error LNK2019 while runing face detection in opencv using visual studio - c++

Question

I was trying on a code to detect faces from the image. I tried the following sample code from the net.
#include <opencv2/objdetect/objdetect.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
#include <stdio.h>
using namespace std;
using namespace cv;
int main(int argc, const char** argv)
{
//create the cascade classifier object used for the face detection
CascadeClassifier face_cascade;
//use the haarcascade_frontalface_alt.xml library
face_cascade.load("haarcascade_frontalface_alt.xml");
//setup video capture device and link it to the first capture device
VideoCapture captureDevice;
captureDevice.open(0);
//setup image files used in the capture process
Mat captureFrame;
Mat grayscaleFrame;
//create a window to present the results
namedWindow("outputCapture", 1);
//create a loop to capture and find faces
while (true)
{
//capture a new image frame
captureDevice >> captureFrame;
//convert captured image to gray scale and equalize
cvtColor(captureFrame, grayscaleFrame, CV_BGR2GRAY);
equalizeHist(grayscaleFrame, grayscaleFrame);
//create a vector array to store the face found
std::vector<Rect> faces;
//find faces and store them in the vector array
face_cascade.detectMultiScale(grayscaleFrame, faces, 1.1, 3, CV_HAAR_FIND_BIGGEST_OBJECT | CV_HAAR_SCALE_IMAGE, Size(30, 30));
//draw a rectangle for all found faces in the vector array on the original image
for (int i = 0; i < faces.size(); i++)
{
Point pt1(faces[i].x + faces[i].width, faces[i].y + faces[i].height);
Point pt2(faces[i].x, faces[i].y);
rectangle(captureFrame, pt1, pt2, cvScalar(0, 255, 0, 0), 1, 8, 0);
}
//print the output
imshow("outputCapture", captureFrame);
//pause for 33ms
waitKey(33);
}
return 0;
}
Currently i am getting this error :
Error 1 error LNK2019: unresolved external symbol "public: __cdecl cv::CascadeClassifier::CascadeClassifier(void)" (??0CascadeClassifier#cv##QEAA#XZ) referenced in function main
Need help in resolving the issue.

Answer 1

cv::CascadeClassifier::CascadeClassifier(void) constructor call doesn't seem to exist. Check openCV documentation here -
http://docs.opencv.org/modules/objdetect/doc/cascade_classification.html
Seems like a linking problem. Check if you have similar problems like here
http://answers.opencv.org/question/9421/cascade-classifier-for-eye-detection-errors-while-compiling/