w2img::Watershed Class Reference

List of all members.

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Detailed Description

Segments a weather-type image using the watershed algorithm.

Author:

: Lakshman

Version:

:

Id

w2img_Watershed.h,v 1.3 2009/06/02 20:17:56 lakshman Exp

Public Member Functions
	Watershed (int marker_min, int marker_max)
	To create a Watershed object to use to segment.
code::Image< int >	vincent_segment (const code::Image< int > &img, bool only_dividing_lines=false) const
	Segment the image.
code::Image< int >	vincent_segment2 (const code::Image< int > &img, bool only_dividing_lines=false) const
	The Vincent/Soille Algorithm with some of the operations re-ordered for clarity.
code::Image< int >	heir_segment (const code::Image< int > &img, int thresh, int dist_thresh) const
	Returns a heirarchially labeled image.
code::Image< int >	najman_segment (const code::Image< int > &img) const
	The Najman/Schmitt Algorithm with some of the operations re-ordered for clarity.
Static Public Attributes
static const int	WSHED
Protected Member Functions
bool	is_valid (int val) const
	is the given value within bounds?
bool	is_valid (code::Image< int > img, int x, int y) const
	Helper function to test whether pixel x,y contains a valid value.
Static Protected Member Functions
static bool	within_thresh (const Pixel &p, const code::Image< int > &level, int dist_thresh)
	Helper function to find out whether the Hamming distance of the pixel from a level lower than it is < dist_thresh.
Classes
class	Pixel
class	RegionInfo

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Constructor & Destructor Documentation

w2img::Watershed::Watershed	(	int	marker_min,
		int	marker_max
	)

To create a Watershed object to use to segment.

Parameters:

	marker_min	: the lowest "valid" value for a storm. This has to be greater than zero; if valid values can be negative, scale the data.
	marker_max	: the highest "valid" value for a storm.

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Member Function Documentation

code::Image<int> w2img::Watershed::heir_segment	(	const code::Image< int > &	img,
		int	thresh,
		int	dist_thresh
	)			const

Returns a heirarchially labeled image.

Label 1 is the lowest and higher labels contain lower labels.

The watersheds are the Vincent-Soille dividing lines, so the heirarchial labels have no relation to the watershed dividing lines.

bool w2img::Watershed::is_valid	(	code::Image< int >	img,
		int	x,
		int	y
	)			const [inline, protected]

Helper function to test whether pixel x,y contains a valid value.

x,y need not be inside the image (bounds are tested)

bool w2img::Watershed::is_valid

(

int

val

)

const [inline, protected]

is the given value within bounds?

code::Image<int> w2img::Watershed::najman_segment

(

const code::Image< int > &

img

)

const

The Najman/Schmitt Algorithm with some of the operations re-ordered for clarity.

The result is identical to the original.

With optimization -O5 on g++, there is no performance cost: it takes 3 usec of CPU time to process a 1000x1000 image using either method.

code::Image<int> w2img::Watershed::vincent_segment	(	const code::Image< int > &	img,
		bool	only_dividing_lines = false
	)			const

Segment the image.

(Vincent/Soille Algorithm) . If only_dividing_lines is set to true, then only those are retained in the resulting image. Ordinarily, the completely labeled image is returned.

Source: Luc Vincent and Pierre Soille, Watersheds in Digital Spaces, IEEE Transactions on Pattern Analysis and Machine Intelligence, June 1991.

code::Image<int> w2img::Watershed::vincent_segment2	(	const code::Image< int > &	img,
		bool	only_dividing_lines = false
	)			const

The Vincent/Soille Algorithm with some of the operations re-ordered for clarity.

The result is identical to the original.

With optimization -O5 on g++, there is no performance cost: it takes 3 usec of CPU time to process a 1000x1000 image using either method.

static bool w2img::Watershed::within_thresh	(	const Pixel &	p,
		const code::Image< int > &	level,
		int	dist_thresh
	)			[static, protected]

Helper function to find out whether the Hamming distance of the pixel from a level lower than it is < dist_thresh.

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Member Data Documentation

const int w2img::Watershed::WSHED [static]

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