Class NormalPriorPose3DCostFunctor

Class Documentation

class NormalPriorPose3DCostFunctor

Create a prior cost function on both the 3D position and orientation variables at once.

The Ceres::NormalPrior cost function only supports a single variable. This is a convenience cost function that applies a prior constraint on both the 3D position and orientation variables at once.

The cost function is of the form:

cost(x) = || A * [ p - b(0:2) ] ||^2 || [ AngleAxis(b(3:6)^-1 * q) ] ||

where, the matrix A and the vector b are fixed, p is the position variable, and q is the orientation variable. Note that the covariance submatrix for the quaternion is 3x3, representing errors in the orientation local parameterization tangent space. In case the user is interested in implementing a cost function of the form

cost(X) = (X - mu)^T S^{-1} (X - mu)

where, mu is a vector and S is a covariance matrix, then, A = S^{-1/2}, i.e the matrix A is the square root information matrix (the inverse of the covariance).

Public Functions

NormalPriorPose3DCostFunctor(const fuse_core::Matrix6d &A, const fuse_core::Vector7d &b)

Construct a cost function instance.

Parameters:
  • A[in] The residual weighting matrix, most likely the square root information matrix in order (x, y, z, qx, qy, qz)

  • b[in] The 3D pose measurement or prior in order (x, y, z, qw, qx, qy, qz)

template<typename T>
bool operator()(const T *const position, const T *const orientation, T *residual) const

Evaluate the cost function. Used by the Ceres optimization engine.