132 lines
3.1 KiB
C++
132 lines
3.1 KiB
C++
#include <opencv2/core.hpp>
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#include <opencv2/imgcodecs.hpp>
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#include <opencv2/imgproc/imgproc.hpp>
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#include <string>
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#include <iostream>
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#include <array>
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#include <fstream>
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using namespace cv;
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using namespace std;
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array<Mat, 3> getHistograms(const Mat &img);
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array<Mat, 3> getCumulativeHistograms(const Mat &img);
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array<array<uint16_t, 256>, 3> getLUT(const Mat &img, const array<Mat, 3> &refCumHist);
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Mat doLUT(const string &filename, const array<Mat, 3> &refCumHist);
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int main()
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{
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const constexpr size_t digitCount = 5;
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const constexpr size_t frameCount = 20505;
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auto refHistos = getCumulativeHistograms(imread("Frame00001.png", IMREAD_COLOR));
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for (size_t i = 2; i < frameCount; i++)
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{
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clog << "Processing frame: " << i << endl;
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string filename{ "Frame" };
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string numeric{ to_string(i) };
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filename += string(digitCount - numeric.size(), '0') + numeric + ".png";
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const auto lutted = doLUT(filename, refHistos);
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imwrite("processed/" + filename, lutted);
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}
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return 0;
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}
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array<Mat, 3> getHistograms(const Mat &img)
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{
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array<Mat, 3> compPlanes;
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split(img, compPlanes);
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const int histSize = 256;
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const float range[]{ 0.f, 256.f };
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const float* histRange{ range };
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bool uniform = true, accumulate = false;
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array<Mat, 3> histos;
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for (size_t i = 0u; i < 3; i++)
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calcHist(&compPlanes[i], 1, nullptr, Mat{}, histos[i], 1, &histSize, &histRange, uniform, accumulate);
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for (size_t histI = 0u; histI < histos.size(); histI++)
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{
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double histTotal = 0.0;
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for (size_t i = 0u; i < histos[histI].rows; i++)
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histTotal += histos[histI].at<float>(i);
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for (size_t i = 0u; i < histos[histI].rows; i++)
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histos[histI].at<float>(i) /= histTotal;
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}
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return histos;
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}
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array<Mat, 3> getCumulativeHistograms(const Mat &img)
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{
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auto histos = getHistograms(img);
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for (size_t histI = 0; histI < histos.size(); histI++)
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{
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double cumulativeTotal = 0.0;
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for (size_t i = 0; i < histos[histI].rows; i++)
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{
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cumulativeTotal += histos[histI].at<float>(i);
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histos[histI].at<float>(i) = cumulativeTotal;
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}
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}
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return histos;
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}
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array<array<uint16_t, 256>, 3> getLUT(const Mat &img, const array<Mat, 3> &refCumHist)
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{
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const auto cumulativeHistos = getCumulativeHistograms(img);
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array<array<uint16_t, 256>, 3> luts{};
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auto comp = [](float a, float b){ return (b - a) > 1.0e-6f; };
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for (size_t lut = 0; lut < luts.size(); lut++)
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{
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uint16_t targetBin = 1;
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for (uint16_t bin = 0; bin < luts[lut].size(); bin++)
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{
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while (comp(refCumHist[lut].at<float>(targetBin), cumulativeHistos[lut].at<float>(bin)) && targetBin < luts[lut].size())
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targetBin++;
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luts[lut][bin] = targetBin - 1;
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}
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}
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return luts;
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}
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Mat doLUT(const string &filename, const array<Mat, 3> &refCumHist)
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{
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Mat img{ imread(filename, IMREAD_COLOR) };
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if (!img.data)
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{
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cerr << "Failed to load image \'" << filename << "\'" << endl;
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return {};
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}
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const auto luts = getLUT(img, refCumHist);
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for (size_t x = 0; x < img.rows; x++)
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{
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for (size_t y = 0; y < img.cols; y++)
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{
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for (size_t c = 0; c < 3; c++)
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img.at<Vec3b>(x, y)[c] = luts[c][img.at<Vec3b>(x, y)[c]];
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}
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}
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return img;
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}
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