Slide 1

Augmented Reality and 3D modellingDone by Stafford JoematSupervised by Mr James Connan and Mr Mehrdad GhaziasgarPROJECT OVERVIEW Marker-based Augmented Reality uses a camera and a visual marker, to determine the center of orientation and range of its coordinate system. The system is effectively a driver that allows users to superimpose a 3D object on a predefined marker, across multiple frames using fixed input video source.

Requirements Analysis

Object Oriented Analysis

Implementation

Testing Issues

User Manual

ITRODUCTION For this presentation I will be talking about.3REQUIREMENTS ANALYSISEquipment and Software neededHigh performance computer2 mega pixel webcamAR marker with many good featuresWindows XP or better

OpenCV libraryOpenGL Glut library

High performance computer is needed as marker detection is a process intensive process.

A 2 mega pixel webcam is needed to provide a good resolution for clear images.

AR marker with many good features is necessary for a stable marker location

OpenCV and OpenGl libraries to perform computations

4

OBJECT ORIENTATED ANALYSISOpenCV retrieves images from the webcam and performs grey scaling,

Surf then detects the markers location on the input video stream, received from opencv

OpenGl then draws the 3D object and performs and perspective operations based on the markers location.5IMPLEMENTATION

Extract frames

Grayscale

Feature detection

Feature comparison

Stabilized using a running average with selectivity.The frames are extracted from the input video stream.

Grey scaling is done to speed up the performance of the system

Feature detection is then applied on the predetermined marker

Feature detection and Comparison = SURF

6IMPLEMENTATIONPerspective comparison

Draw 3D object and perform Perspective transformation

Superimpose 3D object on extracted frames

Display frames

Perspective Comparison is done on marker, which allows perspective transformation to be performed on the 3d object.

The 3d object is then drawn, transformed and superimposed on extracted frames

The frames are then displayed

7TESTING THE SYSTEM

Test different depth

Test system with different markers

Test system with different objects TESTING THE SYSTEM

Different depth test using Open GL

Background image3D object usedVirtual Camera Opengl uses Perspective Projection which means the farther the 3d object is from the virtual camera, the smaller it appears in the final image.

Thus to map x,y window coordinates to Opengl coordinates I calibrated the virtual cameras depth ratio to correspond to a webcams depth from the marker. The length between the marker and the webcam must be 34+-cm for this reason the system is limited on the z-axis.9TESTING THE SYSTEM

Test system with different markers

Right MarkerLeft MarkerLeft marker is not a perfect square and has less features to track.

Right marker is a perfect square and has many features to track.

10TESTING THE SYSTEM

Test system with different objects

11USER MANUAL

Connect webcam

Get printed marker ready

Run executable

Put marker in front of webcam

12http://internet.suite101.com/article.cfm/using_printable_augmented_reality_marker_tagshttp://technotecture.com/augmentedrealityhttp://opencv.willowgarage.com/wiki/http://www.cs.cmu.edu/~cil/vision.htmlhttp://www.adobe.com/devnet/flash/articles/augmented_reality.htmlwww.hotcards.comREFERENCES