or more different parts based on pixel intensities. There are many different algorithms for carrying out thresholding and here we are going to see one of the most efficient and optimum techniques called Otsu’s method.