gevd_noise Class Reference

#include <gevd_noise.h>

List of all members.

Public Member Functions
	gevd_noise (const float *data, const int n, const int number_of_bins=200)
	Generate the histogram curve at low responses to estimate the sensor/texture noise in data.
	~gevd_noise ()
	Free allocated space.
bool	EstimateSensorTexture (float &sensor, float &texture) const
	Fit a Raleigh distribution to the histogram curve of edgels with low magnitudes, h(x), to estimate the sensor noise, as would be zero-crossing of dh(x), and texture noise as the dominant peak in h(x).
const float *	Histogram (int &n) const
float	BinSize () const
Static Public Member Functions
static float *	EdgelsInCenteredROI (const gevd_bufferxy &magnitude, const gevd_bufferxy &dirx, const gevd_bufferxy &diry, int &nedgel, const int roiArea=250 *250)
	Collect all edgels above zero, in an ROI at center of image.
Static Protected Member Functions
static bool	WouldBeZeroCrossing (const float *dhist, const int nbin, float &index)
	Find would be zero-crossing of the derivative of the histogram from its downward curvature.
static bool	RealZeroCrossing (const float *dhist, const int nbin, float &index)
	Find real zero-crossing of the derivative of the histogram.
Protected Attributes
float *	hist
int	nbin
float	binsize
Private Member Functions
	gevd_noise ()
Friends
class	DetectionUI

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Detailed Description

Definition at line 33 of file gevd_noise.h.

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Constructor & Destructor Documentation

gevd_noise::gevd_noise	(	const float *	data,
		const int	n,
		const int	number_of_bins = 200
	)

Generate the histogram curve at low responses to estimate the sensor/texture noise in data.

Definition at line 15 of file gevd_noise.cxx.

gevd_noise::~gevd_noise

(

)

Free allocated space.

Definition at line 79 of file gevd_noise.cxx.

gevd_noise::gevd_noise

(

)

[inline, private]

Definition at line 63 of file gevd_noise.h.

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Member Function Documentation

float gevd_noise::BinSize

(

)

const [inline]

Definition at line 50 of file gevd_noise.h.

float * gevd_noise::EdgelsInCenteredROI	(	const gevd_bufferxy &	magnitude,
		const gevd_bufferxy &	dirx,
		const gevd_bufferxy &	diry,
		int &	nedgel,
		const int	roiArea = 250*250
	)		[static]

Collect all edgels above zero, in an ROI at center of image.

This utility function is used to collect edgels from a response image, i.e. gradient/hessian/laplacian, or other edge response image.

Definition at line 90 of file gevd_noise.cxx.

bool gevd_noise::EstimateSensorTexture	(	float &	sensor,
		float &	texture
	)		const

Fit a Raleigh distribution to the histogram curve of edgels with low magnitudes, h(x), to estimate the sensor noise, as would be zero-crossing of dh(x), and texture noise as the dominant peak in h(x).

Setting the threshold at 3 times the sensor/texture noise would eliminate 99% of all noisy edges. The raw noise in the original image can be deduced from the filter used to convolve with the image. H. Voorhees & T. Poggio, Detecting Blobs as Textons in Natural Images, Proc. 1987 IU Workshop, Los Angeles, CA.

Definition at line 174 of file gevd_noise.cxx.

const float* gevd_noise::Histogram

(

int &

n

)

const [inline]

Definition at line 49 of file gevd_noise.h.

bool gevd_noise::RealZeroCrossing	(	const float *	dhist,
		const int	nbin,
		float &	index
	)		[static, protected]

Find real zero-crossing of the derivative of the histogram.

This is texture noise in the ROI. Protected.

Definition at line 272 of file gevd_noise.cxx.

bool gevd_noise::WouldBeZeroCrossing	(	const float *	dhist,
		const int	nbin,
		float &	index
	)		[static, protected]

Find would be zero-crossing of the derivative of the histogram from its downward curvature.

This is sensor noise in the ROI. Protected.

Definition at line 219 of file gevd_noise.cxx.

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Friends And Related Function Documentation

friend class DetectionUI [friend]

Definition at line 36 of file gevd_noise.h.

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Member Data Documentation

float gevd_noise::binsize [protected]

Definition at line 55 of file gevd_noise.h.

float* gevd_noise::hist [protected]

Definition at line 53 of file gevd_noise.h.

int gevd_noise::nbin [protected]

Definition at line 54 of file gevd_noise.h.

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The documentation for this class was generated from the following files:

• contrib/gel/gevd/gevd_noise.h
• contrib/gel/gevd/gevd_noise.cxx