thresMinErrIter
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Name
thresMinErrIter - minimum error threshold, iteration method
Syntax
#include <xite/threshold.h>
int thresMinErrIter( histogram h, int tinit );
Description
thresMinErrIter calculates the threshold value by using
the minimum error thresholding technique as in Kittler &
Illingworth (2nd method) and Gonzalez & Wintz.
Initially, the threshold value t is set according to tinit.
0 <= tinit <= 255, then t = tinit
tinit = -1, then t = the average of all the pixels
tinit = -2, then t = the result from thresRidCal(h)
Iteratively, the new threshold is found by solving the equation
(7.3-13) in Gonzalez & Wintz.
The variances and the means are the variances and means above
and belov the treshold. When the threshold value
remains constant, iteration terminates.
The actual thresholding is not performed, see the
routine "threshold".
Reference
J. Kittler & J. Illingworth: "Minimum Error Thresholding"
Pattern Recognition, Vol 19, nr 1. 1986, pp. 41-47.
Gonzales, Rafael C & Wintz, Paul:
"Digital Image Processing"
Addison-Wesley, 1977.
Q.-Z. Ye & P.-E. Danielsson:
"On Minimum Error Thresholding and Its Implementations"
Pattern Recognition Letters 7,
1988, pp. 201-206.
Return value
The threshold value. Pixel values up to, and including,
the return value, is below the threshold.
Author
Olav Borgli, BLAB, ifi, UiO
Id
$Id: thresMinErr.c,v 1.25 1997/03/17 13:45:07 svein Exp $