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Revision as of 08:00, 30 January 2013 by hamishwillee (Talk | contribs)

QAugmentedReality - Local based augmented reality component

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This article describes QAugmentedReality, an augmented reality (AR) engine that makes it easy for you to create AR applications like Nokia City Lens in QML.

Note.pngNote: This is an entry in the PureView Imaging Competition 2012Q2

Article Metadata
Code Example
Source file: QAugmentedReality (Nokia Project)
Tested with
SDK: Qt SDK 1.2
Devices(s): Nokia N8, Nokia C7-00
Compatibility
Platform(s): Nokia Belle
Symbian
Platform Security
Capabilities: Location, NetworkServices,UserEnvironment,ReadUserData
Article
Keywords: Augmented Reality, Camera, GPS, Compass
Created: galazzo (13 Jun 2012)
Last edited: hamishwillee (30 Jan 2013)

Contents

Introduction

QAugmentedReality is an Augmented Reality engine that provides all functionalities to create your own local based augmented reality application like Nokia City Lens or social applications for example displaying your friends location or your parked car location direction.

The component built entirely from scratch, inherits all camera features adding GPS, Accelerometer and Compass support.

Developers just need to setup for each item the longitude, latitude, description text, image and the engine will do the hard work to manage rendering, gps, compass. The component's strength is the model support that allows you to easy manage your data to display. To add a pin into your scene you just need to add a QAugmentedRealityCameraItem element to QAugmentedRealityCameraModel. A video of the component in operation is given below: The media player is loading...

Get Started with QAugmentedReality

  • Download the project from here
  • Include QAugmentedReality directory into your project

.pro

include(QAugmentedReality/AugmentedRealityLibrary.pri)

main.cpp

#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
 
#include <QtDeclarative>
#include "qaugmentedrealitycamera.h"
 
Q_DECL_EXPORT int main(int argc, char *argv[])
{
QScopedPointer<QApplication> app(createApplication(argc, argv));
 
QmlApplicationViewer viewer;
 
qmlRegisterType<QAugmentedRealityCamera>("QAugmentedRealityCamera", 1, 0, "QAugmentedRealityCamera");
qmlRegisterType<QAugmentedRealityCameraModel>("QAugmentedRealityCamera", 1, 0, "QAugmentedRealityCameraModel");
qmlRegisterType<QAugmentedRealityCameraItem>("QAugmentedRealityCamera", 1, 0, "QAugmentedRealityCameraItem");
qmlRegisterType<QAugmentedRealityCameraDelegate>("QAugmentedRealityCamera", 1, 0, "QAugmentedRealityCameraDelegate");
 
// Resize the root QML element to view size
viewer.setResizeMode(QDeclarativeView::SizeRootObjectToView);
 
// Performance optimization flags
viewer.setAttribute(Qt::WA_OpaquePaintEvent);
viewer.setAttribute(Qt::WA_NoSystemBackground);
viewer.viewport()->setAttribute(Qt::WA_OpaquePaintEvent);
viewer.viewport()->setAttribute(Qt::WA_NoSystemBackground);
viewer.setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
 
 
viewer.setOrientation(QmlApplicationViewer::ScreenOrientationLockLandscape);
viewer.setMainQmlFile(QLatin1String("qml/QAugmentedRealitySample/main.qml"));
viewer.showExpanded();
 
return app->exec();
}


QML

import QtQuick 1.1
import QAugmentedRealityCamera 1.0
 
Rectangle {
id:home
width: 640
height: 360
color:"white"
 
QAugmentedRealityCameraModel {
id:pinsModel
pins: [
QAugmentedRealityCameraItem {
latitude: 41.891033
longitude:12.492599
message:"Rome"
source: ":/images/colosseo.jpg"
},
QAugmentedRealityCameraItem {
latitude: 45.463502
longitude:9.187946
message:"Milan"
source: ":/images/milan.jpg"
},
QAugmentedRealityCameraItem {
latitude: 48.856358
longitude:2.352047
message:"Paris"
infoBox: "#FFAA23"
source: ":/images/paris.jpg"
},
QAugmentedRealityCameraItem {
latitude: 51.50746
longitude:-0.127831
message:"London"
},
QAugmentedRealityCameraItem {
latitude: 52.518728
longitude:13.404465
message:"Berlin"
source: ":/images/berlin.jpg"
},
QAugmentedRealityCameraItem {
latitude: 40.714997
longitude:-74.006767
message:"New York"
source: ":/images/new-york.jpg"
},
QAugmentedRealityCameraItem {
latitude: 35.689649
longitude:139.691048
message:"Tokyo"
},
QAugmentedRealityCameraItem {
latitude: -37.813717
longitude:144.962955
message:"Melbourne"
infoBox: "blue"
}
]
}
 
QAugmentedRealityCamera {
id:camera
anchors.fill: parent
resolution: Qt.size(2592,1456)
model: pinsModel
}
 
Component.onCompleted:{
camera.start(camera.availableDevices[0])
 
pinsModel.append({
"latitude": 45.428094,
"longitude": 9.313946,
"message": "Peschiera Borromeo",
"source": ":/images/bino.jpg"
})
pinsModel.append({
"latitude": -34.603541,
"longitude": -58.381748,
"message": "Buenos Aires",
"infoBox" : "white"
})
 
}
}

QAugmentedRealityCamera

QAugmentedRealityCamera is the component that provide not only the camera display feature, but includes GPS, Accelerometer, and Compass to display Pins on screen and being able to move them depending on watching direction.

To add a pin you need setup a QAugmentedRealityCameraModel for the component.

QAugmentedRealityCameraModel

QAugmentedRealityCameraModel has a pins property that have to be filled with QAugmentedRealityCameraItem element.

You can add QAugmentedRealityCameraItem statically or dynamically.

Adding a pin statically

QAugmentedRealityCameraModel {
id:pinsModel
pins: [
QAugmentedRealityCameraItem {
latitude: 41.891033
longitude:12.492599
message:"Rome"
source: ":/images/colosseo.jpg"
}]
}

Adding a pin dynamically

This approach is preferred when fetching data from a database.

Component.onCompleted:{
pinsModel.append({
"latitude": 45.428094,
"longitude": 9.313946,
"message": "Peschiera Borromeo",
"source": ":/images/bino.jpg"
})
}

QAugmentedRealityCameraItem

QAugmentedRealityCameraItem has the following properties:

  • latitude - latitude of the item
  • longitude - longitude of the item
  • message - description text displayed inside the pin
  • infoBox - the color of the box drawn on the left of the pin. This is because to give you the possibility to have pins of different color for your own purpose
  • source - As for infoBox this feature allow you to set an image for your pin. Transparent images are allowed. The infoBox background color will be displayed on transparent areas.

Shooting still images

The component inherits from a base camera component so is possible to capture photos as with the default camera component. The result image will include the augmented reality items in the scene.

This feature will be improved as soon as possible to be fitable with all resolutions.

Ar-201206135237.jpg Ar-201206135324.jpg

Be careful of large distances - the world is not flat

For pins located a very long way away you may see odd effects. Consider the example showcased on the video above - at certain watching angles Berlin, Tokyo and Melbourne appear close together.

Earth-flat.png

This happens because the earth has a spherical shape and points in a sphere are located using polar coordinate system.

Earth-round.png

In our example what happens is that the bearing between Milan, Berlin, Tokyo and Melbourne is quite small - these are therefore shown as close together at some watching angle. This should not be a problem if you're working with objects that are within tens of kilometres or less.

Sample application

Note.pngNote: Don't forget to shake the phone for compass calibration or pins will not be displayed correctly

Further improvements

Improvements that will come as soon as possible:

  • filter item based on max distance, for example to display just items far less then 150mt
  • At time of writing the delegate is static. if possible to allow users to create their own delegate
  • Provided a customizable delegate the next step is to provide a customizable model
  • qmldir usage

Despite improvements that will come the component is easy and powerful enough to start creating your local based augmented reality applications and enjoy with them.

If you have any questions about using the component or suggestions for improvement please add them in the project discussion board.

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