houghCircle

Name

houghCircle, houghCircles - Hough transform for circle detection

Syntax

 #include <xite/hough.h>

 BiffStatus houghCircle( IBAND input,
    IUS_BAND output, int radius );

 BiffStatus houghCircles( IBAND input,
    IUS_IMAGE output, int rmin, int rmax );

Description

Performs a Hough transform to detect circles.

houghCircle transforms the input band input to Hough space, output, looking at circles with radius only. The input band should be something like a thresholded edge image. All pixels larger than 0 are transformed to Hough space.

houghCircles transforms for all radii between rmin and rmax. First band of output will correspond to radius rmin, second band to radius rmin+1 and so on. output should thus have a number of bands at least equal to rmax - rmin + 1.

Notice that output band(s) are of type unsigned short to avoid overflow in accumulation.

Restrictions

input must have pixel type unsigned byte.

Return value

 0 - OK
 1 - bad input pixel type
 2 - bad output pixel type
 3 - bad radius value
 4 - not enough bands

Author

Tor Lønnestad, BLAB, Ifi, UiO

Id

$Id: houghCircle.c,v 1.33 1997/01/10 16:02:06 svein Exp $