Opencv 2形態学フィルタリングを用いて画像のエッジおよび角点検出を行う
4266 ワード
#if !defined MORPHOF
#define MORPHOF
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
class MorphoFeatures {
private:
// threshold to produce binary image
int threshold;
// structuring elements used in corner detection
cv::Mat cross;
cv::Mat diamond;
cv::Mat square;
cv::Mat x;
void applyThreshold(cv::Mat& result) {
// Apply threshold on result
if (threshold>0)
cv::threshold(result, result, threshold, 255, cv::THRESH_BINARY_INV);
}
public:
MorphoFeatures() : threshold(-1), cross(5,5,CV_8U,cv::Scalar(0)),
diamond(5,5,CV_8U,cv::Scalar(1)),
square(5,5,CV_8U,cv::Scalar(1)),
x(5,5,CV_8U,cv::Scalar(0)){
// Creating the cross-shaped structuring element
for (int i=0; i<5; i++) {
cross.at<uchar>(2,i)= 1;
cross.at<uchar>(i,2)= 1;
}
// Creating the diamond-shaped structuring element
diamond.at<uchar>(0,0)= 0;
diamond.at<uchar>(0,1)= 0;
diamond.at<uchar>(1,0)= 0;
diamond.at<uchar>(4,4)= 0;
diamond.at<uchar>(3,4)= 0;
diamond.at<uchar>(4,3)= 0;
diamond.at<uchar>(4,0)= 0;
diamond.at<uchar>(4,1)= 0;
diamond.at<uchar>(3,0)= 0;
diamond.at<uchar>(0,4)= 0;
diamond.at<uchar>(0,3)= 0;
diamond.at<uchar>(1,4)= 0;
// Creating the x-shaped structuring element
for (int i=0; i<5; i++) {
x.at<uchar>(i,i)= 1;
x.at<uchar>(4-i,i)= 1;
}
}
void setThreshold(int t) {
threshold= t;
}
int getThreshold() const {
return threshold;
}
cv::Mat getEdges(const cv::Mat &image) {
// Get the gradient image
cv::Mat result;
cv::morphologyEx(image,result,cv::MORPH_GRADIENT,cv::Mat());
// Apply threshold to obtain a binary image
applyThreshold(result);
return result;
}
cv::Mat getCorners(const cv::Mat &image) {
cv::Mat result;
// Dilate with a cross
cv::dilate(image,result,cross);
// Erode with a diamond
cv::erode(result,result,diamond);
cv::Mat result2;
// Dilate with a X
cv::dilate(image,result2,x);
// Erode with a square
cv::erode(result2,result2,square);
// Corners are obtained by differencing
// the two closed images
cv::absdiff(result2,result,result);
// Apply threshold to obtain a binary image
applyThreshold(result);
return result;
}
void drawOnImage(const cv::Mat& binary, cv::Mat& image) {
cv::Mat_<uchar>::const_iterator it= binary.begin<uchar>();
cv::Mat_<uchar>::const_iterator itend= binary.end<uchar>();
// for each pixel
for (int i=0; it!= itend; ++it,++i) {
if (!*it)
cv::circle(image,cv::Point(i%image.step,i/image.step),5,cv::Scalar(255,0,0));
}
}
};
#endif
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include "morphoFeatures.h"
int main()
{
// Read input image
cv::Mat image= cv::imread("d:/test/opencv/building.jpg",0);
if (!image.data)
return 0;
// Display the image
cv::namedWindow("Image");
cv::imshow("Image",image);
// Create the morphological features instance
MorphoFeatures morpho;
morpho.setThreshold(40);
// Get the edges
cv::Mat edges;
edges= morpho.getEdges(image);
// Display the edge image
cv::namedWindow("Edge Image");
cv::imshow("Edge Image",edges);
// Get the corners
morpho.setThreshold(-1);
cv::Mat corners;
corners= morpho.getCorners(image);
cv::morphologyEx(corners,corners,cv::MORPH_TOPHAT,cv::Mat());
cv::threshold(corners, corners, 40, 255, cv::THRESH_BINARY_INV);
// Display the corner image
cv::namedWindow("Corner Image");
cv::imshow("Corner Image",corners);
// Display the corner on the image
morpho.drawOnImage(corners,image);
cv::namedWindow("Corners on Image");
cv::imshow("Corners on Image",image);
cv::waitKey();
return 0;
}