Adding support for AprilTag v3 library

CMakeLists.txt

@@ -230,6 +230,7 @@ option(WITH_FASTCV        "Include FastCV support"               ON)
 option(WITH_OPENMP        "Include OpenMP support"               ON)
 option(WITH_OPENGV        "Include OpenGV support"               ON)
 option(BUILD_OPENGV       "Build OpenGV internally instead of using the system one" OFF)
+option(WITH_APRILTAG      "Include AprilTag support"             OFF)
 IF(MOBILE_BUILD)
 option(PCL_OMP            "With PCL OMP implementations"         OFF)
 ELSE()
@@ -866,6 +867,13 @@ IF(WITH_FASTCV)
     ENDIF(FastCV_FOUND)
 ENDIF(WITH_FASTCV)
 
+IF(WITH_APRILTAG)
+    FIND_PACKAGE(apriltag QUIET)
+    IF(apriltag_FOUND)
+       MESSAGE(STATUS "Found apriltag")
+    ENDIF(apriltag_FOUND)
+ENDIF(WITH_APRILTAG)
+
 IF(WITH_OPENGV OR okvis_FOUND)
    if(NOT BUILD_OPENGV)
       FIND_PACKAGE(opengv QUIET)
@@ -1066,6 +1074,9 @@ ENDIF(NOT Open3D_FOUND)
 IF(NOT FastCV_FOUND)
    SET(FASTCV "//")
 ENDIF(NOT FastCV_FOUND)
+IF(NOT apriltag_FOUND)
+   SET(APRILTAG "//")
+ENDIF(NOT apriltag_FOUND)
 IF(NOT opengv_FOUND OR NOT WITH_OPENGV)
    SET(OPENGV "//")
 ENDIF(NOT opengv_FOUND OR NOT WITH_OPENGV)
@@ -1571,6 +1582,14 @@ ELSE()
 MESSAGE(STATUS "  With FastCV               = NO (FastCV not found)")
 ENDIF()
 
+IF(apriltag_FOUND)
+MESSAGE(STATUS "  With AprilTag ${apriltag_VERSION}       = YES (License: BSD 2-Clause License)")
+ELSEIF(NOT WITH_APRILTAG)
+MESSAGE(STATUS "  With AprilTag             = NO (WITH_APRILTAG=OFF)")
+ELSE()
+MESSAGE(STATUS "  With AprilTag             = NO (apriltag not found)")
+ENDIF()
+
 IF(PDAL_FOUND)
 MESSAGE(STATUS "  With PDAL ${PDAL_VERSION}           = YES (License: BSD)")
 ELSEIF(NOT WITH_PDAL)

Version.h.in

@@ -93,6 +93,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 @TORCH@#define RTABMAP_TORCH
 @PYTHON@#define RTABMAP_PYTHON
 @MADGWICK@#define RTABMAP_MADGWICK
+@APRILTAG@#define RTABMAP_APRILTAG
 
 #include <pcl/pcl_config.h>
 

corelib/include/rtabmap/core/MarkerDetector.h

@@ -57,6 +57,12 @@ private:
 };
 
 class RTABMAP_CORE_EXPORT MarkerDetector {
+
+public:
+  enum Strategy {
+    kStrategyOpencv,
+    kStrategyApriltag
+  };
     
 public:
 	MarkerDetector(const ParametersMap & parameters = ParametersMap());
@@ -84,15 +90,18 @@ public:
 		    cv::Mat * imageWithDetections = 0);
 
 private:
-#ifdef HAVE_OPENCV_ARUCO
-	cv::Ptr<cv::aruco::DetectorParameters> detectorParams_;
-	float markerLength_;
+  Strategy strategy_;
+  float markerLength_;
 	float maxDepthError_;
 	float maxRange_;
 	float minRange_;
 	int dictionaryId_;
+#ifdef HAVE_OPENCV_ARUCO
+	cv::Ptr<cv::aruco::DetectorParameters> detectorParams_;
 	cv::Ptr<cv::aruco::Dictionary> dictionary_;
 #endif
+  void * apriltagLibDetector_;
+  void * apriltagLibFamily_;
 };
 
 } /* namespace rtabmap */

corelib/include/rtabmap/core/Parameters.h

@@ -917,6 +917,7 @@ class RTABMAP_CORE_EXPORT Parameters
     RTABMAP_PARAM(GridGlobal, ProbClampingMax,      float,  0.971,   "Probability clamping maximum (value between 0 and 1).");
     RTABMAP_PARAM(GridGlobal, FloodFillDepth,       unsigned int, 0, "Flood fill filter (0=disabled), used to remove empty cells outside the map. The flood fill is done at the specified depth (between 1 and 16) of the OctoMap.");
 
+    RTABMAP_PARAM(Marker, Strategy,               int,   0,     "Marker detection implementation: 0=OpenCV, 1=AprilTag");
     RTABMAP_PARAM(Marker, Dictionary,             int,   0,     "Dictionary to use: DICT_ARUCO_4X4_50=0, DICT_ARUCO_4X4_100=1, DICT_ARUCO_4X4_250=2, DICT_ARUCO_4X4_1000=3, DICT_ARUCO_5X5_50=4, DICT_ARUCO_5X5_100=5, DICT_ARUCO_5X5_250=6, DICT_ARUCO_5X5_1000=7, DICT_ARUCO_6X6_50=8, DICT_ARUCO_6X6_100=9, DICT_ARUCO_6X6_250=10, DICT_ARUCO_6X6_1000=11, DICT_ARUCO_7X7_50=12, DICT_ARUCO_7X7_100=13, DICT_ARUCO_7X7_250=14, DICT_ARUCO_7X7_1000=15, DICT_ARUCO_ORIGINAL = 16, DICT_APRILTAG_16h5=17, DICT_APRILTAG_25h9=18, DICT_APRILTAG_36h10=19, DICT_APRILTAG_36h11=20");
     RTABMAP_PARAM(Marker, Length,                 float, 0,     "The length (m) of the markers' side. 0 means automatic marker length estimation using the depth image (the camera should look at the marker perpendicularly for initialization).");
     RTABMAP_PARAM(Marker, MaxDepthError,          float, 0.01,  uFormat("Maximum depth error between all corners of a marker when estimating the marker length (when %s is 0). The smaller it is, the more perpendicular the camera should be toward the marker to initialize the length.", kMarkerLength().c_str()));

corelib/src/CMakeLists.txt

@@ -533,6 +533,13 @@ IF(FastCV_FOUND)
 	)
 ENDIF(FastCV_FOUND)
 
+IF(apriltag_FOUND)
+	SET(LIBRARIES
+		${LIBRARIES}
+		apriltag::apriltag
+	)
+ENDIF(apriltag_FOUND)
+
 IF(opengv_FOUND)
     SET(LIBRARIES
         ${LIBRARIES}

corelib/src/MarkerDetector.cpp

@@ -29,16 +29,27 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <rtabmap/core/util2d.h>
 #include <rtabmap/utilite/ULogger.h>
 
+#ifdef RTABMAP_APRILTAG
+extern "C" {
+#include "apriltag/apriltag.h"
+#include "apriltag/apriltag_pose.h"
+#include "apriltag/tag36h11.h"
+}
+#endif
+
 namespace rtabmap {
 
-MarkerDetector::MarkerDetector(const ParametersMap & parameters)
+MarkerDetector::MarkerDetector(const ParametersMap & parameters) :
+	strategy_((Strategy)Parameters::defaultMarkerStrategy()),
+	markerLength_(Parameters::defaultMarkerLength()),
+	maxDepthError_(Parameters::defaultMarkerMaxDepthError()),
+	maxRange_(Parameters::defaultMarkerMaxRange()),
+	minRange_(Parameters::defaultMarkerMinRange()),
+	dictionaryId_(Parameters::defaultMarkerDictionary()),
+	apriltagLibDetector_(NULL),
+	apriltagLibFamily_(NULL)
 {
 #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)
@@ -53,16 +64,35 @@ MarkerDetector::MarkerDetector(const ParametersMap & parameters)
 #else
 	detectorParams_->doCornerRefinement = Parameters::defaultMarkerCornerRefinementMethod()!=0;
 #endif
-	parseParameters(parameters);
 #endif
+
+	parseParameters(parameters);
 }
 
 MarkerDetector::~MarkerDetector() {
-
+#ifdef RTABMAP_APRILTAG
+	if(apriltagLibDetector_)
+	{
+		apriltag_detector_destroy(((apriltag_detector_t*)apriltagLibDetector_));
+	}
+	if(apriltagLibFamily_)
+	{
+		tag36h11_destroy((apriltag_family_t*)apriltagLibFamily_);
+	}
+#endif
 }
 
 void MarkerDetector::parseParameters(const ParametersMap & parameters)
 {
+	int strategy = strategy_;
+	Parameters::parse(parameters, Parameters::kMarkerStrategy(), strategy);
+	strategy_ = (Strategy)strategy;
+	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_);
+
 #ifdef HAVE_OPENCV_ARUCO
 	detectorParams_->adaptiveThreshWinSizeMin = 3;
 	detectorParams_->adaptiveThreshWinSizeMax = 23;
@@ -95,13 +125,9 @@ void MarkerDetector::parseParameters(const ParametersMap & parameters)
 	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)
+	if(dictionaryId_ >= 17 && strategy_ == 0)
 	{
 		UERROR("Cannot set AprilTag dictionary. OpenCV version should be at least 3.4.2, "
 				"current version is %s. Setting %s to default (%d)",
@@ -121,6 +147,28 @@ void MarkerDetector::parseParameters(const ParametersMap & parameters)
 	*dictionary_ = cv::aruco::getPredefinedDictionary(cv::aruco::PREDEFINED_DICTIONARY_NAME(dictionaryId_));
 #endif
 #endif
+
+#ifdef RTABMAP_APRILTAG
+	if(apriltagLibDetector_)
+	{
+		apriltag_detector_destroy(((apriltag_detector_t*)apriltagLibDetector_));
+		apriltagLibDetector_ = NULL;
+	}
+	if(apriltagLibFamily_)
+	{
+		tag36h11_destroy((apriltag_family_t*)apriltagLibFamily_);
+		apriltagLibFamily_ = NULL;
+	}
+	apriltagLibDetector_ = apriltag_detector_create();
+	((apriltag_detector_t*)apriltagLibDetector_)->nthreads = 2;
+	((apriltag_detector_t*)apriltagLibDetector_)->quad_decimate = 1;
+	apriltagLibFamily_  = tag36h11_create();
+	apriltag_detector_add_family(((apriltag_detector_t*)apriltagLibDetector_), (apriltag_family_t*)apriltagLibFamily_);
+
+	if (errno == ENOMEM) {
+		UFATAL("Unable to add family to detector due to insufficient memory to allocate the tag-family decoder with the default maximum hamming value of 2. Try choosing an alternative tag family.");
+	}
+#endif
 }
 
 std::map<int, Transform> MarkerDetector::detect(const cv::Mat & image, const CameraModel & model, const cv::Mat & depth, float * markerLengthOut, cv::Mat * imageWithDetections)
@@ -207,18 +255,97 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
 
     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;
+	std::vector<Transform> poses;
 
 	// 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);
+	if(strategy_ == kStrategyApriltag)
+	{
+#ifdef RTABMAP_APRILTAG
+		// Make an image_u8_t header for the Mat data
+		UASSERT(image.type() == CV_8UC1);
+		image_u8_t im = {image.cols, image.rows, (int)image.step, image.data};
+
+		zarray_t *apriltagDetections = apriltag_detector_detect(((apriltag_detector_t*)apriltagLibDetector_), &im);
+
+		if (errno == EAGAIN) {
+			UFATAL("Unable to create the %d threads requested.", ((apriltag_detector_t*)apriltagLibDetector_)->nthreads);
+			exit(-1);
+		}
+
+		for (int i = 0; i < zarray_size(apriltagDetections); i++) {
+            apriltag_detection_t *det;
+            zarray_get(apriltagDetections, i, &det);
+
+			apriltag_detection_info_t info;
+			info.det = det;
+			info.tagsize = markerLength_<=0.0?1.0f:markerLength_;
+			info.fx = model.fx();
+			info.fy = model.fy();
+			info.cx = model.cx();
+			info.cy = model.cy();
+
+			// Then call estimate_tag_pose.
+			apriltag_pose_t pose;
+			double err = estimate_tag_pose(&info, &pose);
+			if (pose.R && pose.t)
+			{
+				Transform t(MATD_EL(pose.R, 0, 0), MATD_EL(pose.R, 0, 1), MATD_EL(pose.R, 0, 2), MATD_EL(pose.t, 0, 0),
+							MATD_EL(pose.R, 1, 0), MATD_EL(pose.R, 1, 1), MATD_EL(pose.R, 1, 2), MATD_EL(pose.t, 1, 0),
+							MATD_EL(pose.R, 2, 0), MATD_EL(pose.R, 2, 1), MATD_EL(pose.R, 2, 2), MATD_EL(pose.t, 2, 0));
+				poses.push_back(t);
+
+				corners.push_back(std::vector<cv::Point2f>(4));
+				for(int i=0; i<4; ++i)
+				{
+					corners.back()[i].x = det->p[i][0];
+					corners.back()[i].y = det->p[i][1];
+					UDEBUG("Marker %d corner %d : %f %f", det->id, i, corners.back()[i].x, corners.back()[i].y);
+				}
+				ids.push_back(det->id);
+				UDEBUG("Add marker %d (err = %f)", det->id, err);
+			}
+			else
+			{
+				UWARN("Failed to compute pose for marker %d, ignoring...", det->id);
+			}
+
+			// Free pose memory
+			if (pose.R) matd_destroy(pose.R);
+			if (pose.t) matd_destroy(pose.t);
+        }
+
+		apriltag_detections_destroy(apriltagDetections);
 #else
-	cv::aruco::detectMarkers(image, *dictionary_, corners, ids, *detectorParams_, rejected);
+		UERROR("RTAB-Map is not built with apriltag library.");
 #endif
+	}
+	else // opencv
+	{
+		std::vector< cv::Vec3d > rvecs, tvecs;
+#ifdef HAVE_OPENCV_ARUCO
+#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
+		cv::aruco::estimatePoseSingleMarkers(corners, markerLength_<=0.0?1.0f:markerLength_, model.K(), model.D(), rvecs, tvecs);
+
+		for(size_t i=0; i<ids.size(); ++i)
+		{
+			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]);
+			poses.push_back(t);
+		}
+#else
+	UERROR("RTAB-Map is not built with \"aruco\" module from OpenCV.");
+#endif
+	}
+
 	UDEBUG("Markers detected=%d rejected=%d", (int)ids.size(), (int)rejected.size());
 	if(ids.size() > 0)
 	{
@@ -238,7 +365,6 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
             }
         }
 
-		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)
 		{
@@ -256,7 +382,7 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
 				// best depth estimation)
 				if(d>0 && d1>0 && d2>0 && d3>0 && d4>0)
 				{
-                    float scale = d/tvecs[i].val[2];
+                    float scale = d / poses[i].z();
                     
 					if( fabs(d-d1) < maxDepthError_ &&
                         fabs(d-d2) < maxDepthError_ &&
@@ -265,8 +391,10 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
 					{
                         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());
+						poses[i].x() *= length;
+						poses[i].y() *= length;
+						poses[i].z() *= length;
+						UWARN("Automatic marker length estimation: id=%d depth=%fm length=%fm", ids[i], d, length);
 					}
 					else
 					{
@@ -297,7 +425,9 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
                 if(findIter!=markerLengths.end())
                 {
                     length = findIter->second;
-                    tvecs[i] *= length;
+                    poses[i].x() *= length;
+					poses[i].y() *= length;
+					poses[i].z() *= length;
                 }
                 else
                 {
@@ -316,17 +446,13 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
 
 			// 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_))
+			if((maxRange_ <= 0 || poses[i].z() < maxRange_) &&
+				(minRange_ <= 0 || poses[i].z() > 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;
+				Transform pose = model.localTransform() * poses[i];
 				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());
+				UDEBUG("Marker %d detected in base_link: %s, optical_link=%s, local transform=%s",
+					ids[i], pose.prettyPrint().c_str(), poses[i].prettyPrint().c_str(), model.localTransform().prettyPrint().c_str());
 			}
 		}
 		if(markerLength_ == 0 && !scales.empty())
@@ -363,6 +489,7 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
 
 	if(imageWithDetections)
 	{
+#ifdef HAVE_OPENCV_ARUCO
 		if(image.channels()==1)
 		{
 			cv::cvtColor(image, *imageWithDetections, cv::COLOR_GRAY2BGR);
@@ -380,19 +507,21 @@ std::map<int, MarkerInfo> MarkerDetector::detect(const cv::Mat & image,
                 std::map<int, MarkerInfo>::iterator iter = detections.find(ids[i]);
                 if(iter!=detections.end())
                 {
+					cv::Vec3d rvec;
+					cv::Vec3d tvec(poses[i].x(), poses[i].y(), poses[i].z());
+					cv::Rodrigues(poses[i].rotationMatrix(), rvec);								
 #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);
+                    cv::drawFrameAxes(*imageWithDetections, model.K(), model.D(), rvec, tvec, iter->second.length() * 0.5f);
 #else
-                    cv::aruco::drawAxis(*imageWithDetections, model.K(), model.D(), rvecs[i], tvecs[i], iter->second.length() * 0.5f);
+                    cv::aruco::drawAxis(*imageWithDetections, model.K(), model.D(), rvec, tvec, iter->second.length() * 0.5f);
 #endif
                 }
 			}
 		}
-	}
-
 #else
-	UERROR("RTAB-Map is not built with \"aruco\" module from OpenCV.");
+		UERROR("RTAB-Map is not built with \"aruco\" module from OpenCV. Cannot draw markers on image.");
 #endif
+	}
 
 	return detections;
 }