Description
Write a computer program to threshold a grayscale image to obtain a bi-level image. Write your
own code for the steps of the algorithm; don’t use existing thæsholding-JVlated functions. Use
Kittler and Illingworth’s Kullback information minimization approach. You do not have to apply
the correction terms for tail truncation. Here’s a possible command-line user interface:
USAGE
thresh I-t T] infile outfile
T: user-specified threshold; € T 255;
default: T is automatically computed using Kittler’s method
infile: the input grayscale image
outfile: the output bi-level image
DESCRIPTION
If a fixed threshold is not specified, then it is automatically
computed by minimizing the Kullback information measure .
Specifically, the image is thresholded as follows:
= 255 if X[n] T
= if x [n] < T
Submit the following items:
- Your commented source code files.
Run your program on the address . png image, and submit the thresholded image.
(You should also try your program on graybook . png, but don’t submit that image.)
- Show the threshold value that Kittler’s algorithm found for the address . png image.
Reference
- Kittler and J. Illingworth, “Minimum Error Thresholding,” Pattern Recognition, vol. 19, no. 1,
- 41-47, 1986.
Recursive Update Formulas
mul
varl =
mu2
var2 =
( q1p (varlprev+(mulprev – mul) (mulprev-mul) )
(q2prev* (var2prev+(mu2prev -mu2) (mu2prev-mu2) )
