Adding a denoising example using Fields of Experts.
We have permission from Stefan Roth to use the coefficients from his
Matlab toolbox. They have been added as *.foe files.
Change-Id: Ice529e5cab0302b9f27648dd3c8e5ed7b9662aba
diff --git a/examples/pgm_image.h b/examples/pgm_image.h
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+++ b/examples/pgm_image.h
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: strandmark@google.com (Petter Strandmark)
+//
+// Simple class for accessing PGM images.
+
+#ifndef CERES_EXAMPLES_PGM_IMAGE_H_
+#define CERES_EXAMPLES_PGM_IMAGE_H_
+
+#include <algorithm>
+#include <cstring>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "glog/logging.h"
+
+namespace ceres {
+namespace examples {
+
+template<typename Real>
+class PGMImage {
+ public:
+ // Create an empty image
+ PGMImage(int width, int height);
+ // Load an image from file
+ explicit PGMImage(std::string filename);
+ // Sets an image to a constant
+ void Set(double constant);
+
+ // Reading dimensions
+ int width() const;
+ int height() const;
+ int NumPixels() const;
+
+ // Get individual pixels
+ Real* MutablePixel(int x, int y);
+ Real Pixel(int x, int y) const;
+ Real* MutablePixelFromLinearIndex(int index);
+ Real PixelFromLinearIndex(int index) const;
+ int LinearIndex(int x, int y) const;
+
+ // Adds an image to another
+ void operator+=(const PGMImage& image);
+ // Adds a constant to an image
+ void operator+=(Real a);
+ // Multiplies an image by a constant
+ void operator*=(Real a);
+
+ // File access
+ bool WriteToFile(std::string filename) const;
+ bool ReadFromFile(std::string filename);
+
+ // Accessing the image data directly
+ bool SetData(const std::vector<Real>& new_data);
+ const std::vector<Real>& data() const;
+
+ protected:
+ int height_, width_;
+ std::vector<Real> data_;
+};
+
+// --- IMPLEMENTATION
+
+template<typename Real>
+PGMImage<Real>::PGMImage(int width, int height)
+ : height_(height), width_(width), data_(width*height, 0.0) {
+}
+
+template<typename Real>
+PGMImage<Real>::PGMImage(std::string filename) {
+ if (!ReadFromFile(filename)) {
+ height_ = 0;
+ width_ = 0;
+ }
+}
+
+template<typename Real>
+void PGMImage<Real>::Set(double constant) {
+ for (int i = 0; i < data_.size(); ++i) {
+ data_[i] = constant;
+ }
+}
+
+template<typename Real>
+int PGMImage<Real>::width() const {
+ return width_;
+}
+
+template<typename Real>
+int PGMImage<Real>::height() const {
+ return height_;
+}
+
+template<typename Real>
+int PGMImage<Real>::NumPixels() const {
+ return width_ * height_;
+}
+
+template<typename Real>
+Real* PGMImage<Real>::MutablePixel(int x, int y) {
+ return MutablePixelFromLinearIndex(LinearIndex(x, y));
+}
+
+template<typename Real>
+Real PGMImage<Real>::Pixel(int x, int y) const {
+ return PixelFromLinearIndex(LinearIndex(x, y));
+}
+
+template<typename Real>
+Real* PGMImage<Real>::MutablePixelFromLinearIndex(int index) {
+ CHECK(index >= 0);
+ CHECK(index < width_ * height_);
+ CHECK(index < data_.size());
+ return &data_[index];
+}
+
+template<typename Real>
+Real PGMImage<Real>::PixelFromLinearIndex(int index) const {
+ CHECK(index >= 0);
+ CHECK(index < width_ * height_);
+ CHECK(index < data_.size());
+ return data_[index];
+}
+
+template<typename Real>
+int PGMImage<Real>::LinearIndex(int x, int y) const {
+ return x + width_*y;
+}
+
+// Adds an image to another
+template<typename Real>
+void PGMImage<Real>::operator+= (const PGMImage<Real>& image) {
+ CHECK(data_.size() == image.data_.size());
+ for (int i = 0; i < data_.size(); ++i) {
+ data_[i] += image.data_[i];
+ }
+}
+
+// Adds a constant to an image
+template<typename Real>
+void PGMImage<Real>::operator+= (Real a) {
+ for (int i = 0; i < data_.size(); ++i) {
+ data_[i] += a;
+ }
+}
+
+// Multiplies an image by a constant
+template<typename Real>
+void PGMImage<Real>::operator*= (Real a) {
+ for (int i = 0; i < data_.size(); ++i) {
+ data_[i] *= a;
+ }
+}
+
+template<typename Real>
+bool PGMImage<Real>::WriteToFile(std::string filename) const {
+ std::ofstream outputfile(filename.c_str());
+ outputfile << "P2" << std::endl;
+ outputfile << "# PGM format" << std::endl;
+ outputfile << " # <width> <height> <levels> " << std::endl;
+ outputfile << " # <data> ... " << std::endl;
+ outputfile << width_ << ' ' << height_ << " 255 " << std::endl;
+
+ // Write data
+ int num_pixels = width_*height_;
+ for (int i = 0; i < num_pixels; ++i) {
+ // Convert to integer by rounding when writing file
+ outputfile << static_cast<int>(data_[i] + 0.5) << ' ';
+ }
+
+ return outputfile; // Returns true/false
+}
+
+namespace {
+
+// Helper function to read data from a text file, ignoring "#" comments.
+template<typename T>
+bool GetIgnoreComment(std::istream* in, T& t) {
+ std::string word;
+ bool ok;
+ do {
+ ok = true;
+ (*in) >> word;
+ if (word.length() > 0 && word[0] == '#') {
+ // Comment; read the whole line
+ ok = false;
+ std::getline(*in, word);
+ }
+ } while (!ok);
+
+ // Convert the string
+ std::stringstream sin(word);
+ sin >> t;
+
+ // Check for success
+ if (!in || !sin) {
+ return false;
+ }
+ return true;
+}
+} // namespace
+
+template<typename Real>
+bool PGMImage<Real>::ReadFromFile(std::string filename) {
+ std::ifstream inputfile(filename.c_str());
+
+ // File must start with "P2"
+ char ch1, ch2;
+ inputfile >> ch1 >> ch2;
+ if (!inputfile || ch1 != 'P' || (ch2 != '2' && ch2 != '5')) {
+ return false;
+ }
+
+ // Read the image header
+ int two_fifty_five;
+ if (!GetIgnoreComment(&inputfile, width_) ||
+ !GetIgnoreComment(&inputfile, height_) ||
+ !GetIgnoreComment(&inputfile, two_fifty_five) ) {
+ return false;
+ }
+ // Assert that the number of grey levels is 255.
+ if (two_fifty_five != 255) {
+ return false;
+ }
+
+ // Now read the data
+ int num_pixels = width_*height_;
+ data_.resize(num_pixels);
+ if (ch2 == '2') {
+ // Ascii file
+ for (int i = 0; i < num_pixels; ++i) {
+ int pixel_data;
+ bool res = GetIgnoreComment(&inputfile, pixel_data);
+ if (!res) {
+ return false;
+ }
+ data_[i] = pixel_data;
+ }
+ // There cannot be anything else in the file (except comments). Try reading
+ // another number and return failure if that succeeded.
+ int temp;
+ bool res = GetIgnoreComment(&inputfile, temp);
+ if (res) {
+ return false;
+ }
+ } else {
+ // Read the line feed character
+ if (inputfile.get() != '\n') {
+ return false;
+ }
+ // Binary file
+ // TODO(strandmark): Will not work on Windows (linebreak conversion).
+ for (int i = 0; i < num_pixels; ++i) {
+ unsigned char pixel_data = inputfile.get();
+ if (!inputfile) {
+ return false;
+ }
+ data_[i] = pixel_data;
+ }
+ // There cannot be anything else in the file. Try reading another byte
+ // and return failure if that succeeded.
+ inputfile.get();
+ if (inputfile) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+template<typename Real>
+bool PGMImage<Real>::SetData(const std::vector<Real>& new_data) {
+ // This function cannot change the dimensions
+ if (new_data.size() != data_.size()) {
+ return false;
+ }
+ std::copy(new_data.begin(), new_data.end(), data_.begin());
+ return true;
+}
+
+template<typename Real>
+const std::vector<Real>& PGMImage<Real>::data() const {
+ return data_;
+}
+
+} // namespace examples
+} // namespace ceres
+
+
+#endif // CERES_EXAMPLES_PGM_IMAGE_H_
