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@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 56namespace ceres { 57namespace 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. 62class 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// 79class 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. 91class 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