How to binarize a grayscale image with multiple thresholds?

I am trying to convert a grayscale image into a binary image with two thresholds:

• img = a grayscale image
• b = the output binary image
• if (img > t1) or (img < t2) then b = 1
• otherwise b = 0

t1 = 200;
t2 = 100;
src = imread('an rgb image');
img = reg2gray(src);
b1 = imbinarize(img, t1);
b2 = imbinarize(img, -t2);
b = imadd(b1,b2);

but this code doesn't work. Is there a function to set multiple thresholds at the same time?

Answer 1

[Akira Agata]

Assuming a grayscale image img is a 2D double array, the following code should work:

b = img > t1 | img < t2;