detectMultiScale detects insane amount of faces [closed]
Hi,
This is my first attempt to detect faces with OpenCV but i am getting strange results. I am using the newest OpenCV files. but something is not right and i am getting detectMultiScale to fill the faces vector with 265290877 unusable entries. where most of them look like this [0] = {x=0 y=0 width=-1414812757 height = -1414812757}. so does any one know what i am doing wrong?
#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
if (!face_cascade.load("haarcascade_frontalface_alt.xml"))
{
printf("Unable to load classifier XML");
return 0;
}
//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;
captureFrame = imread("Test.png", IMREAD_COLOR);
if (captureFrame.empty()) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl;
return 0;
}
//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, 0 | 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;
}
Can you post your image as we can also do the test ?
yes good idea
here is the image i am using = http://www.r-junk.com/Data/OpenCV/Tes...
here is the VS debug view = http://www.r-junk.com/Data/OpenCV/out...
when using my webcam i was getting the same results
I tried your code with OpenCV 2.4.9 and everything is fine on my computer. With the following minimal code:
I have the output:
Well i just managed to rebuild 3.0 my self in visual studio changed the lib location and everything worked fine. so i am stumped why the pre-built libs doe not work with visual studio 2013. but i guess my problem is solved. i don't know if this is a but or not and don't really know if i need to report it.
Are you sure you used the correct directory (vc10 is for VS2010, vc11 is for VS2012 and vc12 is for VS2013) ? Did you try with the latest version: OpenCV 3.0 gold (2015/06/04) ?
Yea i was using the vc12\lib folder. it compiled just fine
I have the same problem - innumerable number of faces in face_cascade.detectMultiScale.
Visual Studio 2015 Community, C++, Windows 10, OpenCV 3.1, x64, tried both Debug and Releas. Source code like above.
I tried various combinations of the debug configurations: MT, MD, MDd I tried all of classifiers for faces: haarcascade_frontalcatface.xml, haarcascade_frontalface_alt.xml, haarcascade_frontalface_default.xml from opencv\build\etc\haarcascades
When I tried source line face_cascade.detectMultiScale(frame_gray, faces, 1.1, 3, 0 | CV_HAAR_SCALE_IMAGE, Size(30, 30)); the error access violation record appears (record or writing i do not shure because have a Russian interface)
Next I tried change Size(500,500), and when line pass but faces keeps billlllions of faces.
I rebuild 3.1.0 library and again has got a lot of faces on both my books (with Intel HD 4000 one and NVIDIA GeForce GT 425M another) captureFrame=640x480 ; type=16 faces.size()=18446743934142353947 after
capture >> frame; std::cout << "captureFrame=" << frame.cols << "x" << frame.rows << " ; type=" << frame.type() << std::endl;
What are we all doing wrong?