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fl::DescriptorSIFT Class Reference

#include <descriptor.h>

Inheritance diagram for fl::DescriptorSIFT:

List of all members.

Public Methods
	DescriptorSIFT (int width=4, int angles=8)
	DescriptorSIFT (std::istream &stream)
void	computeGradient (const Image &image)
virtual Vector< float >	value (const Image &image, const PointAffine &point)
	Returns a vector of floats that describe the image patch near the interest point.
virtual Image	patch (const Vector< float > &value)
	Return a graphical representation of the descriptor. Preferrably an image patch that would stimulate this descriptor to return the given value.
void	patch (const std::string &fileName, const Vector< float > &value)
	Write a visualization of the descriptor to a postscript file.
void	patch (Canvas *canvas, const Vector< float > &value, int size)
	Subroutine used by other patch() methods.
virtual Comparison *	comparison ()
	Return a MetricEuclidean, rather than the default (NormalizedCorrelation).
virtual void	read (std::istream &stream)
virtual void	write (std::ostream &stream, bool withName=true)
Public Attributes
int	width
	Number of horizontal or vertical positions.
int	angles
	Number of orientation bins.
int	supportPixel
	Pixel radius of normalized form of affine-invariant patch, if used.
float	sigmaWeight
	Size of Gaussian that weights the entries in the bins.
float	maxValue
	Largest permissible entry in one bin.
void *	lastBuffer
	For detecting change in cached image.
double	lastTime
	For detecting change in cached image.
ImageOf< float >	I_x
	x component of gradient vectors
ImageOf< float >	I_y
	y component of gradient vectors

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Detailed Description

Implements David Lowe's SIFT descriptor. Note on supportRadial: supportRadial * point.scale gives pixel distance from center to edge of bins when they overlay the image. The pixel diameter of one bin is 2 * supportRadial * point.scale / width.

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Constructor & Destructor Documentation

DescriptorSIFT::DescriptorSIFT (  int    width = 4, int    angles = 8 )

DescriptorSIFT::DescriptorSIFT (  std::istream &    stream )

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Member Function Documentation

Comparison * DescriptorSIFT::comparison (    )  [virtual]

Return a MetricEuclidean, rather than the default (NormalizedCorrelation). Reimplemented from fl::Descriptor.

void DescriptorSIFT::computeGradient (  const Image &    image )

void DescriptorSIFT::patch (  Canvas *    canvas, const Vector< float > &    value, int    size )  [inline]

Subroutine used by other patch() methods.

void DescriptorSIFT::patch (  const std::string &    fileName, const Vector< float > &    value )

Write a visualization of the descriptor to a postscript file.

Image DescriptorSIFT::patch (  const Vector< float > &    value )  [virtual]

Return a graphical representation of the descriptor. Preferrably an image patch that would stimulate this descriptor to return the given value. Implements fl::Descriptor.

void DescriptorSIFT::read (  std::istream &    stream )  [virtual]

Reimplemented from fl::Descriptor.

Vector< float > DescriptorSIFT::value (  const Image &    image, const PointAffine &    point )  [virtual]

Returns a vector of floats that describe the image patch near the interest point. Implements fl::Descriptor.

void DescriptorSIFT::write (  std::ostream &    stream, bool    withName = true )  [virtual]

Reimplemented from fl::Descriptor.

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Member Data Documentation

int fl::DescriptorSIFT::angles

Number of orientation bins.

ImageOf<float> fl::DescriptorSIFT::I_x

x component of gradient vectors

ImageOf<float> fl::DescriptorSIFT::I_y

y component of gradient vectors

void* fl::DescriptorSIFT::lastBuffer

For detecting change in cached image.

double fl::DescriptorSIFT::lastTime

For detecting change in cached image.

float fl::DescriptorSIFT::maxValue

Largest permissible entry in one bin.

float fl::DescriptorSIFT::sigmaWeight

Size of Gaussian that weights the entries in the bins.

int fl::DescriptorSIFT::supportPixel

Pixel radius of normalized form of affine-invariant patch, if used.

int fl::DescriptorSIFT::width

Number of horizontal or vertical positions.

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

• descriptor.h
• DescriptorSIFT.cc

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