rtabmap/corelib/src/MarkerDetector.cpp

/*
Copyright (c) 2010-2019, Mathieu Labbe - IntRoLab - Universite de Sherbrooke
All rights reserved.

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      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

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*/

#include <rtabmap/core/MarkerDetector.h>
#include <rtabmap/core/util2d.h>
#include <rtabmap/utilite/ULogger.h>

namespace rtabmap {

MarkerDetector::MarkerDetector(const ParametersMap & parameters)
{
#ifdef HAVE_OPENCV_ARUCO
	markerLength_ = Parameters::defaultMarkerLength();
	maxDepthError_ = Parameters::defaultMarkerMaxDepthError();
	maxRange_ = Parameters::defaultMarkerMaxRange();
	minRange_ = Parameters::defaultMarkerMinRange();
	dictionaryId_ = Parameters::defaultMarkerDictionary();
#if CV_MAJOR_VERSION > 4 || (CV_MAJOR_VERSION == 4 && CV_MINOR_VERSION >= 7)
    detectorParams_.reset(new cv::aruco::DetectorParameters());
#elif CV_MAJOR_VERSION > 3 || (CV_MAJOR_VERSION == 3 && CV_MINOR_VERSION >=2)
	detectorParams_ = cv::aruco::DetectorParameters::create();
#else
	detectorParams_.reset(new cv::aruco::DetectorParameters());
#endif
#if CV_MAJOR_VERSION > 4 || (CV_MAJOR_VERSION == 4 && CV_MINOR_VERSION >= 7)
    detectorParams_->cornerRefinementMethod = (cv::aruco::CornerRefineMethod) Parameters::defaultMarkerCornerRefinementMethod();
#elif CV_MAJOR_VERSION > 3 || (CV_MAJOR_VERSION == 3 && CV_MINOR_VERSION >=3)
	detectorParams_->cornerRefinementMethod = Parameters::defaultMarkerCornerRefinementMethod();
#else
	detectorParams_->doCornerRefinement = Parameters::defaultMarkerCornerRefinementMethod()!=0;
#endif
	parseParameters(parameters);
#endif
}

MarkerDetector::~MarkerDetector() {

}

void MarkerDetector::parseParameters(const ParametersMap & parameters)
{
#ifdef HAVE_OPENCV_ARUCO
	detectorParams_->adaptiveThreshWinSizeMin = 3;
	detectorParams_->adaptiveThreshWinSizeMax = 23;
	detectorParams_->adaptiveThreshWinSizeStep = 10;
	detectorParams_->adaptiveThreshConstant = 7;
	detectorParams_->minMarkerPerimeterRate = 0.03;
	detectorParams_->maxMarkerPerimeterRate = 4.0;
	detectorParams_->polygonalApproxAccuracyRate = 0.03;
	detectorParams_->minCornerDistanceRate = 0.05;
	detectorParams_->minDistanceToBorder = 3;
	detectorParams_->minMarkerDistanceRate = 0.05;
#if CV_MAJOR_VERSION > 4 || (CV_MAJOR_VERSION == 4 && CV_MINOR_VERSION >= 7)
    int cornerRefinementMethod;
    Parameters::parse(parameters, Parameters::kMarkerCornerRefinementMethod(), cornerRefinementMethod);
    detectorParams_->cornerRefinementMethod = (cv::aruco::CornerRefineMethod)cornerRefinementMethod;
#elif CV_MAJOR_VERSION > 3 || (CV_MAJOR_VERSION == 3 && CV_MINOR_VERSION >=3)
	Parameters::parse(parameters, Parameters::kMarkerCornerRefinementMethod(), detectorParams_->cornerRefinementMethod);
#else
	int doCornerRefinement = detectorParams_->doCornerRefinement?1:0;
	Parameters::parse(parameters, Parameters::kMarkerCornerRefinementMethod(), doCornerRefinement);
	detectorParams_->doCornerRefinement = doCornerRefinement!=0;
#endif
	detectorParams_->cornerRefinementWinSize = 5;
	detectorParams_->cornerRefinementMaxIterations = 30;
	detectorParams_->cornerRefinementMinAccuracy = 0.1;
	detectorParams_->markerBorderBits = 1;
	detectorParams_->perspectiveRemovePixelPerCell = 4;
	detectorParams_->perspectiveRemoveIgnoredMarginPerCell = 0.13;
	detectorParams_->maxErroneousBitsInBorderRate = 0.35;
	detectorParams_->minOtsuStdDev = 5.0;
	detectorParams_->errorCorrectionRate = 0.6;

	Parameters::parse(parameters, Parameters::kMarkerLength(), markerLength_);
	Parameters::parse(parameters, Parameters::kMarkerMaxDepthError(), maxDepthError_);
	Parameters::parse(parameters, Parameters::kMarkerMaxRange(), maxRange_);
	Parameters::parse(parameters, Parameters::kMarkerMinRange(), minRange_);
	Parameters::parse(parameters, Parameters::kMarkerDictionary(), dictionaryId_);
#if CV_MAJOR_VERSION < 3 || (CV_MAJOR_VERSION == 3 && (CV_MINOR_VERSION <4 || (CV_MINOR_VERSION ==4 && CV_SUBMINOR_VERSION<2)))
	if(dictionaryId_ >= 17)
	{
		UERROR("Cannot set AprilTag dictionary. OpenCV version should be at least 3.4.2, "
				"current version is %s. Setting %s to default (%d)",
				CV_VERSION,
				Parameters::kMarkerDictionary().c_str(),
				Parameters::defaultMarkerDictionary());
		dictionaryId_ = Parameters::defaultMarkerDictionary();
	}
#endif
#if CV_MAJOR_VERSION > 4 || (CV_MAJOR_VERSION == 4 && CV_MINOR_VERSION >= 7)
    dictionary_.reset(new cv::aruco::Dictionary());
    *dictionary_ = cv::aruco::getPredefinedDictionary(cv::aruco::PredefinedDictionaryType(dictionaryId_));
#elif CV_MAJOR_VERSION > 3 || (CV_MAJOR_VERSION == 3 && CV_MINOR_VERSION >=2)
	dictionary_ = cv::aruco::getPredefinedDictionary(cv::aruco::PREDEFINED_DICTIONARY_NAME(dictionaryId_));
#else
	dictionary_.reset(new cv::aruco::Dictionary());
	*dictionary_ = cv::aruco::getPredefinedDictionary(cv::aruco::PREDEFINED_DICTIONARY_NAME(dictionaryId_));
#endif
#endif
}

std::map<int, Transform> MarkerDetector::detect(const cv::Mat & image, const CameraModel & model, const cv::Mat & depth, float * markerLengthOut, cv::Mat * imageWithDetections)
{
    std::map<int, Transform> detections;
    std::map<int, MarkerInfo> infos = detect(image, model, depth, std::map<int, float>(), imageWithDetections);
    
    for(std::map<int, MarkerInfo>::iterator iter=infos.begin(); iter!=infos.end(); ++iter)
    {
        detections.insert(std::make_pair(iter->first, iter->second.pose()));
        
        if(markerLengthOut)
        {
            *markerLengthOut = iter->second.length();
        }
    }
    
    return detections;
}

std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
                           const std::vector<CameraModel> & models,
                           const cv::Mat & depth,
                           const std::map<int, float> & markerLengths,
                           cv::Mat * imageWithDetections)
{
	UASSERT(!models.empty() && !image.empty());
	UASSERT(int((image.cols/models.size())*models.size()) == image.cols);
	UASSERT(int((depth.cols/models.size())*models.size()) == depth.cols);
	int subRGBWidth = image.cols/models.size();
	int subDepthWidth = depth.cols/models.size();

	std::map<int, MarkerInfo> allInfo;
	for(size_t i=0; i<models.size(); ++i)
	{
		cv::Mat subImage(image, cv::Rect(subRGBWidth*i, 0, subRGBWidth, image.rows));
		cv::Mat subDepth;
		if(!depth.empty())
			subDepth = cv::Mat(depth, cv::Rect(subDepthWidth*i, 0, subDepthWidth, depth.rows));
		CameraModel model = models[i];
		cv::Mat subImageWithDetections;
		std::map<int, MarkerInfo> subInfo = detect(subImage, model, subDepth, markerLengths, imageWithDetections?&subImageWithDetections:0);
		if(ULogger::level() >= ULogger::kWarning)
		{
			for(std::map<int, MarkerInfo>::iterator iter=subInfo.begin(); iter!=subInfo.end(); ++iter)
			{
				std::pair<std::map<int, MarkerInfo>::iterator, bool> inserted = allInfo.insert(*iter);
				if(!inserted.second)
				{
					UWARN("Marker %d already added by another camera, ignoring detection from camera %d", iter->first, i);
				}
			}
		}
		else
		{
			allInfo.insert(subInfo.begin(), subInfo.end());
		}
		if(imageWithDetections)
		{
			if(i==0)
			{
				*imageWithDetections = cv::Mat(image.size(), subImageWithDetections.type());
			}
			if(!subImageWithDetections.empty())
			{
				subImageWithDetections.copyTo(cv::Mat(*imageWithDetections, cv::Rect(subRGBWidth*i, 0, subRGBWidth, image.rows)));
			}
		}
	}
	return allInfo;
}

std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
                           const CameraModel & model,
                           const cv::Mat & depth,
                           const std::map<int, float> & markerLengths,
                           cv::Mat * imageWithDetections)
{
	if(!image.empty() && image.cols != model.imageWidth())
	{
		UERROR("This method cannot handle multi-camera marker detection, use the other function version supporting it.");
		return std::map<int, MarkerInfo>();
	}

    std::map<int, MarkerInfo> detections;

#ifdef HAVE_OPENCV_ARUCO

	std::vector< int > ids;
	std::vector< std::vector< cv::Point2f > > corners, rejected;
	std::vector< cv::Vec3d > rvecs, tvecs;

	// detect markers and estimate pose
#if CV_MAJOR_VERSION > 3 || (CV_MAJOR_VERSION == 3 && CV_MINOR_VERSION >=2)
	cv::aruco::detectMarkers(image, dictionary_, corners, ids, detectorParams_, rejected);
#else
	cv::aruco::detectMarkers(image, *dictionary_, corners, ids, *detectorParams_, rejected);
#endif
	UDEBUG("Markers detected=%d rejected=%d", (int)ids.size(), (int)rejected.size());
	if(ids.size() > 0)
	{
		float rgbToDepthFactorX = 1.0f;
		float rgbToDepthFactorY = 1.0f;
		if(!depth.empty())
		{
			rgbToDepthFactorX = 1.0f/(model.imageWidth()>0?float(model.imageWidth())/float(depth.cols):1.0f);
			rgbToDepthFactorY = 1.0f/(model.imageHeight()>0?float(model.imageHeight())/float(depth.rows):1.0f);
		}
        else if(markerLength_ == 0)
        {
            if(depth.empty())
            {
                UERROR("Depth image is empty, please set %s parameter to non-null.", Parameters::kMarkerLength().c_str());
                return detections;
            }
        }

		cv::aruco::estimatePoseSingleMarkers(corners, markerLength_<=0.0?1.0f:markerLength_, model.K(), model.D(), rvecs, tvecs);
		std::vector<float> scales;
		for(size_t i=0; i<ids.size(); ++i)
		{
            float length = 0.0f;
            std::map<int, float>::const_iterator findIter = markerLengths.find(ids[i]);
            if(!depth.empty() && (markerLength_ == 0 || (markerLength_<0 && findIter==markerLengths.end())))
			{
                float d = util2d::getDepth(depth, (corners[i][0].x + (corners[i][2].x-corners[i][0].x)/2.0f)*rgbToDepthFactorX, (corners[i][0].y + (corners[i][2].y-corners[i][0].y)/2.0f)*rgbToDepthFactorY, true, 0.02f, true);
				float d1 = util2d::getDepth(depth, corners[i][0].x*rgbToDepthFactorX, corners[i][0].y*rgbToDepthFactorY, true, 0.02f, true);
				float d2 = util2d::getDepth(depth, corners[i][1].x*rgbToDepthFactorX, corners[i][1].y*rgbToDepthFactorY, true, 0.02f, true);
				float d3 = util2d::getDepth(depth, corners[i][2].x*rgbToDepthFactorX, corners[i][2].y*rgbToDepthFactorY, true, 0.02f, true);
				float d4 = util2d::getDepth(depth, corners[i][3].x*rgbToDepthFactorX, corners[i][3].y*rgbToDepthFactorY, true, 0.02f, true);
				// Accept measurement only if all 4 depth values are valid and
				// they are at the same depth (camera should be perpendicular to marker for
				// best depth estimation)
				if(d>0 && d1>0 && d2>0 && d3>0 && d4>0)
				{
                    float scale = d/tvecs[i].val[2];
                    
					if( fabs(d-d1) < maxDepthError_ &&
                        fabs(d-d2) < maxDepthError_ &&
						fabs(d-d3) < maxDepthError_ &&
						fabs(d-d4) < maxDepthError_)
					{
                        length = scale;
						scales.push_back(length);
						tvecs[i] *= scales.back();
						UWARN("Automatic marker length estimation: id=%d depth=%fm length=%fm", ids[i], d, scales.back());
					}
					else
					{
						UWARN("The four marker's corners should be "
							  "perpendicular to camera to estimate correctly "
							  "the marker's length. Errors: %f, %f, %f > %fm (%s). Four corners: %f %f %f %f (middle=%f). "
							  "Parameter %s can be set to non-null to skip automatic "
							  "marker length estimation. Detections are ignored.",
							  fabs(d1-d2), fabs(d1-d3), fabs(d1-d4), maxDepthError_, Parameters::kMarkerMaxDepthError().c_str(),
							  d1, d2, d3, d4, d,
								Parameters::kMarkerLength().c_str());
                        continue;
					}
				}
				else
				{
					UWARN("Some depth values (%f,%f,%f,%f, middle=%f) cannot be detected on the "
						  "marker's corners, cannot initialize marker length. "
						  "Parameter %s can be set to non-null to skip automatic "
						  "marker length estimation. Detections are ignored.",
						  d1,d2,d3,d4,d,
						  Parameters::kMarkerLength().c_str());
                    continue;
				}
			}
            else if(markerLength_ < 0)
            {
                if(findIter!=markerLengths.end())
                {
                    length = findIter->second;
                    tvecs[i] *= length;
                }
                else
                {
                    UWARN("Cannot find marker length for marker %d, ignoring this marker (count=%d)", ids[i], (int)markerLengths.size());
                    continue;
                }
            }
            else if(markerLength_ > 0)
            {
                length = markerLength_;
            }
            else
            {
                continue;
            }

			// Limit the detection range to be between the min / max range.
			// If the ranges are -1, allow any detection within that direction.
			if((maxRange_ <= 0 || tvecs[i].val[2] < maxRange_) &&
				(minRange_ <= 0 || tvecs[i].val[2] > minRange_))
			{
				cv::Mat R;
				cv::Rodrigues(rvecs[i], R);
				Transform t(R.at<double>(0,0), R.at<double>(0,1), R.at<double>(0,2), tvecs[i].val[0],
								 R.at<double>(1,0), R.at<double>(1,1), R.at<double>(1,2), tvecs[i].val[1],
								 R.at<double>(2,0), R.at<double>(2,1), R.at<double>(2,2), tvecs[i].val[2]);
				Transform pose = model.localTransform() * t;
				detections.insert(std::make_pair(ids[i], MarkerInfo(ids[i], length, pose)));
				UDEBUG("Marker %d detected in base_link: %s, optical_link=%s, local transform=%s", ids[i], pose.prettyPrint().c_str(), t.prettyPrint().c_str(), model.localTransform().prettyPrint().c_str());
			}
		}
		if(markerLength_ == 0 && !scales.empty())
		{
			float sum = 0.0f;
			float maxError = 0.0f;
			for(size_t i=0; i<scales.size(); ++i)
			{
				if(i>0)
				{
					float error = fabs(scales[i]-scales[0]);
					if(error > 0.001f)
					{
						UWARN("The marker's length detected between 2 of the "
							  "markers doesn't match (%fm vs %fm)."
							  "Parameter %s can be set to non-null to skip automatic "
							  "marker length estimation. Detections are ignored.",
							  scales[i], scales[0],
							  Parameters::kMarkerLength().c_str());
						detections.clear();
						return detections;
					}
					if(error > maxError)
					{
						maxError = error;
					}
				}
				sum += scales[i];
			}
			markerLength_ = sum/float(scales.size());
			UWARN("Final marker length estimated = %fm, max error=%fm (used for subsequent detections)", markerLength_, maxError);
		}
	}

	if(imageWithDetections)
	{
		if(image.channels()==1)
		{
			cv::cvtColor(image, *imageWithDetections, cv::COLOR_GRAY2BGR);
		}
		else
		{
			image.copyTo(*imageWithDetections);
		}
		if(!ids.empty())
		{
			cv::aruco::drawDetectedMarkers(*imageWithDetections, corners, ids);

			for(unsigned int i = 0; i < ids.size(); i++)
			{
                std::map<int, MarkerInfo>::iterator iter = detections.find(ids[i]);
                if(iter!=detections.end())
                {
#if CV_MAJOR_VERSION > 4 || (CV_MAJOR_VERSION == 4 && (CV_MINOR_VERSION >1 || (CV_MINOR_VERSION==1 && CV_PATCH_VERSION>=1)))
                    cv::drawFrameAxes(*imageWithDetections, model.K(), model.D(), rvecs[i], tvecs[i], iter->second.length() * 0.5f);
#else
                    cv::aruco::drawAxis(*imageWithDetections, model.K(), model.D(), rvecs[i], tvecs[i], iter->second.length() * 0.5f);
#endif
                }
			}
		}
	}

#else
	UERROR("RTAB-Map is not built with \"aruco\" module from OpenCV.");
#endif

	return detections;
}


} /* namespace rtabmap */