8Hybrid Projection one projector infrared visible for the computer for the human
9Infrared & Visible Projection If we could make a projector the can emit IR imagesCould do full screen location discovery without the viewer’s knowledgeSimultaneously project visible light application content.Chose green for infrared because that is how it is rendered in night-vision cameras.
20Light Source: Lamps Xenon Arc Lamp Lots of IR energy, sometimes 100 timesBut this is energy we can’t see so manufactures use IR cutoff filtersReduces heat and wear on the imaging elementEven if the optics were changedUnmodulated light is hard to use (easy interference)Xenon Arc Lamp
21Light Technologies You are probably familiar with these, but LED stands for light emitting diodeAvailable in a wide variety of form factors, and power, andMost importantly color.
22More Efficient and Better Lifespan The benefit of using an LED light sourceLower heatLower powerSmaller – most of a projector is power supply and coolingHandheld projector becoming possible.Products emerging on market this year, 2007
23IR and Visible Light LEDs 1000 LEDs/mm2 This is our LED light source.Notice only two color bands.Since I’m building these by hand,Don’t have manufacturing capability to create quad color LED arrays that are dense enough.But a commercial manufacturer could easily do this.So, for our proof-of-concept prototype we usevisible red light and invisible infrared.IR and Visible Light LEDs1000 LEDs/mm2University of Strathclyde, Institute of Photonics
24LED Array DMD Lens Projection optics Inside the DLP projectorLED arrayCulminating lens which focuses light ontothe DLP chipDLP reflect light into the barrel of projection optics.Projection optics
25Our Dev Kit: 180 binary images/s High-Speed Dev Kit: 16,500 binary images/sProduction Unit: +50,000 binary images/sWe use a DLP Discovery development kit to control the mirror state on the chip.1024x768 area = 20 binary images60Hz tracking = 2.4% duty cycle of production DMDRequired changes to commercial designs would be minimal.
26Demo of CapabilityUses a second projector for visible content
27Inherent Multi-Stylus Tracking Inherent stylus support on any surfaceMulti simultaneous users with user IDPossible with a minor design change to upcoming generation of DLP projectors.
28Non-Planar and Discontinuous Surfaces Inherent stylus support on any surfaceMulti simultaneous users with user IDPossible with a minor design change to upcoming generation of DLP projectors.
30Concept ApplicationsSimulated using external tracking (calibration)
31Hand-held projection with photosensitive tags In siggraph 2004, explored interaction of handheld projectionSimulated using camera-based tracking, but enabled by IR projector-based trackingSelectionGroupingAnnotating[Siggraph 2004]
32Foldable Interactive Displays [submitted to CHI]
33Acknowledgements Johnny Chung Lee Funded in part by the National Science Foundation under grants IIS and IISFunded in part by Mitsubishi Electric Research LabsJohnny Chung Lee
34Other ways to make invisible patterns Other non-visible wavelengthsSteganographyColor shiftingNoise encodingBit TimingSynchronization may be difficult
35Camera-Based Tracking Requires calibrationRequires markers for segmentationIR sensors + transmitter is less power than 4 IR LEDsDoes not provide IDLimitation on the number of pointsLimitation on tracking rateLimitation on scene/target complexityResolution is not as scalableLess optically robustOptical path geometry and variable illumination
36Projector vs Camera Tracking Sensors provide point IDIndependent of scene/surface complexity
37Space-Labeling Projectors 11 Infrared LED slide projectorsPotentially Low-costPer axis: 500Hz tracking at 10-bitsstacked of 11 LED slide projectorsRequires cylindrical opticsCan do tracking outdoors in complex environmentsAnd in dynamic lightingTracking could be boosted to 25KHz.Outdoor motion tracking