应用：
五种方式将镜子中的“污点”的准 确位置找出来，并确定其大小、形状及面积。
代码：
代码语言：javascript复制#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/features2d.hpp>
#include <vector>
#include <map>
#include <iostream>
using namespace std;
using namespace cv;
static void help()
{
cout << "n This program demonstrates how to use BLOB to detect and filter region n"
"Usage: n"
" ./detect_blob <image1(detect_blob.png as default)>n"
"Press a key when image window is active to change descriptor";
}
static String Legende(SimpleBlobDetector::Params &pAct)
{
String s = "";
//blob通过面积过滤
if (pAct.filterByArea)
{
String inf = static_cast<const ostringstream&>(ostringstream() << pAct.minArea).str();
String sup = static_cast<const ostringstream&>(ostringstream() << pAct.maxArea).str();
s = " Area range [" inf " to " sup "]";
}
//blob通过圆过滤
if (pAct.filterByCircularity)
{
String inf = static_cast<const ostringstream&>(ostringstream() << pAct.minCircularity).str();
String sup = static_cast<const ostringstream&>(ostringstream() << pAct.maxCircularity).str();
if (s.length() == 0)
s = " Circularity range [" inf " to " sup "]";
else
s = " AND Circularity range [" inf " to " sup "]";
}
//blob通过颜色过滤
if (pAct.filterByColor)
{
String inf = static_cast<const ostringstream&>(ostringstream() << (int)pAct.blobColor).str();
if (s.length() == 0)
s = " Blob color " inf;
else
s = " AND Blob color " inf;
}
if (pAct.filterByConvexity)
{
String inf = static_cast<const ostringstream&>(ostringstream() << pAct.minConvexity).str();
String sup = static_cast<const ostringstream&>(ostringstream() << pAct.maxConvexity).str();
if (s.length() == 0)
s = " Convexity range[" inf " to " sup "]";
else
s = " AND Convexity range[" inf " to " sup "]";
}
if (pAct.filterByInertia)
{
String inf = static_cast<const ostringstream&>(ostringstream() << pAct.minInertiaRatio).str();
String sup = static_cast<const ostringstream&>(ostringstream() << pAct.maxInertiaRatio).str();
if (s.length() == 0)
s = " Inertia ratio range [" inf " to " sup "]";
else
s = " AND Inertia ratio range [" inf " to " sup "]";
}
return s;
}
int main(int argc, char *argv[])
{
String fileName;
cv::CommandLineParser parser(argc, argv, "{@input |detect_blob.png| }{h help | | }");
if (parser.has("h"))
{
help();
return 0;
}
fileName = parser.get<string>("@input");
Mat img = imread(fileName, IMREAD_COLOR);
if (img.empty())
{
cout << "Image " << fileName << " is empty or cannot be foundn";
return 1;
}
SimpleBlobDetector::Params pDefaultBLOB;
//核心参数
pDefaultBLOB.thresholdStep = 10;//步进阈值
pDefaultBLOB.minThreshold = 10;
pDefaultBLOB.maxThreshold = 220;
pDefaultBLOB.minRepeatability = 2;
pDefaultBLOB.minDistBetweenBlobs = 10;
//颜色过滤参数
pDefaultBLOB.filterByColor = false;
pDefaultBLOB.blobColor = 0;
//面积过滤参数
pDefaultBLOB.filterByArea = false;
pDefaultBLOB.minArea = 25;
pDefaultBLOB.maxArea = 5000;
pDefaultBLOB.filterByCircularity = false;
pDefaultBLOB.minCircularity = 0.9f;
pDefaultBLOB.maxCircularity = (float)1e37;
pDefaultBLOB.filterByInertia = false;
pDefaultBLOB.minInertiaRatio = 0.1f;
pDefaultBLOB.maxInertiaRatio = (float)1e37;
pDefaultBLOB.filterByConvexity = false;
pDefaultBLOB.minConvexity = 0.95f;
pDefaultBLOB.maxConvexity = (float)1e37;
// 参数初始化BLOB检测器
vector<String> typeDesc;
vector<SimpleBlobDetector::Params> pBLOB;
vector<SimpleBlobDetector::Params>::iterator itBLOB;
// Color palette
vector< Vec3b > palette;
for (int i = 0; i<65536; i )
{
uchar c1 = (uchar)rand();
uchar c2 = (uchar)rand();
uchar c3 = (uchar)rand();
palette.push_back(Vec3b(c1, c2, c3));
}
help();
typeDesc.push_back("BLOB"); // see http://docs.opencv.org/master/d0/d7a/classcv_1_1SimpleBlobDetector.html
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByArea = true;
pBLOB.back().minArea = 1;
pBLOB.back().maxArea = float(img.rows*img.cols);
// 1
typeDesc.push_back("BLOB");
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByArea = true;
pBLOB.back().minArea = 500;
pBLOB.back().maxArea = 2900;
//2
typeDesc.push_back("BLOB");
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByCircularity = true;
// 3
typeDesc.push_back("BLOB");
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByInertia = true;
pBLOB.back().minInertiaRatio = 0;
pBLOB.back().maxInertiaRatio = (float)0.2;
// 4
typeDesc.push_back("BLOB");
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByConvexity = true;
pBLOB.back().minConvexity = 0.;
pBLOB.back().maxConvexity = (float)0.9;
//5
typeDesc.push_back("BLOB");
pBLOB.push_back(pDefaultBLOB);
pBLOB.back().filterByColor = true;
pBLOB.back().blobColor = 0;
itBLOB = pBLOB.begin();
vector<double> desMethCmp;
Ptr<Feature2D> b;
String label;
vector<String>::iterator itDesc;
for (itDesc = typeDesc.begin(); itDesc != typeDesc.end(); itDesc)
{
vector<KeyPoint> keyImg1;
if (*itDesc == "BLOB")
{
b = SimpleBlobDetector::create(*itBLOB);//创建blob算子
label = Legende(*itBLOB); //选择过滤方式
itBLOB;
}
try
{
vector<KeyPoint> keyImg;
vector<Rect> zone;
vector<vector <Point> > region;
Mat desc, result(img.rows, img.cols, CV_8UC3);
if (b.dynamicCast<SimpleBlobDetector>().get())
{
Ptr<SimpleBlobDetector> sbd = b.dynamicCast<SimpleBlobDetector>();
sbd->detect(img, keyImg, Mat());
drawKeypoints(img, keyImg, result);
int i = 0;
for (vector<KeyPoint>::iterator k = keyImg.begin(); k != keyImg.end(); k, i)
circle(result, k->pt, (int)k->size, palette[i % 65536]);
}
namedWindow(*itDesc label, WINDOW_AUTOSIZE);
imshow(*itDesc label, result);
imshow("Original", img);
waitKey();
}
catch (const Exception& e)
{
cout << "Feature : " << *itDesc << "n";
cout << e.msg << endl;
}
}
return 0;
}
效果：
