Hello, I train the cascade classifier to detect letters, here is the code I'm running:
#include "opencv2/objdetect.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include
#include
using namespace std;
using namespace cv;
/** Function Headers */
void detectAndDisplay(Mat frame);
/** Global variables */
String letter_cascade_name = "C:\\opencv\\sources\\data\\haarcascades_GPU\\letters_cascade.xml";
CascadeClassifier letter_cascade;
String window_name = "Capture - letter detection";
/** @function main */
int main(void)
{
VideoCapture capture;
Mat frame;
//-- 1. Load the cascades
if (!letter_cascade.load(letter_cascade_name)) { printf("--(!)Error loading face cascade\n"); return -1; };
//-- 2. Read the video stream
capture.open(0);
if (!capture.isOpened()) { printf("--(!)Error opening video capture\n"); return -1; }
while (capture.read(frame))
{
if (frame.empty())
{
printf(" --(!) No captured frame -- Break!");
break;
}
//-- 3. Apply the classifier to the frame
detectAndDisplay(frame);
int c = waitKey(10);
if ((char)c == 27) { break; } // escape
}
return 0;
}
/** @function detectAndDisplay */
void detectAndDisplay(Mat frame)
{
std::vector letters;
Mat frame_gray;
cvtColor(frame, frame_gray, COLOR_BGR2GRAY);
equalizeHist(frame_gray, frame_gray);
//-- Detect faces
letter_cascade.detectMultiScale(frame_gray, letters, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));
for (size_t i = 0; i < letters.size(); i++)
{
Point center(letters[i].x + letters[i].width / 2, letters[i].y + letters[i].height / 2);
ellipse(frame, center, Size(letters[i].width / 2, letters[i].height / 2), 0, 0, 360, Scalar(255, 0, 255), 4, 8, 0);
}
//-- Show what you got
imshow(window_name, frame);
}
When I start the program, it opens my web cam but doesn't show the image (frames) and the detection but just a single blank window.
I noticed this line causes the problem:
letter_cascade.detectMultiScale(frame_gray, letters, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));
What should I do to make it show the captured frames and start detecting?
Thank you.
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