thresBernsen

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Name

thresBernsen - local variable treshold by the method of Bernsen.

Syntax

thresBernsen [<option>...] <infile> <outfile> cmin [dx [dy]]

Description

Local variable treshold by the method of Bernsen.

cmin: Local contrast treshold.
dx: Local window width, default 3.
dy: Local window height, default dx.

Options

-lpv lpv: Low pixel value, default 0.
-hpv hpv: High pixel value, default 255.
-low: Homogenous areas are assumed to be low, below the threshold. Default: above the threshold

If the difference between the largest and the smallest pixel value within the dx*dy window is greater than or equal to cmin, the average of the two values is used as threshold. Pixels below this threshold are set to lpv, and pixels above are set to hpv.

If -low is set, pixels in homogenous areas (difference below cmin) are assumed to be below the threshold and are set to lpv, otherwise these pixels are set to hpv.

Reference

Bernsen, J: "Dynamic thresholding of grey-level images" Proc. of the 8th ICPR, Paris, Oct 1986, 1251-1255.

Example

 thresBernsen mona.img monat.img 100
 thresBernsen -lpv 1 -hpv 0 mona.img monat.img 75 35 55

Author

Olav Borgli and Tor L|nnestad

Id

$Id: thresBernsen.c,v 1.22 1997/01/14 13:10:39 svein Exp $