Package boofcv.alg.geo.trifocal

Class TrifocalExtractGeometries

java.lang.Object

boofcv.alg.geo.trifocal.TrifocalExtractGeometries

public class TrifocalExtractGeometries
extends Object

Extracts the epipoles, camera matrices, and fundamental matrices for views 2 and 3 with respect to view 1 from the trifocal tensor. Epipoles are found in homogeneous coordinates. Singular value decomposition is used to compute each vector and is robust to noise and epipoles will have a norm of one..

Properties:

• e2^T*F12 = 0
• e3^T*F13 = 0

where F1i is a fundamental matrix from image 1 to i.

References:

• R. Hartley, and A. Zisserman, "Multiple View Geometry in Computer Vision", 2nd Ed, Cambridge 2003

Constructor Summary

Constructors

Constructor	Description
TrifocalExtractGeometries()

Method Summary

Modifier and Type	Method	Description
void	extractCamera(DMatrixRMaj P2, DMatrixRMaj P3)	Extract the camera matrices up to a common projective transform.
void	extractEpipoles(Point3D_F64 e2, Point3D_F64 e3)	Extracts the epipoles from the trifocal tensor.
void	extractFundmental(DMatrixRMaj F21, DMatrixRMaj F31)	Extract the fundamental matrices between views 1 + 2 and views 1 + 3.
void	setTensor(TrifocalTensor tensor)	Specifies the input tensor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TrifocalExtractGeometries

public TrifocalExtractGeometries()

Method Details

setTensor

public void setTensor(TrifocalTensor tensor)

Specifies the input tensor. The epipoles are immediately extracted since they are needed to extract all other data structures

Parameters:

tensor - The tensor. Reference is saved but not modified

extractEpipoles

public void extractEpipoles(Point3D_F64 e2,
 Point3D_F64 e3)

Extracts the epipoles from the trifocal tensor. Extracted epipoles will have a norm of 1 as an artifact of using SVD.

Parameters:

e2 - Output: Epipole in image 2. Homogeneous coordinates. Modified

e3 - Output: Epipole in image 3. Homogeneous coordinates. Modified

extractCamera

public void extractCamera(DMatrixRMaj P2,
 DMatrixRMaj P3)

Extract the camera matrices up to a common projective transform.

P2 = [[T1.T2.T3]e3|e2] and P3=[(e3*e2^T-I)[T1',T2',T3'|e2|e3]

NOTE: The camera matrix for the first view is assumed to be P1 = [I|0].

Parameters:

P2 - Output: 3x4 camera matrix for views 2. Modified.

P3 - Output: 3x4 camera matrix for views 3. Modified.

extractFundmental

public void extractFundmental(DMatrixRMaj F21,
 DMatrixRMaj F31)

Extract the fundamental matrices between views 1 + 2 and views 1 + 3. The returned Fundamental matrices will have the following properties: x_i^T*Fi*x₁ = 0, where i is view 2 or 3.

NOTE: The first camera is assumed to have the camera matrix of P1 = [I|0]. Thus observations in pixels for the first camera will not meet the epipolar constraint when applied to the returned fundamental matrices.

 F21=[e2]x *[T1,T2,T3]*e3 and F31 = [e3]x*[T1,T2,T3]*e3
 

Parameters:

F21 - (Output) Fundamental matrix

F31 - (Output) Fundamental matrix