instantreality 1.0

6 Dof Tracking with the Wii-Remote

Keywords:
vision, 6 Dof, wiimote, Wii-Remote, augmented reality
Author(s): Rudolf Adler
Date: 2009-04-15

Summary: This tutorial shows you, how to use the basic features of the 6 Degrees of Freedom Tracker with the Wiimote.

Introduction

The Wiimote needs to be 'paired' (Bluetooth connected) with the PC before you can use it. Pressing 1 and 2 simultaneously puts it into 'discoverable' mode for a few seconds (LEDs will flash - the number of LEDs reflects the battery level).
Image: bluetoothstack.jpg
Image: bluetoothstack_search.jpg
Now you have to connect with your Wiimote, it will be detected as 'Nintendo RVL-CNT-01' (The LED´s on your Wiimote should flash and the status should be "connected") .

IOSensor

The 6dof tracker is loaded like any other Instant IO device via an IOSensor. These are instantvision's fields:

  • InstantCamera_Projection (SFMatrix4f): Camera' projection matrix
  • InstantCamera_Position (SFVec3f): Camera's position
  • InstantCamera_Orientation (SFRotation): Camera's orientation

Code: IOSensor

        <IOSensor DEF='VisionLib' type='VisionLib' configFile='Wiitest_3PointPose.pm'>
    	    <field accessType='outputOnly' name='InstantCamera_Projection'  type='SFMatrix4f'/>
            <field accessType='outputOnly' name='InstantCamera_Position'    type='SFVec3f'/>
    	    <field accessType='outputOnly' name='InstantCamera_Orientation' type='SFRotation'/>

Setting the virtual object's position and orientation relative to the camera

We add a virtual object (a teapot) to the scene.

Code: Add a yellow teapot

    	<Transform DEF='ControlerPosition'>
            <Shape DEF='geo2'>
                <Appearance>
                    <Material DEF='mat' emissiveColor='1 0.5 0' />
                </Appearance>
                <Teapot size='5 5 5' />
            </Shape>
        </Transform>

IR-LED Pattern

You need a Infrared Pattern with 4 Infrared Lights that looks similar to this
Image: IR-LEDPattern.jpg
You have to write the distances between the IR-LED in your .pm file. Bottom left is your first value, bottom right the second, top right your third and top left is your last value and your ID-Point.

Code: Transforming the virtual object relative to the marker

    <LEDModel key="myLEDModel">
      <LED>
      <Position x="0" y="0" z="0"/>
      </LED>
      <LED>
        <Position x="12.2" y="0" z="0"/>
      </LED>
      <LED>
        <Position x="12.2" y="15.4" z="0"/>
      </LED>
      <LED>
        <Position x="0" y="15.4" z="0"/>
      </LED>      
    </LEDModel>
Now we can start Instant Vision. The Led´s on your Wiimote should stop to flash and only one blue light should glow. If we look with the cam in the Wiimote to all 4 Infrared Lights we can interact with the teapot.
Image: teapot.jpg

Tracking with more Pattern

To use more than one Pattern you have to write the ID-Points of all Pattern in your .pm file.

Code: Transforming the virtual object relative to the marker

    <HomgPoint3Container key="IDPoint">
      <HomgPoint3d w="1" x="0" y="15.4" z="0"/>
      <HomgPoint3d w="1" x="2" y="15.4" z="0"/>
      <HomgPoint3d w="1" x="4" y="15.4" z="0"/>
    </HomgPoint3Container>
     
    <LEDModel key="myLEDModel">
      <LED>
      <Position x="0" y="0" z="0"/>
      </LED>
      <LED>
        <Position x="12.2" y="0" z="0"/>
      </LED>
      <LED>
        <Position x="12.2" y="15.4" z="0"/>
      </LED>
      <LED>
        <Position x="0" y="15.4" z="0"/>
      </LED>      
    </LEDModel>

Use the Buttons of the Wiimote

To use the Buttons of the Wiimote you have to enable dataAttributeSlots and add your DataBase.

Code: IOSensor

        <IOSensor DEF='VisionLib' type='VisionLib' configFile='Tutorial6dofTracking.pm' dataAttributeSlots='true' addDataBases='WiiData1;InstantCamera;'>
    	    <field accessType='outputOnly' name='InstantCamera_ModelView'     type='SFMatrix4f'/>
    	    <field accessType='outputOnly' name='InstantCamera_Projection'    type='SFMatrix4f'/>
            <field accessType='outputOnly' name='InstantCamera_Position'      type='SFVec3f'/>
    	    <field accessType='outputOnly' name='InstantCamera_Orientation'   type='SFRotation'/>
            
            <field accessType='outputOnly' name='WiiData1_out_ButtonAPressed' type='SFString'/>
        </IOSensor>

Now you can interact with the A Button of your Wiimote.

To put something in the Wiimote (Rumble or LED´s)

Code: IOSensor

            <IOSensor DEF='VisionLib' type='VisionLib' configFile='Tutorial6dofTracking.pm' dataAttributeSlots='true' addDataBases='WiiData1;InstantCamera;'>
    	    <field accessType='outputOnly' name='InstantCamera_ModelView'   type='SFMatrix4f'/>
    	    <field accessType='outputOnly' name='InstantCamera_Projection'  type='SFMatrix4f'/>
            <field accessType='outputOnly' name='InstantCamera_Position'    type='SFVec3f'/>
    	    <field accessType='outputOnly' name='InstantCamera_Orientation' type='SFRotation'/>
            
            <!--Wiidata Input Slots-->
            <field accessType='inputOnly' name='WiiData1_in_Rumble' type='SFString'/>
        </IOSensor>
Files: