MapBuilderWifi.h

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/*
Copyright (c) 2010-2016, Mathieu Labbe - IntRoLab - Universite de Sherbrooke
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
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      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the Universite de Sherbrooke nor the
      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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*/

#ifndef MAPBUILDERWIFI_H_
#define MAPBUILDERWIFI_H_

#include "MapBuilder.h"
#include "rtabmap/core/UserDataEvent.h"

using namespace rtabmap;

// A percentage value that represents the signal quality
// of the network. WLAN_SIGNAL_QUALITY is of type ULONG.
// This member contains a value between 0 and 100. A value
// of 0 implies an actual RSSI signal strength of -100 dbm.
// A value of 100 implies an actual RSSI signal strength of -50 dbm.
// You can calculate the RSSI signal strength value for wlanSignalQuality
// values between 1 and 99 using linear interpolation.
inline int dBm2Quality(int dBm)
{
        // dBm to Quality:
    if(dBm <= -100)
        return 0;
    else if(dBm >= -50)
        return 100;
    else
        return 2 * (dBm + 100);
}

class MapBuilderWifi : public MapBuilder
{
        Q_OBJECT
public:
        // Camera ownership is not transferred!
        MapBuilderWifi(CameraThread * camera = 0) :
                MapBuilder(camera)
        {}

        virtual ~MapBuilderWifi()
        {
                this->unregisterFromEventsManager();
        }

protected:
        virtual void handleEvent(UEvent * event)
        {
                if(event->getClassName().compare("UserDataEvent") == 0)
                {
                        UserDataEvent * rtabmapEvent = (UserDataEvent *)event;
                        // convert userData to wifi levels
                        if(!rtabmapEvent->data().empty())
                        {
                                UASSERT(rtabmapEvent->data().type() == CV_64FC1 &&
                                                rtabmapEvent->data().cols == 2 &&
                                                rtabmapEvent->data().rows == 1);

                                // format [int level, double stamp]
                                int level = rtabmapEvent->data().at<double>(0);
                                double stamp = rtabmapEvent->data().at<double>(1);
                                wifiLevels_.insert(std::make_pair(stamp, level));
                        }
                }
                MapBuilder::handleEvent(event);
        }

protected slots:
        virtual void processStatistics(const rtabmap::Statistics & stats)
        {
                processingStatistics_ = true;

                const std::map<int, Transform> & poses = stats.poses();
                QMap<std::string, Transform> clouds = cloudViewer_->getAddedClouds();

                //============================
                // Add WIFI symbols
                //============================
                std::map<double, int> nodeStamps; // <stamp, id>

                for(std::map<int, Signature>::const_iterator iter=stats.getSignatures().begin();
                        iter!=stats.getSignatures().end();
                        ++iter)
                {
                        // Sort stamps by stamps->id
                        nodeStamps.insert(std::make_pair(iter->second.getStamp(), iter->first));
                }

                int id = 0;
                for(std::map<double, int>::iterator iter=wifiLevels_.begin(); iter!=wifiLevels_.end(); ++iter, ++id)
                {
                        // The Wifi value may be taken between two nodes, interpolate its position.
                        double stampWifi = iter->first;
                        std::map<double, int>::iterator previousNode = nodeStamps.lower_bound(stampWifi); // lower bound of the stamp
                        if(previousNode!=nodeStamps.end() && previousNode->first > stampWifi && previousNode != nodeStamps.begin())
                        {
                                --previousNode;
                        }
                        std::map<double, int>::iterator nextNode = nodeStamps.upper_bound(stampWifi); // upper bound of the stamp

                        if(previousNode != nodeStamps.end() &&
                           nextNode != nodeStamps.end() &&
                           previousNode->second != nextNode->second &&
                           uContains(poses, previousNode->second) && uContains(poses, nextNode->second))
                        {
                                Transform poseA = poses.at(previousNode->second);
                                Transform poseB = poses.at(nextNode->second);
                                double stampA = previousNode->first;
                                double stampB = nextNode->first;
                                UASSERT(stampWifi>=stampA && stampWifi <=stampB);

                                Transform v = poseA.inverse() * poseB;
                                double ratio = (stampWifi-stampA)/(stampB-stampA);

                                v.x()*=ratio;
                                v.y()*=ratio;
                                v.z()*=ratio;

                                Transform wifiPose = (poseA*v).translation(); // rip off the rotation

                                std::string cloudName = uFormat("level%d", id);
                                if(clouds.contains(cloudName))
                                {
                                        if(!cloudViewer_->updateCloudPose(cloudName, wifiPose))
                                        {
                                                UERROR("Updating pose cloud %d failed!", id);
                                        }
                                }
                                else
                                {
                                        // Make a line with points
                                        int quality = dBm2Quality(iter->second)/10;
                                        pcl::PointCloud<pcl::PointXYZRGB>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZRGB>);
                                        for(int i=0; i<10; ++i)
                                        {
                                                // 2 cm between each points
                                                // the number of points depends on the dBm (which varies from -30 (near) to -80 (far))
                                                pcl::PointXYZRGB pt;
                                                pt.z = float(i+1)*0.02f;
                                                if(i<quality)
                                                {
                                                        // yellow
                                                        pt.r = 255;
                                                        pt.g = 255;
                                                }
                                                else
                                                {
                                                        // gray
                                                        pt.r = pt.g = pt.b = 100;
                                                }
                                                cloud->push_back(pt);
                                        }
                                        pcl::PointXYZRGB anchor(255, 0, 0);
                                        cloud->push_back(anchor);
                                        //UWARN("level %d -> %d pose=%s size=%d", level, iter->second.first, wifiPose.prettyPrint().c_str(), (int)cloud->size());
                                        if(!cloudViewer_->addCloud(cloudName, cloud, wifiPose, Qt::yellow))
                                        {
                                                UERROR("Adding cloud %d to viewer failed!", id);
                                        }
                                        else
                                        {
                                                cloudViewer_->setCloudPointSize(cloudName, 5);
                                        }
                                }
                        }
                }

                //============================
                // Add RGB-D clouds
                //============================
                MapBuilder::processStatistics(stats);
        }

private:
        std::map<double, int> wifiLevels_;
};


#endif /* MAPBUILDERWIFI_H_ */