系列文章:
用OpenCV实现Photoshop算法(一): 图像旋转
用OpenCV实现Photoshop算法(二): 图像剪切
用OpenCV实现Photoshop算法(三): 曲线调整
用OpenCV实现Photoshop算法(四): 色阶调整用OpenCV实现Photoshop算法(五): 亮度对比度调整
用OpenCV实现Photoshop算法(六): 变为黑白图像
用OpenCV实现Photoshop算法(七): 调整色相饱和度
用OpenCV实现Photoshop算法(八): 可选颜色
用OpenCV实现Photoshop算法(九): 高反差保留
八、可选颜色(Selective Color)
可选颜色是Photoshop的常用图像调整功能。 可以选定某些颜色进行调整,而不影响其它颜色。
可选颜色功能常用于创造某种色调。
首先选取颜色,有9种: 红、黄、绿、青、蓝、洋红、白、中性色、黑
然后,可以调整该颜色的 : 青、洋红、黄、黑 组成要素。
调整方法可以选择 相对 或 绝对 两种。
(一)可选颜色的原理
要了解相关原理,请参照这个博文: 关于可选颜色的计算公式
(二)OpenCV实现
1,我用OpenCV 编写了一个 SelectiveColor 类,实现可选颜色调整。在源文件 SelectiveColor.hpp, SelectiveColor.cpp中
3, 使用方法: SelectiveColor类有一个属性colors[9], 定义了9个颜色通道(红、黄、绿、青、蓝、洋红、白、中性色、黑)。
每个颜色通道有cyan, magenta, yellow, black 四个值。设置好所需通道和值,再调用SelectiveColor类的adjust()方法即可对图像进行 可选颜色调整。
4, 源文件及例程源码下载在这里: 可选颜色源码
(三)例程
使用SelectiveColor类,进行可选颜色调整。
#include
#include
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "SelectiveColor.hpp"
using namespace std;
using namespace cv;
static string window_name = "Photo";
static Mat src;
static Mat adjust_mat;
static string adjust_window = "Selective Color";
static int color = 2;
SelectiveColor selectiveColor;
vector points;
int cyan;
int magenta;
int yellow;
int black;
int is_absolute;
static void invalidate()
{
Mat dst;
selectiveColor.adjust(src, dst);
imshow(window_name, dst);
imshow(adjust_window, adjust_mat);
}
static void channelRead(int which)
{
color = which;
SelectiveColorAdjust * current = NULL;
if ( color >=0 && color <= 9)
current = &(selectiveColor.colors[color]);
if ( current == NULL ) return;
cyan = (current->cyan < 0) ? (current->cyan + 1) * 100 : current->cyan * 100;
magenta = (current->magenta < 0) ? (current->magenta + 1) * 100 : current->magenta * 100;
yellow = (current->yellow < 0) ? (current->yellow + 1) * 100 : current->yellow * 100;
black = (current->black < 0) ? (current->black + 1) * 100 : current->black * 100;
if ( selectiveColor.isAbsolute )
is_absolute = 1;
else
is_absolute = 0;
}
static void channelWrite()
{
SelectiveColorAdjust * current = NULL;
if ( color >=0 && color <= 9)
current = &(selectiveColor.colors[color]);
if ( current == NULL ) return;
current->cyan = (cyan - 100 ) / 100.0;
current->magenta = (magenta - 100 ) / 100.0;
current->yellow = (yellow - 100 ) / 100.0;
current->black = (black - 100 ) / 100.0;
selectiveColor.isAbsolute = ( is_absolute == 1 );
invalidate();
}
static void callbackAdjust(int , void *)
{
channelWrite();
invalidate();
}
static void callbackAdjustChannel(int , void *)
{
channelRead(color);
setTrackbarPos("cyan", adjust_window, cyan);
setTrackbarPos("magenta", adjust_window, magenta);
setTrackbarPos("yellow", adjust_window, yellow);
setTrackbarPos("black", adjust_window, black);
setTrackbarPos("Absolute", adjust_window, is_absolute);
invalidate();
}
static void callbackMouseEvent(int mouseEvent, int x, int y, int flags, void* param)
{
switch(mouseEvent) {
case CV_EVENT_LBUTTONDOWN:
break;
case CV_EVENT_MOUSEMOVE:
break;
case CV_EVENT_LBUTTONUP:
points.push_back(Point(x, y));
invalidate();
break;
case CV_EVENT_LBUTTONDBLCLK:
points.clear();
invalidate();
break;
}
return;
}
int main()
{
//read image file
src = imread("building.jpg");
if ( !src.data ) {
cout << "error read image" << endl;
return -1;
}
//create window
namedWindow(window_name);
imshow(window_name, src);
setMouseCallback(window_name, callbackMouseEvent, NULL );
//create window for levels
namedWindow(adjust_window);
adjust_mat = Mat::ones(100,400, CV_8UC3);
adjust_mat.setTo( Scalar(255,255,255) );
imshow(adjust_window, adjust_mat);
channelRead(0);
createTrackbar("Color", adjust_window, &color, 8, callbackAdjustChannel);
createTrackbar("cyan", adjust_window, &cyan, 200, callbackAdjust);
createTrackbar("magenta", adjust_window, &magenta, 200, callbackAdjust);
createTrackbar("yellow", adjust_window, &yellow, 200, callbackAdjust);
createTrackbar("black", adjust_window, &black, 200, callbackAdjust);
createTrackbar("Absolute", adjust_window, &is_absolute, 1, callbackAdjust);
waitKey();
return 0;
}
原图:
对红色 (color = 0 ), 进行调整后