[Solved] ECE532 Homework 4- Histogram Thresholding

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; dont use existing thsholding-JVlated functions. Use

Kittler and Illingworths Kullback information minimization approach. You do not have to apply

the correction terms for tail truncation. Heres 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 Kittlers 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 dont submit that image.)

• Show the threshold value that Kittlers algorithm found for the address . png image.

Reference

1. Kittler and J. Illingworth, Minimum Error Thresholding, Pattern Recognition, vol. 19, no. 1,
2. 41-47, 1986.

Recursive Update Formulas

mul

varl =

mu2

var2 =

( q1p (varlprev+(mulprev mul) (mulprev-mul) )

(q2prev* (var2prev+(mu2prev -mu2) (mu2prev-mu2) )