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105 lines
2.8 KiB
105 lines
2.8 KiB
#include "fingerprint.hpp"
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#include "wavelet.hpp"
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#include "utilities.hpp"
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#include <ostream>
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#include <cmath>
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rgb_wavelet_coefficients rgb_wavelet_coefficients::calculate(const raw_rgb_image& image){
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rgb_wavelet_coefficients ret;
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std::vector<double> vector(make_u(image.width() * image.height()));
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// for every color
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for(unsigned int color = 0; color < 3; ++color){
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auto& coefficient_array = color == 0 ? ret.reds : (color == 1 ? ret.greens : ret.blues);
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unsigned int array_index = 0;
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for(unsigned int n = 0; n < make_u(image.width() * image.height()); ++n){
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vector[n] = 2.0 * image.data[3*n + color] / double(255) - 1.0;
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}
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wvlt::wavelet_2D(vector.data(), make_u(image.width()), make_u(image.height()));
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auto copy = vector;
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for(auto & x : copy) x = std::abs(x);
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auto n_coefficients = coefficient_array.size();
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std::nth_element(copy.begin(), copy.begin() + n_coefficients, copy.end(), std::greater<double>());
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double threshold = copy[n_coefficients-1];
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for(unsigned int n = 0; n < vector.size(); ++n){
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auto x = vector[n];
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if(std::abs(x) >= threshold) {
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coefficient_array[array_index++] = std::make_pair(n, x);
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}
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if(array_index >= coefficient_array.size()) {
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break;
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}
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}
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}
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return ret;
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}
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static double square(double x){
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return x*x;
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}
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double rgb_wavelet_coefficients::distance_to(const rgb_wavelet_coefficients& y) const {
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double distance = 0;
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for(unsigned int color = 0; color < 3; ++color){
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unsigned int i = 0, j = 0;
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auto& x_array = color == 0 ? reds : (color == 1 ? greens : blues);
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auto& y_array = color == 0 ? y.reds : (color == 1 ? y.greens : y.blues);
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// "merge"
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while(i < x_array.size() && j < y_array.size()){
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auto x_pair = x_array[i];
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auto y_pair = y_array[j];
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if(x_pair.first == y_pair.first) {
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distance += square(y_pair.second - x_pair.second);
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++i;
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++j;
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} else if(x_pair.first < y_pair.first) {
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distance += square(x_pair.second);
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++i;
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} else {
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distance += square(y_pair.second);
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++j;
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}
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}
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// remaining part, either x or y
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for(; i < x_array.size(); ++i){
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distance += square(x_array[i].second);
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}
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for(; j < y_array.size(); ++j){
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distance += square(y_array[j].second);
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}
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}
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return distance;
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}
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namespace std {
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template <typename U, typename V>
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ostream& operator<<(ostream& out, pair<U, V> const & p){
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return out << '(' << p.first << ", " << p.second << ')';
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}
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}
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std::ostream& operator<<(std::ostream& out, rgb_wavelet_coefficients const & x){
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out << "rgb_wavelet_coefficients" << std::endl;
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for(int color = 0; color < 3; ++color){
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auto& coefficient_array = color == 0 ? x.reds : (color == 1 ? x.greens : x.blues);
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out << '[' << coefficient_array[0];
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for(unsigned int i = 1; i < coefficient_array.size(); ++i) out << ", " << coefficient_array[i];
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out << ']' << std::endl;
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}
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return out;
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}
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