Added shape fit function that iterates shape and blendshape fitting

CMakeLists.txt

@@ -101,6 +101,7 @@ set(HEADERS
 	include/eos/fitting/linear_shape_fitting.hpp
 	include/eos/fitting/contour_correspondence.hpp
 	include/eos/fitting/blendshape_fitting.hpp
+	include/eos/fitting/fitting.hpp
 	include/eos/render/Mesh.hpp
 	include/eos/render/utils.hpp
 	include/eos/render/render.hpp

include/eos/fitting/fitting.hpp

+/*
+ * Eos - A 3D Morphable Model fitting library written in modern C++11/14.
+ *
+ * File: include/eos/fitting/fitting.hpp
+ *
+ * Copyright 2015 Patrik Huber
+ *
+ * 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.
+ */
+#pragma once
+
+#ifndef FITTING_HPP_
+#define FITTING_HPP_
+
+#include "eos/morphablemodel/MorphableModel.hpp"
+#include "eos/morphablemodel/Blendshape.hpp"
+#include "eos/fitting/linear_shape_fitting.hpp"
+#include "eos/fitting/blendshape_fitting.hpp"
+
+#include "opencv2/core/core.hpp"
+
+#include <vector>
+
+namespace eos {
+	namespace fitting {
+
+/**
+ * Convenience function that fits the shape model and expression blendshapes to
+ * landmarks. It iterates PCA-shape and blendshape fitting until convergence
+ * (usually it converges within 5 to 10 iterations).
+ *
+ * Note/Todo: It would be great if the function gave access to the shape and
+ * blendshape coefficients. Maybe add them as optional out parameters?
+ *
+ * @param[in] affine_camera_matrix The estimated pose as a 3x4 affine camera matrix that is used to fit the shape.
+ * @param[in] morphable_model The 3D Morphable Model used for the shape fitting.
+ * @param[in] blendshapes A vector of blendshapes that are being fit to the landmarks in addition to the PCA model.
+ * @param[in] image_points 2D landmarks from an image to fit the model to.
+ * @param[in] vertex_indices The vertex indices in the model that correspond to the 2D points.
+ * @param[in] lambda Regularisation parameter of the PCA shape fitting.
+ * @return The fitted model shape instance.
+ */
+cv::Mat fit_shape_model(cv::Mat affine_camera_matrix, eos::morphablemodel::MorphableModel morphable_model, std::vector<eos::morphablemodel::Blendshape> blendshapes, std::vector<cv::Vec2f> image_points, std::vector<int> vertex_indices, float lambda = 3.0f)
+{
+	using cv::Mat;
+	
+	Mat blendshapes_as_basis(blendshapes[0].deformation.rows, blendshapes.size(), CV_32FC1); // assert blendshapes.size() > 0 and all of them have same number of rows, and 1 col
+	for (int i = 0; i < blendshapes.size(); ++i)
+	{
+		blendshapes[i].deformation.copyTo(blendshapes_as_basis.col(i));
+	}
+
+	std::vector<float> last_blendshape_coeffs, current_blendshape_coeffs; 
+	std::vector<float> last_pca_coeffs, current_pca_coeffs;
+	current_blendshape_coeffs.resize(blendshapes.size()); // starting values t_0, all zeros
+	current_pca_coeffs.resize(morphable_model.get_shape_model().get_num_principal_components()); // starting values, all zeros
+	Mat combined_shape;
+
+	do // run at least once:
+	{
+		last_blendshape_coeffs = current_blendshape_coeffs;
+		last_pca_coeffs = current_pca_coeffs;
+		// Estimate the PCA shape coefficients with the current blendshape coefficients (0 in the first iteration):
+		Mat mean_plus_blendshapes = morphable_model.get_shape_model().get_mean() + blendshapes_as_basis * Mat(last_blendshape_coeffs);
+		current_pca_coeffs = fitting::fit_shape_to_landmarks_linear(morphable_model, affine_camera_matrix, image_points, vertex_indices, mean_plus_blendshapes, lambda);
+
+		// Estimate the blendshape coefficients with the current PCA model estimate:
+		Mat pca_model_shape = morphable_model.get_shape_model().draw_sample(current_pca_coeffs);
+		current_blendshape_coeffs = eos::fitting::fit_blendshapes_to_landmarks_linear(blendshapes, pca_model_shape, affine_camera_matrix, image_points, vertex_indices, 0.0f);
+
+		combined_shape = pca_model_shape + blendshapes_as_basis * Mat(current_blendshape_coeffs);
+	} while (std::abs(cv::norm(current_pca_coeffs) - cv::norm(last_pca_coeffs)) >= 0.01 || std::abs(cv::norm(current_blendshape_coeffs) - cv::norm(last_blendshape_coeffs)) >= 0.01);
+	
+	return combined_shape;
+};
+
+	} /* namespace fitting */
+} /* namespace eos */
+
+#endif /* FITTING_HPP_ */