Assertion failed (!empty()) in cv::CascadeClassifier::detectMultiScale thrown at runtime
I am trying to do real-time face, nose and eyes detection the following is my code. The problem is that nose_cascade.detectMultiScale(faceROI, noses, 1.1, 2, 0 | CV_HAAR_SCALE_IMAGE, Size(30, 30));
statement generates run-time exception and I don't know the reason.
The exception is: Assertion failed (!empty()) in cv::CascadeClassifier::detectMultiScale
What is the problem can someone please tell me. I have the xml files in the right directories and the rest of the code is working fine except that particular line.
#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
using namespace std;
using namespace cv;
/** Function Headers */
void detectAndDisplay(Mat frame);
/** Global variables */
String face_cascade_name = "haarcascade_frontalface_alt.xml";
String eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
String nose_cascade_name = "haarcascade_mcs_nose.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;
CascadeClassifier nose_cascade;
string window_name = "Capture - Face detection";
RNG rng(12345);
/** @function main */
int main(int argc, const char** argv)
{
VideoCapture vcap(0);
if (!vcap.isOpened()) {
cout << "Error opening video stream" << endl;
return -1;
}
Mat frame;
//-- 1. Load the cascades
if (!face_cascade.load(face_cascade_name)) { printf("--(!)Error loading\n"); return -1; };
if (!eyes_cascade.load(eyes_cascade_name)) { printf("--(!)Error loading\n"); return -1; };
//-- 2. Read the video stream
while (true)
{
vcap >> frame;
//-- 3. Apply the classifier to the frame
if (!frame.empty())
{
detectAndDisplay(frame);
}
else
{
printf(" --(!) No captured frame -- Break!"); break;
}
int c = waitKey(10);
if ((char)c == 'c') { break; }
}
return 0;
}
/** @function detectAndDisplay */
void detectAndDisplay(Mat frame)
{
std::vector<Rect> faces;
Mat frame_gray;
cvtColor(frame, frame_gray, CV_BGR2GRAY);
equalizeHist(frame_gray, frame_gray);
//-- Detect faces
face_cascade.detectMultiScale(frame_gray, faces, 1.1, 2, 0 | CV_HAAR_SCALE_IMAGE, Size(30, 30));
for (size_t i = 0; i < faces.size(); i++)
{
Point center(faces[i].x + faces[i].width*0.5, faces[i].y + faces[i].height*0.5);
rectangle(frame, Point(faces[i].x, faces[i].y), Point(faces[i].x + faces[i].width, faces[i].y + faces[i].height), Scalar(255, 0, 0), 3, 8);
Mat faceROI = frame_gray(faces[i]);
vector<Rect> eyes;
vector<Rect> noses;
//-- In each face, detect eyes
eyes_cascade.detectMultiScale(faceROI, eyes, 1.1, 2, 0 | CV_HAAR_SCALE_IMAGE, Size(30, 30));
for (size_t j = 0; j < eyes.size(); j++)
{
Point center(faces[i].x + eyes[j].x + eyes[j].width*0.5, faces[i].y + eyes[j].y + eyes[j].height*0.5);
int radius = cvRound((eyes[j].width + eyes[j].height)*0.25);
circle(frame, center, radius, Scalar(255, 0, 0), 4, 8, 0);
}
nose_cascade.detectMultiScale(faceROI, noses, 1.1, 2, 0 | CV_HAAR_SCALE_IMAGE, Size(30, 30));
for (size_t j = 0; j < noses.size(); j++) {
Point center(faces[i].x + noses[j].x + noses[j].width*0.5, faces[i].y + noses[j].y + noses[j].height*0.5);
int radius = cvRound((noses[j].width + noses[j].height)*0.25);
circle(frame, center, radius, Scalar(0, 0, 255), 4, 8, 0);
}
}
//-- Show what you got
imshow(window_name, frame);
}
Looks like it cannot load the classifier file. Try to put the cascade files in the same folder than the executable or use absolute pathname.