boofcv.alg.geo.triangulate

Class PixelDepthLinear

java.lang.Object

boofcv.alg.geo.triangulate.PixelDepthLinear

public class PixelDepthLinear
extends Object

Computes the depth (value of z-axis in frame A) for a single point feature given N observations and N-1 rigid camera transforms. The estimate will be optimal an algebraic sense, but not in a Euclidean sense. Two variants are provided in this class, for 2 views and N>1 views. All pixel coordinates are in calibrated units.

This linear estimation of pixel depth is done using the following equation:
λ₁*hat(x₂)*R*x₁ + hat(x₂)*T = 0
where λ₁ is the pixel depth in the first image, x is an observation in calibrated homogeneous coordinates, and (R,T) is a rigid body transformation. Modified implementation of the algorithm described in [1].

To go from pixel depth to a 3D coordinate simply multiply the observation in calibrated (z=1) homogeneous coordinates by the returned depth.

[1] Page 267 in Y. Ma, S. Soatto, J. Kosecka, and S. S. Sastry, "An Invitation to 3-D Vision" Springer-Verlad, 2004

Author:

Peter Abeles

Constructor Summary

Constructors

Constructor and Description
PixelDepthLinear()

Method Summary

Methods

Modifier and Type	Method and Description
double	depth2View(georegression.struct.point.Point2D_F64 a, georegression.struct.point.Point2D_F64 b, georegression.struct.se.Se3_F64 fromAtoB) Computes pixel depth in image 'a' from two observations.
double	depthNView(List<georegression.struct.point.Point2D_F64> obs, List<georegression.struct.se.Se3_F64> motion) Computes the pixel depth from N views of the same object.

Methods inherited from class java.lang.Object

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

Constructor Detail

PixelDepthLinear

public PixelDepthLinear()

Method Detail

depthNView

public double depthNView(List<georegression.struct.point.Point2D_F64> obs,
                List<georegression.struct.se.Se3_F64> motion)

Computes the pixel depth from N views of the same object. Pixel depth in the first frame.

Parameters:

obs - List of observations on a single feature in normalized coordinates

motion - List of camera motions. Each index 'i' is the motion from view 0 to view i+1.

Returns:

depth of the pixels

depth2View

public double depth2View(georegression.struct.point.Point2D_F64 a,
                georegression.struct.point.Point2D_F64 b,
                georegression.struct.se.Se3_F64 fromAtoB)

Computes pixel depth in image 'a' from two observations.

Parameters:

a - Observation in first frame. In calibrated coordinates. Not modified.

b - Observation in second frame. In calibrated coordinates. Not modified.

fromAtoB - Transform from frame a to frame b.

Returns:

Pixel depth in first frame. In same units as T inside of fromAtoB.