71 lines
2.7 KiB
C
71 lines
2.7 KiB
C
|
// Copyright 2020 The MediaPipe Authors.
|
||
|
|
//
|
||
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
// you may not use this file except in compliance with the License.
|
||
|
|
// You may obtain a copy of the License at
|
||
|
|
//
|
||
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
//
|
||
|
|
// Unless required by applicable law or agreed to in writing, software
|
||
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
// See the License for the specific language governing permissions and
|
||
|
|
// limitations under the License.
|
||
|
|
|
||
|
|
#ifndef MEDIAPIPE_FACE_GEOMETRY_LIBS_PROCRUSTES_SOLVER_H_
|
||
|
|
#define MEDIAPIPE_FACE_GEOMETRY_LIBS_PROCRUSTES_SOLVER_H_
|
||
|
|
|
||
|
|
#include <memory>
|
||
|
|
|
||
|
|
#include "Eigen/Dense"
|
||
|
|
#include "mediapipe/framework/port/status.h"
|
||
|
|
|
||
|
|
namespace mediapipe::face_geometry {
|
||
|
|
|
||
|
|
// Encapsulates a stateless solver for the Weighted Extended Orthogonal
|
||
|
|
// Procrustes (WEOP) Problem, as defined in Section 2.4 of
|
||
|
|
// https://doi.org/10.3929/ethz-a-004656648.
|
||
|
|
//
|
||
|
|
// Given the source and the target point clouds, the algorithm estimates
|
||
|
|
// a 4x4 transformation matrix featuring the following semantic components:
|
||
|
|
//
|
||
|
|
// * Uniform scale
|
||
|
|
// * Rotation
|
||
|
|
// * Translation
|
||
|
|
//
|
||
|
|
// The matrix maps the source point cloud into the target point cloud minimizing
|
||
|
|
// the Mean Squared Error.
|
||
|
|
class ProcrustesSolver {
|
||
|
|
public:
|
||
|
|
virtual ~ProcrustesSolver() = default;
|
||
|
|
|
||
|
|
// Solves the Weighted Extended Orthogonal Procrustes (WEOP) Problem.
|
||
|
|
//
|
||
|
|
// All `source_points`, `target_points` and `point_weights` must define the
|
||
|
|
// same number of points. Elements of `point_weights` must be non-negative.
|
||
|
|
//
|
||
|
|
// A too small diameter of either of the point clouds will likely lead to
|
||
|
|
// numerical instabilities and failure to estimate the transformation.
|
||
|
|
//
|
||
|
|
// A too small point cloud total weight will likely lead to numerical
|
||
|
|
// instabilities and failure to estimate the transformation too.
|
||
|
|
//
|
||
|
|
// Small point coordinate deviation for either of the point cloud will likely
|
||
|
|
// result in a failure as it will make the solution very unstable if possible.
|
||
|
|
//
|
||
|
|
// Note: the output `transform_mat` argument is used instead of `StatusOr<>`
|
||
|
|
// return type in order to avoid Eigen memory alignment issues. Details:
|
||
|
|
// https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
|
||
|
|
virtual absl::Status SolveWeightedOrthogonalProblem(
|
||
|
|
const Eigen::Matrix3Xf& source_points, //
|
||
|
|
const Eigen::Matrix3Xf& target_points, //
|
||
|
|
const Eigen::VectorXf& point_weights, //
|
||
|
|
Eigen::Matrix4f& transform_mat) const = 0;
|
||
|
|
};
|
||
|
|
|
||
|
|
std::unique_ptr<ProcrustesSolver> CreateFloatPrecisionProcrustesSolver();
|
||
|
|
|
||
|
|
} // namespace mediapipe::face_geometry
|
||
|
|
|
||
|
|
#endif // MEDIAPIPE_FACE_GEOMETRY_LIBS_PROCRUSTES_SOLVER_H_
|