[EDIT] mutex with cap

src/computervision/ObjectDetection.cpp

@@ -27,7 +27,11 @@ namespace computervision
 	}
 
 	cv::Mat ObjectDetection::readCamera() {
+		videocapture::getMutex()->lock();
+
 		videocapture::getCap().read(img);
+
+		videocapture::getMutex()->unlock();
 		return img;
 	}
 
@@ -74,8 +78,10 @@ namespace computervision
 
 	void ObjectDetection::calculateDifference()
 	{
+		videocapture::getMutex()->lock();
 		videocapture::getCap().read(img);
 		videocapture::getCap().read(img2);
+		videocapture::getMutex()->unlock();
 
 		cv::cvtColor(img, imgGray, cv::COLOR_RGBA2GRAY);
 		cv::cvtColor(img2, img2Gray, cv::COLOR_RGBA2GRAY);

src/computervision/VideoCapture.cpp

@@ -1,11 +1,18 @@
 #include "VideoCapture.h"
+#include <mutex>
 
 namespace videocapture{
 	static cv::VideoCapture cap(1);
+	static std::mutex mtx;
 
 	cv::VideoCapture getCap() {
-		cap.release();
+		//cap.release();
 
 		return cap;
 	}
+
+	std::mutex* getMutex()
+	{
+		return &mtx;
+	}
 }

src/computervision/VideoCapture.h

@@ -2,7 +2,10 @@
 #include <opencv2/videoio.hpp>
 #include <opencv2/highgui.hpp>
 #include <opencv2/video.hpp>
+#include <mutex>
 
 namespace videocapture {
 	cv::VideoCapture getCap();
+	std::mutex* getMutex();
+
 }

src/computervision/async/async_arm_detection.cpp

@@ -23,17 +23,23 @@ namespace computervision
 		auto lambda = [](std::function<void(std::vector<Point>)> f, OpenPoseVideo op) {
 			std::cout << "STARTING THREAD LAMBDA" << std::endl;
 
+			videocapture::getMutex()->lock();
 			if (!videocapture::getCap().isOpened())
 			{
 				std::cout << "error opening video" << std::endl;
 				videocapture::getCap().open(1);
 				return;
 			}
+			videocapture::getMutex()->unlock();
 			Mat img;
 			while (true)
 			{
+				videocapture::getMutex()->lock();
+
 				videocapture::getCap().read(img);
 				imshow("image", img);
+
+				videocapture::getMutex()->unlock();
 				op.movementSkeleton(img, f);
 			}
 		};