boofcv.alg.geo.triangulate

Class PixelDepthLinear

java.lang.Object

boofcv.alg.geo.triangulate.PixelDepthLinear

public class PixelDepthLinear
extends java.lang.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

Constructor Summary

Constructors

Constructor and Description
PixelDepthLinear()

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Detail

PixelDepthLinear

public PixelDepthLinear()

Method Detail

depthNView

public double depthNView(java.util.List<Point2D_F64> obs,
                         java.util.List<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(Point2D_F64 a,
                         Point2D_F64 b,
                         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.