I am capturing a video with 30fps, but when I process the video with openCV for AruCo marker detection I am loosing almost half of the frames. So for a 5 min video I expect 5x60x30 = 9000 frames but I am getting only about 4500 frames. I tried different resolution and fps while recording but the problem still persists. My code is as follows. I later want to sync the video with the audio recorded from the camera, so even if I could know the frames which are being lost can solve my problem. Any pointers or suggestions are welcome.
#include "opencv2\core.hpp"
#include "opencv2\imgcodecs.hpp"
#include "opencv2\imgproc.hpp"
#include "opencv2\highgui.hpp"
#include "opencv2\aruco.hpp"
#include "opencv2\calib3d.hpp"
#include <time.h>
#include <sstream>
#include <iostream>
#include <fstream>
#include "stdafx.h"
using namespace std;
using namespace cv;
#define _CRT_SECURE_NO_WARNINGS 1
int startWebcamMonitoring() //(const Mat& cameraMatrix, const Mat&
distanceCoefficients, float arucoSquareDimensions)
{
Mat frame4;
Scalar_<double> borderColor, borderColor2, borderColor3;
vector<int> markerIds;
vector < vector<Point2f>> markerCorners, rejectedCandidates ;
aruco::DetectorParameters parameters;
Ptr<aruco::Dictionary> makerDiktionary = aruco::getPredefinedDictionary(aruco::PREDEFINED_DICTIONARY_NAME::DICT_4X4_50);
VideoCapture cap("sample.mp4");
double fps = cap.get(CV_CAP_PROP_FPS);
cout << "Frames per second : " << fps << endl;
while (true)
{
cap >> sample;
if (!cap.read(frame4))
break;
aruco::detectMarkers(frame4, makerDiktionary, markerCorners, markerIds);
aruco::drawDetectedMarkers(frame4, markerCorners, markerIds, borderColor);
aruco::estimatePoseSingleMarkers(markerCorners, arucoSquareDimension,
cameraMatrix, distanceCoefficients, rotationVectors, translationVectors);
Mat rotationMatrix
for (int i = 0; i < markerIds.size(); i++)
{
aruco::drawAxis(frame4, cameraMatrix, distanceCoefficients, rotationVectors[i], translationVectors[i], 0.01f);
Rodrigues(rotationVectors[i], rotationMatrix);
time_t current = time(0);
cout << " Translation " << translationVectors[i] << " ID" << markerIds[i] << " Euler angles " << 180 / 3.1415*rotationMatrixToEulerAngles(rotationMatrix) << "current time " << ctime(¤t) << endl;
}
freopen("output_sample", "a", stdout);
imshow("recording", frame4);
if (waitKey(30) >= 0) break;
}
The problem is:
cap >> sample;
if (!cap.read(frame4))
break;
the program is reading a frame from source twice in every iteration.
You should remove the cap >> sample; line and it will be fine.
Related
I am using an ethernet camera in opencv but I repeatedly get the following warning message when I run my program.
[rtp # 0x1a9c720] Received packet without a start chunk; dropping frame.
I think the problem might be with the rtp url I am using:
vcap.open("rtp://192.168.40.90:50004/");
I'm not even sure if I should be using rtp or something else.
#include "opencv2/opencv.hpp"
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char *argv[])
{
VideoCapture vcap;
vcap.open("rtp://192.168.40.90:50004/"); // open IP cam
int numberOfFrames = 0;
for(;;)
{
Mat frame;
vcap >> frame;
cout << "number of frames = " << ++numberOfFrames << endl;
imshow( "display", frame );
char c = (char)waitKey(1);
if( c == 27 ) break;
}
vcap.release();
return 0;
}
I am trying to do Frame subtraction in a video.Steps I am following
Get a image , convert it into grayscale.
Subtract it from previous frame grayscale.
All I see in diff2(and diff also) a complete black image.One observation I made is that pixel value of gray1 and gray2 become equal.
My code
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/objdetect/objdetect.hpp"
#include <opencv2/video/background_segm.hpp>
#include <iostream>
using namespace cv;
using namespace std;
RNG rng(12345);
int main( int argc, const char** argv )
{
VideoCapture cap(0);
if ( !cap.isOpened() )
{
cout << "Cannot open the web cam" << endl;
return -1;
}
Mat img1,img2,diff,gray1,gray2,diff2;
bool bSuccess = cap.read(img1); // read a new frame from video
if (!bSuccess) //if not success, break loop
{
cout << "Cannot read a frame from video stream" << endl;
return -1;
}
cvtColor( img1,gray1, CV_BGR2GRAY );
while (true)
{
bSuccess = cap.read(img2); // read a new frame from video
if (!bSuccess) //if not success, break loop
{
cout << "Cannot read a frame from video stream" << endl;
break;
}
cvtColor( img2,gray2, CV_BGR2GRAY );
absdiff(gray2,gray1,diff);
threshold(diff, diff2, 150, 255, CV_THRESH_BINARY);
cout<<gray2.at<uchar>(100,200) <<endl;
cout<<gray1.at<uchar>(100,200) <<endl;
gray1=gray2;
imshow("1",gray1);
imshow("2",diff2);
if (waitKey(1000) == 27) //wait for 'esc' key press for 30ms. If 'esc' key is pressed, break loop
{
cout << "esc key is pressed by user" << endl;
break;
}
}
return -1;
}
please try this code. It looks like you're overwriting gray1 so that gray1 and gray2 use the very same data memory positions.
You could either use gray1=gray2.clone(); instead or use some real "swapping" of the buffers instead of overwriting. My code should perform a simple buffer swapping and has some comments about the problem.
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/objdetect/objdetect.hpp"
#include <opencv2/video/background_segm.hpp>
#include <iostream>
using namespace cv;
using namespace std;
RNG rng(12345);
int main( int argc, const char** argv )
{
VideoCapture cap(0);
if ( !cap.isOpened() )
{
cout << "Cannot open the web cam" << endl;
return -1;
}
Mat img1,img2,diff,gray1,gray2,diff2;
Mat tmp; // used to swap the buffers
bool bSuccess = cap.read(img1); // read a new frame from video
if (!bSuccess) //if not success, break loop
{
cout << "Cannot read a frame from video stream" << endl;
return -1;
}
// this will allocate memory of gray1 if not allocated yet
cvtColor( img1,gray1, CV_BGR2GRAY );
while (true)
{
bSuccess = cap.read(img2); // read a new frame from video
if (!bSuccess) //if not success, break loop
{
cout << "Cannot read a frame from video stream" << endl;
break;
}
// memory for gray2 won't be allocated if it is present already => if gray2 and gray1 use the same data memory, you'll overwrite gray1's pixels here and obviously gray1 and gray2 will have the same pixel values then
cvtColor( img2,gray2, CV_BGR2GRAY );
absdiff(gray2,gray1,diff);
threshold(diff, diff2, 150, 255, CV_THRESH_BINARY);
cout<<gray2.at<uchar>(100,200) <<endl;
cout<<gray1.at<uchar>(100,200) <<endl;
// don't lose the memory of gray1
tmp = gray1;
// this means gray1 and gray2 will use the same data memory location
gray1=gray2;
// give gray2 a new data memory location. Since previous gray1 memory is still present but wont be used anymore, use it here.
gray2=tmp;
imshow("1",gray1);
imshow("2",diff2);
if (waitKey(1000) == 27) //wait for 'esc' key press for 30ms. If 'esc' key is pressed, break loop
{
cout << "esc key is pressed by user" << endl;
break;
}
}
return -1;
}
in addition, a thres difference threshold of 150 might be very high for common tasks, but it might be ok for your special task. Typical difference values/thresholds in background subtraction for foreground extraction are around 20 to 30 from my experience, but at the end it depends on your task/problem/domain.
I am using OpenCV on an embedded target board (FriendlyARM mini6410, processor arm 1176 running linux kernel 2.6.38).
I compiled OpenCV 2.4.4 library using toolchain provided for the board, found in the ftp (pls see the website of FriendlyARM). I disabled GTK, ffmpeg and enable v4l. The library is compiled successfully.
Then I write code:
#include <opencv.hpp>
#include <highgui/highgui.hpp>
#include <imgproc/imgproc.hpp>
#include <iostream>
#include <stdio.h>
using namespace cv;
using namespace std;
int main()
{
int i;
cout << "initialise" << endl;
IplImage* img=0;
cout << "capturing ..." << endl;
CvCapture* capture = cvCaptureFromCAM(2);
cout << "get here" << endl;
if(!capture){
cout << "not capture" << endl;
return -1;
}
cout << "captured" << endl;
img=cvQueryFrame(capture);
IplImage* img1 = cvCreateImage(cvGetSize(img),8,3);
// cvCvtColor(img,img1,CV_RGB2GRAY);
cvCopy(img, img1);
cvSaveImage("cam_snap.jpg",img1);
cvReleaseImage( &img1 );
cvReleaseImage( &img );
cvReleaseCapture( &capture );
cout << "exit" << endl;
return 0;
}
The code is built successfully. I run the .elf executable in the target board, connected to camera (PS3 eye), but the resulting image looks like a broken television (noise-like):
While in my host, the resulting image is as expected (scene in front of camera). Can you provide me suggestion as to what went wrong or where should I start on debugging?
You should check your depth and channels. It is probably a matter of alignement, moreover be careful your image is probably in BGR and not in RGB.
And you should use cv::Mat instead of IplImage in C++ and VideoCapture instead of CVCapture.
This sample of code should work. (Not tested on the same arch as your)
#include <opencv.hpp>
#include <highgui/highgui.hpp>
#include <imgproc/imgproc.hpp>
#include <iostream>
#include <stdio.h>
using namespace cv;
using namespace std;
int main()
{
VideoCapture capture = cv::VideoCapture(0);
cout << "get here" << endl;
if(!capture.isOpened()) // check if we succeeded
return -1;
cout << "captured" << endl;
Mat img;
capture >> img;
imwrite("./test.png", img);
capture.release();
cout << "exit" << endl;
return 0;
}
Hope it helped.
Okay, confirmed. mini 6410 runs USB 1.0, and ps3 eye needs USB 2.0. I tried the program using standard webcam (chinese product, itech pc camera), works wonderfully. Saved image is showing scene in front of camera
I am trying to detect objects with cvblob. Somehow, my code only marks the white objects. How to mark objects of other colors, like a can of beer or a bottle of water.
Here is my code:
#include "highgui.h"
#include "cv.h"
#include "cvaux.h"
#include "iostream"
#include <stdio.h>
#include <ctype.h>
#include <cvblob.h>
using namespace cv;
using namespace std;
using namespace cvb;
int main(int argc, char** argv) {
CvTracks tracks;
cvNamedWindow("frame", CV_WINDOW_AUTOSIZE);
cvMoveWindow("frame", 50, 100);
CvCapture* capture;
IplImage* frame = 0;
capture = cvCreateCameraCapture( 0 ); //capture frames from cam on index 0: /dev/video0/
if (!capture) {
return -1;
}
cvSetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH, 320);
cvSetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT, 240);
frame = cvQueryFrame(capture);
while(frame) {
IplImage *gray = cvCreateImage(cvGetSize(frame), IPL_DEPTH_8U, 1);
cvCvtColor(frame, gray, CV_BGR2GRAY);
cvThreshold(gray, gray, 150, 255, CV_THRESH_BINARY);
IplImage *labelImg=cvCreateImage(cvGetSize(gray), IPL_DEPTH_LABEL, 1);
CvBlobs blobs;
unsigned int result=cvLabel(gray, labelImg, blobs);
cvFilterByArea(blobs, 500, 1000000);
// cvRenderBlobs(labelImg, blobs, frame, frame, CV_BLOB_RENDER_BOUNDING_BOX);
cvRenderBlobs(labelImg, blobs, frame, frame, CV_BLOB_RENDER_CENTROID);
cvUpdateTracks(blobs, tracks, 200., 5);
cvRenderTracks(tracks, frame, frame, CV_TRACK_RENDER_ID|CV_TRACK_RENDER_BOUNDING_BOX);
for (CvBlobs::const_iterator it=blobs.begin(); it!=blobs.end(); ++it) {
cout << "Blob #" << it->second->label << ": Area=" << it->second->area << ", Centroid=(" << it->second->centroid.x << ", " << it->second->centroid.y << ")" << endl;
}
cvShowImage("frame", frame);
cout << "----------------------------" << endl;
frame = cvQueryFrame(capture);
char c = cvWaitKey(10);
if(c==27)
break;
}
}
Any tip is appreciated.
Milo
That's the option by default and you cannot change it if you don't change the source code in cvblob library.
If you really want to change this is so easy, you can create a copy of the same method adding a new input var like CvScalar to select output color. It's so easy.
The method cvRenderBlob will be in cvcontour.cpp.
I've been made many improvement in cvblob library and in next months I will push it to the creator.
Try adding:
"cvInRangeS(hsvframe,cvScalar(23,41,133),cvScalar(40,150,255),threshy);//for yellow"
Before Filtering the blobs. Its a range of HSV(instead of RGB) values that defines the threshold of the desire color.
Hope it helps.
As the CPU based SURF in opencv was very slow for realtime application, we decided to use GPU_SURF, after setting up the opencv_gpu we made the following code:
#include <iostream>
#include <iomanip>
#include <windows.h>
#include "opencv2/contrib/contrib.hpp"
#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/gpu/gpu.hpp"
#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/core/types_c.h"
using namespace std;
using namespace cv;
using namespace cv::gpu;
void help()
{
cout << "\nThis program demonstrates using SURF_GPU features detector, descriptor extractor and BruteForceMatcher_GPU" << endl;
cout << "\nUsage:\n\tmatcher_simple_gpu <image1> <image2>" << endl;
}
int main(int argc, char* argv[])
{
GpuMat img1(imread("C:\\OpenCV2.3\\opencv2.3\\bin\\Debug\\tsucuba_left.png", CV_LOAD_IMAGE_GRAYSCALE));
SURF_GPU surf;
// detecting keypoints & computing descriptors
GpuMat keypoints1GPU, keypoints2GPU;
GpuMat descriptors1GPU, descriptors2GPU;
surf(img1, GpuMat(), keypoints1GPU, descriptors1GPU);
cout << "FOUND " << keypoints1GPU.cols << " keypoints on first image" << endl;
//cout << "FOUND " << keypoints2GPU.cols << " keypoints on second image" << endl;
CvCapture* capture = cvCreateCameraCapture(0);
int frame_width = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH);
int frame_height = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT);
cout<<"frames done\n";
cv::gpu::GpuMat frame_gpu = cv::gpu::GpuMat(frame_width, frame_height, CV_8UC3);
cv::gpu::GpuMat frame_gpu_cvt = cv::gpu::GpuMat(frame_width, frame_height, CV_8UC1);
cout<<"gpu frmes loaded\n";
//Sleep(200);
while(cvGrabFrame(capture))
{
IplImage* frame;
frame =cvQueryFrame(capture);
CvMat* image=0;
image = cvCreateMat(frame->height, frame->width, CV_8UC1);
frame_gpu.upload(image);
cout<<"frame uploaded\n";
cvtColor(frame_gpu,frame_gpu_cvt,CV_RGB2GRAY);
cout<<"color done\n";
surf(frame_gpu_cvt, GpuMat(), keypoints2GPU, descriptors2GPU);
// matching descriptors
BruteForceMatcher_GPU< L2<float> > matcher;
GpuMat trainIdx, distance;
matcher.matchSingle(descriptors1GPU, descriptors2GPU, trainIdx, distance);
// downloading results
vector<KeyPoint> keypoints1, keypoints2;
vector<float> descriptors1, descriptors2;
vector<DMatch> matches;
surf.downloadKeypoints(keypoints1GPU, keypoints1);
surf.downloadKeypoints(keypoints2GPU, keypoints2);
surf.downloadDescriptors(descriptors1GPU, descriptors1);
surf.downloadDescriptors(descriptors2GPU, descriptors2);
BruteForceMatcher_GPU< L2<float> >::matchDownload(trainIdx, distance, matches);
// drawing the results
Mat img_matches;
drawMatches(img1, keypoints1, frame_gpu, keypoints2, matches, img_matches);
namedWindow("matches", 0);
imshow("matches", img_matches);
//waitKey(0);
}
return 0;
}
The error that comes on executing it is:
OpenCV Error: Assertion failed (scn == 3 || scn == 4) in unknown function, file
..\..\..\opencv_2.3\opencv\modules\gpu\src\color.cpp, line 186
It is due to the line:
cvtColor(frame_gpu,frame_gpu_cvt,CV_RGB2GRAY);
There maybe other errors, can someone please help us out on this one.
scn is the number of channels in the first argument to cvtColor. Converting from RGB to GRAY requires that the first argument has three or four channels. The line frame_gpu.upload(image); is converting frame_gpu to one channel since image has one channel. It looks like you can skip the call to cvtColor and just call SURF directly on frame_gpu.