houghLine

Name

houghLine - Hough transform for line detection

Syntax

 houghLine [<option>...] <inimage>

Description

Performs a Hough transform to detect lines. Every band in the input image inimage is transformed to a two dimensional Hough space, a (theta, rho) space.

After creating the transform, the Hough space may be searched for local maxima. Within each band, only the largest local maximum (maxima) within a wsxws area is registered. Besides, only maxima with number of updates above a limit given by the -ul option are used. A list of these maxima may be written to stdout, depending on the options given.

Options

-list

Print a list of maxima to stdout. Default: Don't.

-tf transformFileName

Save the transform to transformFileName. Default: Don't save.

-rf reconstructionFileName

The Hough-space maxima are used to reconstruct the image, and the image is written to reconstructionFileName. Default: Don't reconstruct and save.

-tt transformTitle

Use transformTitle as title for transformed image. Default: "Hough Line Transform".

-rt reconstructionTitle

Use reconstructionTitle as title for reconstructed image. Default: "Hough Line Reconstruction".

-ul updateLimit

This determines the minimum number of updates for a maximum to be used. The minimum number is determined from updateLimit and the size of the hough space image:

 updateLimit * MAX(horizontal size, vertical size)

Default: 0.1.

-ws windowSize

Default: 7.

Restrictions

inimage must have bands with pixel type unsigned byte.

Author

Tor Lønnestad, BLAB, Ifi, UiO

Examples

 houghLine -tf monaHT.img -rf monaRF.img -ul 0.2 mona.img

Id

$Id: houghLine.c,v 1.30 1997/03/07 12:52:01 svein Exp $