105 lines
2.7 KiB
C++
105 lines
2.7 KiB
C++
#pragma once
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#include <memory>
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#include <vector>
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#include <opencv2/opencv.hpp>
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std::vector<double> caculate_abcd(std::vector<std::pair<double, double>> point)
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{
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int MaxElement = point.size() - 1;
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//计算常数f
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double f = point[0].second;
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//求解
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int n, m;
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std::vector<std::vector<double>> a;
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for (int i = 0; i < MaxElement; i++)
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{
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std::vector<double> b;
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b.resize(MaxElement + 1);
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a.push_back(b);
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}
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for (int i = 0; i < MaxElement; i++)
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{
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for (int j = 0; j < MaxElement; j++)
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a[i][j] = pow(point[i + 1].first, MaxElement - j);
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a[i][MaxElement] = point[i + 1].second - f;
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}
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int i, j;
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n = MaxElement;
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for (j = 0; j < n; j++)
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{
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double max = 0;
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double imax = 0;
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for (i = j; i < n; i++)
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{
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if (imax < fabs(a[i][j])) {
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imax = fabs(a[i][j]);
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max = a[i][j];//得到各行中所在列最大元素
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m = i;
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}
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}
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if (fabs(a[j][j]) != max)
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{
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double b = 0;
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for (int k = j; k < n + 1; k++) {
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b = a[j][k];
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a[j][k] = a[m][k];
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a[m][k] = b;
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}
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}
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for (int r = j; r < n + 1; r++)
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{
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a[j][r] = a[j][r] / max;//让该行的所在列除以所在列的第一个元素，目的是让首元素为1
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}
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for (i = j + 1; i < n; i++)
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{
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double c = a[i][j];
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if (c == 0.0) continue;
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for (int s = j; s < n + 1; s++) {
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a[i][s] = a[i][s] - a[j][s] * c;//前后行数相减，使下一行或者上一行的首元素为0
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}
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}
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}
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for (i = n - 2; i >= 0; i--)
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{
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for (j = i + 1; j < n; j++)
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{
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a[i][n] = a[i][n] - a[j][n] * a[i][j];
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}
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}
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std::vector<double> result;
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for (int k = 0; k < n; k++)
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result.push_back(a[k][n]);
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result.push_back(f);
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return result;
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}
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double caculate_value(const std::vector<double>& abcd, double x)
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{
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return abcd[0] * x * x * x + abcd[1] * x * x + abcd[2] * x + abcd[3];
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}
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void brightness(cv::Mat& lut, int alpha = 170)
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{
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std::vector<std::pair<double, double>> pos;
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pos.push_back(std::pair<double, double>(0, 0));
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pos.push_back(std::pair<double, double>(64, 64));
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pos.push_back(std::pair<double, double>(alpha, 255));
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pos.push_back(std::pair<double, double>(255, 255));
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std::vector<double> abcd = caculate_abcd(pos);
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uchar table[256];
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for (int i = 0; i < 256; i++)
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table[i] = static_cast<uchar>(caculate_value(abcd, i));
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uchar* ptr = lut.data;
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for (int i = 0, length = lut.total() * lut.channels(); i < length; i++)
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ptr[i] = table[ptr[i]];
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} |