作者:qr筱然陋室 | 来源:互联网 | 2023-06-08 09:25
一.调整图像亮度与对比度1.图像变换---像素变换-点操作---邻域操作-区域操作调整图像亮度和对比度属于像素变换-点操作公式为:g(i,j)αf(i,j)+β其中α&
一.调整图像亮度与对比度
1.图像变换
---像素变换-点操作
---邻域操作-区域操作
调整图像亮度和对比度属于像素变换-点操作
公式为:g(i,j) = αf(i,j) + β 其中α>0 ,β是增益变量
处理图像经常会对图像色彩进行增强,这就是改变图像的亮度β和对比度α,
我们看看实例代码:
1 #include
2 #include
3
4 using namespace std;
5 using namespace cv;
6 /*图像操作*/
7 int main(int argc, char **argv)
8 {
9 Mat src1 = imread("E:\\vsprom\\learn05\\v15.jpg");
10
11 if (src1.empty())
12 {
13 cout <<"can not load imagefile1...." << endl;
14 return -1;
15 }
16 namedWindow("in1 image win", CV_WINDOW_AUTOSIZE);
17 imshow("in1 image win", src1);
18
19 int height = src1.rows;
20 int width = src1.cols;
21
22 Mat dst = Mat::zeros(src1.size(), src1.type());//创建一副与src1同样的图像,并将像素值全部给0
23 float alpha = 1.2;
24 float beta = 30;
25 for (int row = 0; row )
26 {
27 for (int col = 0; col )
28 {
29 if (src1.channels() == 3)//三通道图像
30 {
31 float b = src1.at(row, col)[0];//通道1
32 float g = src1.at(row, col)[1];//通道2
33 float r = src1.at(row, col)[2];//通道3
34
35 dst.at(row, col)[0] = saturate_cast(b*alpha + beta);//使用公式
36 dst.at(row, col)[1] = saturate_cast(g*alpha + beta);
37 dst.at(row, col)[2] = saturate_cast(r*alpha + beta);
38
39 }
40 else if (src1.channels() == 1)//单通道图像
41 {
42 float v = src1.at(row, col);
43 dst.at(row, col) = saturate_cast(v*alpha + beta);
44 }
45 }
46 }
47 namedWindow("dst image win", CV_WINDOW_AUTOSIZE);
48 imshow("dst image win", dst);
49
50
51 waitKey(0);
52 return 0;
53 }
效果如下此时α=1.2,β=30
效果如下α=1.2,β=100时,此时更亮
效果如下α=5,β=30时,对比更明显
转换图像格式:
src2.convertTo(src1, CV_32F);
代码为:
#include
#include
using namespace std;
using namespace cv;
/*图像操作*/
int main(int argc, char **argv)
{
Mat src2 = imread("E:\\vsprom\\learn05\\v15.jpg");
if (src2.empty())
{
cout <<"can not load imagefile1...." << endl;
return -1;
}
namedWindow("in1 image win", CV_WINDOW_AUTOSIZE);
imshow("in1 image win", src2);
Mat src1;
src2.convertTo(src1, CV_32F);
int height = src1.rows;
int width = src1.cols;
Mat dst = Mat::zeros(src2.size(), src2.type());//创建一副与src1同样的图像,并将像素值全部给0
float alpha = 1.2;
float beta = 30;
for (int row = 0; row )
{
for (int col = 0; col )
{
if (src1.channels() == 3)//三通道图像
{
float b = src1.at(row, col)[0];//通道1
float g = src1.at(row, col)[1];//通道2
float r = src1.at(row, col)[2];//通道3
//修改像素值
dst.at(row, col)[0] = saturate_cast(b*alpha + beta);
dst.at(row, col)[1] = saturate_cast(g*alpha + beta);
dst.at(row, col)[2] = saturate_cast(r*alpha + beta);
}
else if (src1.channels() == 1)//单通道图像
{
float v = src1.at(row, col);
dst.at(row, col) = saturate_cast(v*alpha + beta);
}
}
}
namedWindow("dst image win", CV_WINDOW_AUTOSIZE);
imshow("dst image win", dst);
waitKey(0);
return 0;
}
效果图: