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gevd_noise Class Reference

#include <gevd_noise.h>

List of all members.

Detailed Description

Definition at line 33 of file gevd_noise.h.

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

Friends

class DetectionUI

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 78 of file gevd_noise.cxx.

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 89 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 171 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 269 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 216 of file gevd_noise.cxx.

Friends And Related Function Documentation

friend class DetectionUI [friend]
 

Definition at line 36 of file gevd_noise.h.

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.

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