1 // Ceres Solver - A fast non-linear least squares minimizer 2 // Copyright 2012 Google Inc. All rights reserved. 3 // http://code.google.com/p/ceres-solver/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are met: 7 // 8 // * Redistributions of source code must retain the above copyright notice, 9 // this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above copyright notice, 11 // this list of conditions and the following disclaimer in the documentation 12 // and/or other materials provided with the distribution. 13 // * Neither the name of Google Inc. nor the names of its contributors may be 14 // used to endorse or promote products derived from this software without 15 // specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 // POSSIBILITY OF SUCH DAMAGE. 28 // 29 // Author: strandmark (at) google.com (Petter Strandmark) 30 // 31 // Class for loading the data required for descibing a Fields of Experts (FoE) 32 // model. The Fields of Experts regularization consists of terms of the type 33 // 34 // alpha * log(1 + (1/2)*sum(F .* X)^2), 35 // 36 // where F is a d-by-d image patch and alpha is a constant. This is implemented 37 // by a FieldsOfExpertsSum object which represents the dot product between the 38 // image patches and a FieldsOfExpertsLoss which implements the log(1 + (1/2)s) 39 // part. 40 // 41 // [1] S. Roth and M.J. Black. "Fields of Experts." International Journal of 42 // Computer Vision, 82(2):205--229, 2009. 43 44 #ifndef CERES_EXAMPLES_FIELDS_OF_EXPERTS_H_ 45 #define CERES_EXAMPLES_FIELDS_OF_EXPERTS_H_ 46 47 #include <iostream> 48 #include <vector> 49 50 #include "ceres/loss_function.h" 51 #include "ceres/cost_function.h" 52 #include "ceres/sized_cost_function.h" 53 54 #include "pgm_image.h" 55 56 namespace ceres { 57 namespace examples { 58 59 // One sum in the FoE regularizer. This is a dot product between a filter and an 60 // image patch. It simply calculates the dot product between the filter 61 // coefficients given in the constructor and the scalar parameters passed to it. 62 class FieldsOfExpertsCost : public ceres::CostFunction { 63 public: 64 explicit FieldsOfExpertsCost(const std::vector<double>& filter); 65 // The number of scalar parameters passed to Evaluate must equal the number of 66 // filter coefficients passed to the constructor. 67 virtual bool Evaluate(double const* const* parameters, 68 double* residuals, 69 double** jacobians) const; 70 71 private: 72 const std::vector<double>& filter_; 73 }; 74 75 // The loss function used to build the correct regularization. See above. 76 // 77 // f(x) = alpha_i * log(1 + (1/2)s) 78 // 79 class FieldsOfExpertsLoss : public ceres::LossFunction { 80 public: 81 explicit FieldsOfExpertsLoss(double alpha) : alpha_(alpha) { } 82 virtual void Evaluate(double, double*) const; 83 84 private: 85 const double alpha_; 86 }; 87 88 // This class loads a set of filters and coefficients from file. Then the users 89 // obtains the correct loss and cost functions through NewCostFunction and 90 // NewLossFunction. 91 class FieldsOfExperts { 92 public: 93 // Creates an empty object with size() == 0. 94 FieldsOfExperts(); 95 // Attempts to load filters from a file. If unsuccessful it returns false and 96 // sets size() == 0. 97 bool LoadFromFile(const std::string& filename); 98 99 // Side length of a square filter in this FoE. They are all of the same size. 100 int Size() const { 101 return size_; 102 } 103 104 // Total number of pixels the filter covers. 105 int NumVariables() const { 106 return size_ * size_; 107 } 108 109 // Number of filters used by the FoE. 110 int NumFilters() const { 111 return num_filters_; 112 } 113 114 // Creates a new cost function. The caller is responsible for deallocating the 115 // memory. alpha_index specifies which filter is used in the cost function. 116 ceres::CostFunction* NewCostFunction(int alpha_index) const; 117 // Creates a new loss function. The caller is responsible for deallocating the 118 // memory. alpha_index specifies which filter this loss function is for. 119 ceres::LossFunction* NewLossFunction(int alpha_index) const; 120 121 // Gets the delta pixel indices for all pixels in a patch. 122 const std::vector<int>& GetXDeltaIndices() const { 123 return x_delta_indices_; 124 } 125 const std::vector<int>& GetYDeltaIndices() const { 126 return y_delta_indices_; 127 } 128 129 private: 130 // The side length of a square filter. 131 int size_; 132 // The number of different filters used. 133 int num_filters_; 134 // Pixel offsets for all variables. 135 std::vector<int> x_delta_indices_, y_delta_indices_; 136 // The coefficients in front of each term. 137 std::vector<double> alpha_; 138 // The filters used for the dot product with image patches. 139 std::vector<std::vector<double> > filters_; 140 }; 141 142 } // namespace examples 143 } // namespace ceres 144 145 #endif // CERES_EXAMPLES_FIELDS_OF_EXPERTS_H_ 146
