【原】OpenCV-PS羽化操作

作者：翟天保Steven
版权声明：著作权归作者所有，商业转载请联系作者获得授权，非商业转载请注明出处

功能函数

// 羽化
cv::Mat Eclosion(cv::Mat src, cv::Point center,float level)
{
if (level>0.9)
level = 0.9f;
float diff = (1-level) * (src.rows / 2 * src.rows / 2 + src.cols / 2 * src.cols / 2);
cv::Mat result = src.clone();
for (int i = 0; i < result.rows; ++i)
{
for (int j = 0; j < result.cols; ++j)
{
float dx = float(center.x - j);
float dy = float(center.y - i);
float ra = dx * dx + dy * dy;
float m = ((ra-diff) / diff * 255)>0? ((ra - diff) / diff * 255):0;
int b = result.at<Vec3b>(i, j)[0];
int g = result.at<Vec3b>(i, j)[1];
int r = result.at<Vec3b>(i, j)[2];
b = (int)(b+ m);
g = (int)(g + m);
r = (int)(r + m);
result.at<Vec3b>(i, j)[0] = (b > 255 ? 255 : (b < 0 ? 0 : b));
result.at<Vec3b>(i, j)[1] = (g > 255 ? 255 : (g < 0 ? 0 : g));
result.at<Vec3b>(i, j)[2] = (r > 255 ? 255 : (r < 0 ? 0 : r));
}
}
return result;
}

测试代码

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

cv::Mat Eclosion(cv::Mat src, cv::Point center, float level);

int main()
{
cv::Mat src = imread("test.jpg");

/***********       羽化   ***********************/
cv::Mat eclosion1 = Eclosion(src, cv::Point(src.cols / 2, src.rows / 2), 0.5f);
cv::Mat eclosion2 = Eclosion(src, cv::Point(src.cols / 2, src.rows / 2), 0.3f);
imshow("原图", src);
    imshow("羽化1", eclosion1);
imshow("羽化2", eclosion2);
waitKey(0);
return 0;
}

// 羽化
cv::Mat Eclosion(cv::Mat src, cv::Point center,float level)
{
if (level>0.9)
level = 0.9f;
float diff = (1-level) * (src.rows / 2 * src.rows / 2 + src.cols / 2 * src.cols / 2);
cv::Mat result = src.clone();
for (int i = 0; i < result.rows; ++i)
{
for (int j = 0; j < result.cols; ++j)
{
float dx = float(center.x - j);
float dy = float(center.y - i);
float ra = dx * dx + dy * dy;
float m = ((ra-diff) / diff * 255)>0? ((ra - diff) / diff * 255):0;
int b = result.at<Vec3b>(i, j)[0];
int g = result.at<Vec3b>(i, j)[1];
int r = result.at<Vec3b>(i, j)[2];
b = (int)(b+ m);
g = (int)(g + m);
r = (int)(r + m);
result.at<Vec3b>(i, j)[0] = (b > 255 ? 255 : (b < 0 ? 0 : b));
result.at<Vec3b>(i, j)[1] = (g > 255 ? 255 : (g < 0 ? 0 : g));
result.at<Vec3b>(i, j)[2] = (r > 255 ? 255 : (r < 0 ? 0 : r));
}
}
return result;
}

测试效果 

图1 原图

图2 羽化强度0.5效果图

图3 羽化强度0.3效果图

       本文提供的PS羽化操作函数，可以实现类似PS中羽化的效果，即目标区域中心区不变，边缘区模糊化，center参数是羽化中心，level是羽化强度，该值越大则羽化程度越大，使整张图被羽化的区域变大~

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