Uncaught exception in processFrame

[kalwalt]

As said in #10 i get sometimes this error:

__resumeException WebARKit.js:2

  $emscripten::internal::MethodInvoker<void (WebARKit::*)(emscripten::val, ColorSpace), void, WebARKit*, emscripten::val, ColorSpace>::invoke(void (WebARKit::* const&)(emscripten::val, ColorSpace), WebARKit*, emscripten::_EM_VAL*, ColorSpace) 00d78de6:0x12cf0
  WebARKit$processFrame VM21:10
  value WebARKit.js:2
  value WebARKit.js:2
  processFrame  worker.js:53
  self.onmessage

Note that this happens only on Mobile device.

[kalwalt]

with commit 7c4f5b2 i get now:

a	@	WebARKit.js:2
	$cv::error(int, std::__2::basic_string<char, std::__2::char_traits, std::__2::allocator> const&, char const*, char const*, int)	@
	$cv::(anonymous namespace)::SparsePyrLKOpticalFlowImpl::calc(cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputOutputArray const&, cv::_OutputArray const&, cv::_OutputArray const&)	@
	$webarkit::WebARKitAkazeTracker::track(cv::Mat&)	@
	$webarkit::WebARKitOrbTracker::processFrame(cv::Mat&)	@
	$webarkit::WebARKitAkazeTracker::processFrameData(unsigned char*, unsigned long, unsigned long, webarkit::ColorSpace)	@
	$WebARKit::processFrame(emscripten::val, webarkit::ColorSpace)	@
	$emscripten::internal::MethodInvoker<void (WebARKit::)(emscripten::val, webarkit::ColorSpace), void, WebARKit, emscripten::val, webarkit::ColorSpace>::invoke(void (WebARKit::* const&)(emscripten::val, webarkit::ColorSpace), WebARKit*, emscripten::_EM_VAL*, webarkit::ColorSpace)	@
	WebARKit$processFrame	@
	value	@
	value	@
	processFrame	@
	self.onmessage	@



I think i have to change the initialization of the trackers. The issue arise because i create two trackers with unique_ptr's? or should i create only one m_tracker (instead of m_akaze_tracker and m_orb_tracker) and instantiate the orb or akaze on demand?

[kalwalt]

i tested removing the m_orb_tracker and all related code and seems that the uncaught error does not show anymore. I will try to change the code in accord of this in dedicated PR.

[kalwalt]

This issue should be fixed with #16