Can any one tell what wrong with the below code. I am getting segmentation fault while mouse moving last portion of the image. I am just printing R,G,B value according to the mouse position.
#include <iostream>
#include <stdio.h>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
Mat image;
char window_name[20]="Pixel Value Demo";
static void onMouse( int event, int x, int y, int f, void* ){
Vec3b pix=image.at<Vec3b>(x,y);
int B=pix.val[0];
int G=pix.val[1];
int R=pix.val[2];
cout<<R<<endl<<G<<endl<<B<<endl;
}
int main( int argc, char** argv )
{
namedWindow( window_name, CV_WINDOW_AUTOSIZE );
image = imread( "src.jpg");
imshow( window_name, image );
setMouseCallback( window_name, onMouse, 0 );
waitKey(0);
return 0;
}
Thanks in advance......
Vec3b pix=image.at<Vec3b>(x,y);
should be :
Vec3b pix=image.at<Vec3b>(y,x); // row,col !!
Related
The source image, it's result by gray converting from opencv.
cvtColor(img,COLOR_BGR2GRAY);
How I can convert this image to target:
histogram equalization function can be used to distribute intensity values range equally.
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>
using namespace cv;
using namespace std;
/** #function main */
int main( int argc, char** argv )
{
Mat src, dst;
char* source_window = "Source image";
char* equalized_window = "Equalized Image";
/// Load image
src = imread( "path_to_image", CV_LOAD_IMAGE_GRAYSCALE );
/// Convert to grayscale
//cvtColor( src, src, CV_BGR2GRAY );
/// Apply Histogram Equalization
equalizeHist( src, dst );
/// Display results
namedWindow( source_window, CV_WINDOW_AUTOSIZE );
namedWindow( equalized_window, CV_WINDOW_AUTOSIZE );
imshow( source_window, src );
imshow( equalized_window, dst );
/// Wait until user exits the program
waitKey(0);
return 0;
}
I am having doubt in opencv. I'm trying to implement SURF algorithm. When I trying to build the code but I'm getting the following error.
*****error LNK2019: unresolved external symbol _cvExtractSURF referenced in function _main
1>SAMPLE.obj : error LNK2019: unresolved external symbol _cvSURFParams referenced in function _main*****
I have gone through all the posts related to my topic in this forum, but couldn't figure out the problem with my code. Please help me in resolving my problem.
code :
#include <stdio.h>
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc_c.h>
#include <opencv2\objdetect\objdetect.hpp>
#include <opencv2\calib3d\calib3d.hpp>
#include <opencv2\core\core.hpp>
#include <opencv2\legacy\legacy.hpp>
#include <opencv2\legacy\compat.hpp>
#include <opencv2/nonfree/nonfree.hpp>
#include <opencv\opensurf\surf.h>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
CvMemStorage* storage = cvCreateMemStorage(0);
cvNamedWindow("Image", 1);
int key = 0;
static CvScalar red_color[] ={0,0,255};
IplImage* capture= cvLoadImage( "testface.jpg");
CvMat* prevgray = 0, *image = 0, *gray =0;
while( key != 'q' )
{
int firstFrame = gray == 0;
IplImage* frame =capture;
if(!frame)
break;
if(!gray)
{
image = cvCreateMat(frame->height, frame->width, CV_8UC1);
}
//Convert the RGB image obtained from camera into Grayscale
cvCvtColor(frame, image, CV_BGR2GRAY);
//Define sequence for storing surf keypoints and descriptors
CvSeq *imageKeypoints = 0, *imageDescriptors = 0;
int i;
//Extract SURF points by initializing parameters
CvSURFParams params = cvSURFParams(500,1);
cvExtractSURF( image, 0, &imageKeypoints, &imageDescriptors, storage, params );
printf("Image Descriptors: %d\n", imageDescriptors->total);
//draw the keypoints on the captured frame
for( i = 0; i < imageKeypoints->total; i++ )
{
CvSURFPoint* r = (CvSURFPoint*)cvGetSeqElem( imageKeypoints, i );
CvPoint center;
int radius;
center.x = cvRound(r->pt.x);
center.y = cvRound(r->pt.y);
radius = cvRound(r->size*1.2/9.*2);
cvCircle( frame, center, radius, red_color[0], 1, 8, 0 );
}
cvShowImage( "Image", frame );
cvWaitKey(0);
}
cvDestroyWindow("Image");
return 0
}
Thank you,
Sreelakshmi Priya
I want to load an image with opencv. Everything is working properly but it doesn't show me the image. Code what I usin is here:
#include
#include
#include
using namespace cv;
using namespace std;
int main( int argc, const char** argv )
{
IplImage *img = cvLoadImage("D:/C++/ MGC.JPG");
cvNamedWindow("MyWindow", 1); //create a window with the name "MyWindow"
cvMoveWindow("MyWindow", 100, 100);
cvShowImage("MyWindow", img);
cvWaitKey(0); //wait infinite time for a keypress
cvDestroyWindow("MyWindow"); //destroy the window with the name, "MyWindow"
return 0;
}
Is there a specific reason you chose to use the C interface? If not, you should be using the C++ interface
int main( int argc, const char** argv )
{
cv::Mat image = cv::imread("D:/C++/ MGC.JPG");
cv::namedWindow("MyWindow", 256);
cv::imshow("MyWindow", image );
cv::waitKey();
return 0;
}
I have configure an Openc CV include file path in Tool Setting, but it still gives warning in my code.
warning is :
Unresolved inclusion: <highgui.h>
my code is :
#include <cv.h>
#include <highgui.h>
using namespace cv;
int main()
{
Mat image;
image = imread( argv[1], 1 );
if( argc != 2 || !image.data )
{
printf( "No image data \n" );
return -1;
}
namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
imshow( "Display Image", image );
waitKey(0);
return 0;
}
You need to use a different include if you work with cv::Mat:
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
I'm trying to obtain a ROI from an image using VC++ and OpenCV.
I managed to display an image, get the coordinates of a point when I click on it, store these coordinates in a vector and draw lines between these points on my image.
Here is my code:
//Includes
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <stdio.h>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
using namespace std;
using namespace cv;
static int app;
static vector<Point2f> cont(6);
static Mat img = imread("C:/img.jpg",0);
void on_mouse(int, int, int, int, void* );
int main()
{
app = 0;
namedWindow("myWindow", CV_WINDOW_AUTOSIZE);
cvSetMouseCallback("myWindow", on_mouse, 0);
imshow("myWindow", img);
waitKey(0);
}
void on_mouse(int evt, int x, int y, int flags, void* param)
{
if(evt == CV_EVENT_LBUTTONDOWN)
{
Point pt(x,y);
if(app<6)
{
cont[app]=pt;
app++;
}
cout<<"Coordonnees du point pt : "<<x<<","<<y<<endl;
for (int i=0; i<6;i++)
{cout<<cont[i]<<endl;}
}
if(evt == CV_EVENT_RBUTTONDOWN)
{
for (int j=0;j<5;j++)
{
line(img,cont[(j)],cont[(j+1)],CV_RGB(255,0,0),2);
}
line(img,cont[(5)],cont[(0)],CV_RGB(255,0,0),2);
imshow("myWindow", img);
}
}
What I would like to obtain is a vector that contains the coordinates of all the points of the contour and ultimately a bianary matrix the size of my image that contains 0 if the pixel is not in the contour, else 1.
Thanks for your help.
Make single element vector< vector< Point> > and then use drawContours with CV_FILLED. Then you will have binary matrix you wanted.
I currently don't have IDE but code will be like following
vector< vector< Point> > contours;
contours.push_back(cont);//your cont
Mat output(img.rows,img.cols,CV_8UC1);//your img
drawContours(output, contours, 0, Scalar(1), CV_FILLED);//now you have binary image