algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::Features2dGreySignaturePtr	ipsdk::imaproc::registration::extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipUInt32 inNbFeatures)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::Features2dGreySignaturePtr	ipsdk::imaproc::registration::extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipReal32 inGradStdDev, const ipUInt32 inNbFeatures, const ipUInt32 inFeaturesDist)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::Features2dGreySignaturePtr	ipsdk::imaproc::registration::extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipReal32 inGradStdDev, const attr::GaussianCoverageConstPtr &pInOptGradientGaussianCoverage, const ipsdk::imaproc::attr::CornerDetectionParamsConstPtr &pInCornerDetectionParams, const ipUInt32 inNbFeatures, const ipUInt32 inFeaturesDistX, const ipUInt32 inFeaturesDistY, const ipsdk::imaproc::attr::eInterpolationPolicy &inInterpolationPolicy, const ipsdk::imaproc::attr::SamplingBallInfoConstPtr &pInSamplingBallInfo2d)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::PlanIndexedFeatures2dGreySignaturePtr	ipsdk::imaproc::registration::multiSlice_extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipUInt32 inNbFeatures)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::PlanIndexedFeatures2dGreySignaturePtr	ipsdk::imaproc::registration::multiSlice_extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipReal32 inGradStdDev, const ipUInt32 inNbFeatures, const ipUInt32 inFeaturesDist)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

IPSDKIPLREGISTRATION_API attr::PlanIndexedFeatures2dGreySignaturePtr	ipsdk::imaproc::registration::multiSlice_extractGreySignedFeatures2d (const image::ImageConstPtr &pInImg, const ipReal32 inGradStdDev, const attr::GaussianCoverageConstPtr &pInOptGradientGaussianCoverage, const attr::CornerDetectionParamsConstPtr &pInCornerDetectionParams, const ipUInt32 inNbFeatures, const ipUInt32 inFeaturesDistX, const ipUInt32 inFeaturesDistY, const attr::eInterpolationPolicy &inInterpolationPolicy, const attr::SamplingBallInfoConstPtr &pInSamplingBallInfo2d)
	wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image More...

Detailed Description

algorithm allowing to extract 2d features associated to a grey signature from an image

This algorithm combines a feature detector algorithm (see Harris corner detection 2d) with a grey level feature signature algorithm allowing description of neighborhood of detected points.

Feature detector is controlled by following parameters : $InOptGradStdDev$ , $InOptGradientGaussianCoverage$ , $InOptCornerDetectionParams2d$ , $InNbFeatures$ , $InOptFeaturesDistX$ and $InOptFeaturesDistY$ . See Harris corner detection 2d for more informations on these parameters.

Local feature signature is computed using a "sampling ball" which is composed of rings centered at feature point. Each ring is associated to a radius, to a blurring factor (we sample blurred versions of input image $InImg$ using Gaussian Smoothing 2d algorithm) and to a number of samples regularly dispatched around sampling ring. Angle of first sample $\overrightarrow{V}$ is defined using orientation of inertia tensor main direction. Note that blurr factor usually increase with sampling ring radius.

Sampling ball can be customized via parameter $InOptSamplingBallInfo2d$ . All extracted values are stacked into a single "by plane" data collection $OutPIGreySignatures2d$ .

Parameter $InOptInterpolationPolicy$ allows to specify an interpolation policy used during signature sampling.

An optional scale factor $InOptSignatureScaleFactor$ allows to generate comparable feature signatures for images with different scale factors (results of this algorithm are not scale invariant).

This algorithm is based on an adaptation of following work :

Nicolas Allezard, Michel Dhome, Frederic Jurie. Mise en correspondance multi-echelle. 17ieme Colloque sur le Traitement du Signal et des Images, Sep 1999, Vannes, France. Groupe d'Etudes du Traitement du Signal et des Images (GRETSI), pp.897–900, 1999.

See also: https://en.wikipedia.org/wiki/Feature_detection_(computer_vision)

Attributes description

Attribute description for algorithm :

Name	ToolTip	Default Initializer
ipsdk::imaproc::attr::InImg	[Input] image for processing operation	X
ipsdk::imaproc::attr::InOptSignatureScaleFactor	[Input Optional] image scale factor used during signature computation	X
ipsdk::imaproc::attr::InOptGradStdDev	[Input Optional] standard deviation used for gradient computation	X
ipsdk::imaproc::attr::InOptGradientGaussianCoverage	[Input Optional] Parameter allowing to specify a gaussian distribution coverage for processing	X
ipsdk::imaproc::attr::InOptCornerDetectionParams2d	[Input Optional] parameters used during corner detection process	X
ipsdk::imaproc::attr::InNbFeatures	[Input] target number of features to be detected by algorithm	X
ipsdk::imaproc::attr::InOptFeaturesDistX	[Input Optional] distance between detected features along x axis (tchebychev distance)	X
ipsdk::imaproc::attr::InOptFeaturesDistY	[Input Optional] distance between detected features along y axis (tchebychev distance)	X
ipsdk::imaproc::attr::InOptInterpolationPolicy	[Input Optional] interpolation policy used to extract local data from image	X
ipsdk::imaproc::attr::InOptSamplingBallInfo2d	[Input Optional] Parameters for used sampling ball around image points	X
ipsdk::imaproc::attr::OutWk1Img	[Output] Temporary working image for algorithm	promoteUnary (_pOutWk1Img, _pInImg, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutWk2Img	[Output] Temporary working image for algorithm	promoteUnary (_pOutWk2Img, _pInImg, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutWk3Img	[Output] Temporary working image for algorithm	promoteUnary (_pOutWk3Img, _pInImg, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutWk4Img	[Output] Temporary working image for algorithm	promoteUnary (_pOutWk4Img, _pInImg, ipsdk::imaproc::ePromoteUnaryType::ePUT_UpperSigned)
ipsdk::imaproc::attr::OutPIGreySignatures2d	[Output] collection of features 2d grey signature used during processing	fromImage (_pOutPIGreySignatures2d, _pInImg)

Global Rule description

Global rule description for algorithm :
ipsdk::imaproc::matchSize (_pOutWk1Img,_pInImg) &&
ipsdk::imaproc::matchSizeAndType (_pOutWk1Img,_pOutWk2Img,_pOutWk3Img) &&
ipsdk::imaproc::matchImagePlans (_pOutPIGreySignatures2d,_pInImg)

Example of Python code :

Example imports

import PyIPSDK

import PyIPSDK.IPSDKIPLRegistration as registration

Code Example

    # opening of input image
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    nbFeatures = 100
    
    # extraction of grey signed features from image
    outGreySignatures1 = registration.extractGreySignedFeatures2d(inImg, nbFeatures)
    print("First feature found at {x=" + str(outGreySignatures1.signatureColl[0].x) +
                                ", y=" + str(outGreySignatures1.signatureColl[0].y) + "}")

Example of C++ code :

Example informations

Associated library

IPSDKIPLRegistration

Header file

#include <IPSDKIPL/IPSDKIPLRegistration/Processor/ExtractGreySignedFeatures2d/ExtractGreySignedFeatures2d.h>

Code Example

    // Load the input image
    ImagePtr pInImg = loadTiffImageFile(inImgFilePath);
    // extraction of grey signed features from image
    Features2dGreySignaturePtr pOutGreySignatures1 = extractGreySignedFeatures2d(pInImg, 100);

See also: ExtractGreySignedFeatures2dLvl1; ExtractGreySignedFeatures2dLvl2

Function Documentation

◆ extractGreySignedFeatures2d() [1/3]

IPSDKIPLREGISTRATION_API attr::Features2dGreySignaturePtr ipsdk::imaproc::registration::extractGreySignedFeatures2d	(	const image::ImageConstPtr &	pInImg,
		const ipUInt32	inNbFeatures
	)

wrapper function for algorithm allowing to extract 2d features associated to a grey signature from an image

Note: These wrappers must be used with mono slice (sizeZ=sizeC=sizeT=1) input images

Exceptions