当前位置：首页 > news >正文

[C++][opencv]基于opencv实现photoshop算法色阶调整

news 来源：原创 2024/9/18 5:12:33

【测试环境】

vs2019

opencv==4.8.0

【效果演示】

【核心实现代码】

Levels.hpp

#ifndef OPENCV2_PS_LEVELS_HPP_
#define OPENCV2_PS_LEVELS_HPP_#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;namespace cv {/*** Class of Level for one channel*/
class Level {
public:int   Shadow;  //输入色阶黑点值float Midtones; //输入色阶灰点值（注意是浮点数）int   Highlight; //输入色阶白点值int   OutputShadow; //输出色阶黑点值int   OutputHighlight; //输出色阶白点值Level();virtual ~Level();bool createColorTable(uchar * colorTable);void clear();
};/*** Class of Levels for all channels*/
class Levels {
protected:bool createColorTables(uchar colorTables[][256]);public:Level RGBChannel;  //RGB整体调整Level RedChannel;  //红色通道Level GreenChannel; //绿色通道Level BlueChannel; //蓝色通道Levels();virtual ~Levels();int adjust(InputArray src, OutputArray dst); //实施色阶调整
};} /* namespace cv */#endif /* OPENCV2_PS_LEVELS_HPP_ */

Levels.cpp

#include "Levels.hpp"namespace cv {Level::Level() {clear();
}Level::~Level() {}void Level::clear() {Shadow = OutputShadow = 0;Highlight = OutputHighlight = 255;Midtones = 1.0;
}//create color table for a channel
bool Level::createColorTable(uchar * colorTable)
{int diff = (int)(Highlight - Shadow);int outDiff = (int)(OutputHighlight - OutputShadow);if (!((Highlight <= 255 && diff <= 255 && diff >= 2) ||(OutputShadow <= 255 && OutputHighlight <= 255 && outDiff < 255) ||(!(Midtones > 9.99 && Midtones > 0.1) && Midtones != 1.0)))return false;double coef = 255.0 / diff;double outCoef = outDiff / 255.0;double exponent = 1.0 / Midtones;for (int i = 0; i < 256; i ++){int v;// calculate black field and white field of input levelif ( colorTable[i] <= (uchar)Shadow ) {v = 0;} else {v = (int)((colorTable[i] - Shadow) * coef + 0.5);if (v > 255) v = 255;}// calculate midtone field of input levelv = (int)( pow(v / 255.0, exponent) * 255.0 + 0.5 );// calculate output levelcolorTable[i] = (uchar)( v * outCoef + OutputShadow + 0.5 );}return true;
}//==================================================================
// LevelsLevels::Levels() {
}Levels::~Levels() {}bool Levels::createColorTables(uchar colorTables[][256])
{bool result = false;int i, j;//initialize color tablefor (i = 0; i < 3; i ++) {for (j = 0; j < 256; j ++)colorTables[i][j] = (uchar)j;}//create color table for each channelresult = BlueChannel.createColorTable( colorTables[0]);result = GreenChannel.createColorTable( colorTables[1]);result = RedChannel.createColorTable( colorTables[2]);result = RGBChannel.createColorTable( colorTables[0]);result = RGBChannel.createColorTable( colorTables[1]);result = RGBChannel.createColorTable( colorTables[2]);return result;
}int Levels::adjust(InputArray src, OutputArray dst)
{Mat input = src.getMat();if( input.empty() ) {return -1;}dst.create(src.size(), src.type());Mat output = dst.getMat();const uchar *in;uchar *out;int width = input.cols;int height = input.rows;int channels = input.channels();uchar colorTables[3][256];//create color tablesif ( ! createColorTables( colorTables ) )  {//error create color table"return 1;}//adjust each pixel#ifdef HAVE_OPENMP#pragma omp parallel for#endiffor (int y = 0; y < height; y ++) {in = input.ptr<uchar>(y);out = output.ptr<uchar>(y);for (int x = 0; x < width; x ++) {for (int c = 0; c < 3; c++) {*out++ = colorTables[c][*in++];}for (int c = 0; c < channels - 3; c++) {*out++ = *in++;}}}return 0;
}} /* namespace cv */

【完整演示代码下载】

https://download.csdn.net/download/FL1623863129/89632958