Computer Graphics for Large- Scale Immersive Theaters

Transcription

1 Computer Graphics for Large- Scale Immersive Theaters Spherical Image Generation and Projection Ed Lantz Product Development Manager Spitz, Inc.

2 Immersive Display Image Metrics Field of View Brightness Resolution

3 Field of View Total horizontal and vertical image angle in spherical coordinates with respect to viewer s eyepoint -or- spherical screen origin

4 Image Brightness Video Projector Brightness» Lumens brightest video projector is 12,000 Lumens Theater Brightness» Foot Lamberts SMPTE standard for film is 16 ftl 1 Foot Lambert = 1 Lumen over 1 Sq.. Ft. for Lambertian Screen with 100% Reflectivity

5 Image Resolution Acuity of Eye = 1 arcminute/line pair 1 arcminute = 1/60 degrees = 0.017º Ideally it takes 2 pixels to represent a resolvable line pair # of Resolvable line pairs < # pixels/2

6 Why a Sphere? Greater Immersivity than Flat Screen Flat screen theoretically limited to 180º Sphere easily provides 360º horizontal FOV Graceful Degradation of Off-Axis Perspective Rectilinear displays introduce artifacts i.e. CAVE

7 Cubic Distortion Ideal Viewpoint Offset Viewpoint

8 Spherical Distortion Ideal Viewpoint Offset Viewpoint

9 Theater Design Dome Tilt Level dome requires reclined seating Tilted dome + stadium seating brings dome screen into viewer s field of view

10 Theater Design Seating Configurations Unidirectional seating provides single point of focus Concentric seating popular in old planetarium designs and special applications

11 Theater Design Goal: When the lights go out... The theater disappears! Minimize all reality intrusions

12 Skinning a Sphere Spherical Mastering Format (Immersoid) Single large frame representing entire sphere Master format for archiving, distribution, etc. Independent of particular projection geometry Defined only by resolution and field-of-view Spherical Projection Format (Sub Frames) Multi-pipe format that matches projection geometry Sub frames individually warped and blended

13 Spherical Mastering Format +90º Equidistant Cylindrical Latitude 0º -90º -180º 0º +180º Longitude

14 Equidistant Cylindrical Master Entire Edge Maps to Single Pixel at Pole

15 Equidistant Cylindrical Master

16 Spherical Mastering Format Longitude 0º +90º +90º -90º Polar Fisheye (Equidistant Polar) 0º -90º 180º

17 Polar Fisheye Mastering Entire Outside Edge Maps to Single Pixel at South Pole Polar Image Fills 78.5% of Square Frame

18 Polar Fisheye Mastering

19 Polar versus Cylindrical Mastering N Pixels Pole-to-Pole N Pixels Pole-to-Pole File Size = 4N 2 File Size = 2N 2

20 Skinning a Sphere with Platonic Solids

21 Skinning a Sphere - Cubic Mapping File Size > 1.5N 2 Advantage - Efficient File Format Disadvantage - Images are Discontinuous

22 Spherical Projection Formats Single Projector (Fisheye) Arrayed/Mosaicked Projectors (Edge-Blended)

23 Fisheye Projection Polar Fisheye Source Image Simple Configuration Limited Hemispheric Resolution (1024x1024 pixels) Requires Obtrusive Projector Inside Theater Space

24 Fisheye Projection Applications Elumens VisionStation Series Ideal Dome Production Monitors! Screen Diameters from 1.6m to 5m Resolution of 1365x1024 pixels And Growing Image Courtesy Elumens Corp.

25 Mosaicked Projection Polar Source is Split Into Sub- Frames and Edge- Blended Sub Frame 1 Sub Frame 2 Sub Frame 3 Sub Frame 4

26 Many Projection Geometries Five Projectors Six Projectors Seven Projectors

27 Mosaicking Provides Simultaneous High Resolution, Wide FOV Wide FOV, LoRes Narrow FOV HiRes Wide FOV, HiRes Single Channel Single Channel N Channels Mosaicked

28 Mosaicking Pros and Cons Limitless Resolution over Chosen FOV Greater Brightness for Given Projector Type Master Image Must Be Parsed, Warped, Blended Multiple Projectors to Align, Color Balance Multiple Video Channels or Image Generator Pipes Obviously More Complex and Costly But Cinematic Quality Image over Hemisphere

29 Volkswagen Autostadt: Hemispheric Digital Cinema million pixels using 4x Barco DLP

30 Edge Blending and Spherical Mapping Techniques Pre-Rendered Blends and Mapping Post-production processing of sub-frames No special playback hardware Realtime Blends and Mapping Allows realtime display of CGI, video sources, etc. Dome becomes large virtual desktop!

31 Pre-Rendered Edge Blends and Spherical Mapping 2D image processing with DigiDome or PolyDome Ad-hoc process using 3D renderer On-site tweaking possible prior to processing All immersive content must be post-processed Live spherical images not possible

32 Realtime Edge Blends Requires Edge-Blend Hardware Panoram s Panomaker SEOS s DigiBlend Integral to Barco, Sony, 3D-Perception projectors Control Over Blend Regions Separate Interactive Control of R,G,B Blends Night/Day Gamma Mapping

33 Realtime Spherical Mapping Input Flat Plane, Polar, or Equidistant Source Realtime Digital Warping SEOS s Mercator 3D Perception Projector Geometry Control Requires CRT projectors Geometry adjustments (keystone, bow, etc.) Orthogonal adjustments (bilinear interpolation, etc.)

34 Video Projector Technologies LCoS/D-ILA - Liquid Crystal on Silicon LCD - Transmissive Liquid Crystal Display CRT - Cathode Ray Tube Calligraphic CRT DLP - Digital Light Processor Laser Projection - Various Technologies

35 DLP Projectors MEMS Mirrors on Silicon Substrate High Contrast >1000:1 Good Resolution 1280x1024 Very High Brightness 12,000 Lumens Images Courtesy Texas Instruments

36 LCoS Projectors Liquid Crystal on Silicon Substrate Excellent Pixel Fill Factor - No Screen Door Effect High Contrast - up to 1000:1 High Brightness - up to 7000 Lumens QXGA Resolution x1536 pixels Image Courtesy JVC Corp.

37 CRT Projectors Analog Technology - Continuous Image (no pixels) Highest Resolution x2000 Addressable Pixels Analog Image is Subject to Drift Very Low Brightness - 270/1200 Lumens for 9 CRT Ultra High Frame Sequential Contrast :1 The ONLY Projector that Fades to True Black! Image Courtesy Christie, Inc.

38 Calligraphic CRT Projectors Light Points and Lines Only Points are 1/3 the Diameter of Raster Pixels Combination of Raster/Calligraphic Available Digistar is Full Dome Calligraphic Star Projector Digistar Images Courtesy Evans & Sutherland, Inc.

39 Laser Projectors Promises High Resolution, Very High Contrast New Semiconductor-Based Solid-State Lasers Several Competing Systems Emerging SGI/ZEISS/Schneider Projector Optimized for Dome Projection Images Courtesy Silicon Graphics, Inc.

40 Image Generation: Feeding the Dome Pre-Rendered Video/Graphics Digital Graphics Playback Resolutions up to 1600x1200, Video Resolutions up to 1920x1080i Pre-rendering provides superior image quality Realtime Graphics Provides user interactivity Rendering speeds rapidly increasing Live Video Feeds Immersive Cameras Videoconferencing Interactive performance

41 Playback of Pre-Rendered Graphics Standard Video Formats CCIR-601 Format (720x486) Requires expensive video line interpolators HD 1920x1080i 16:9 format not well suited to dome geometry Graphics Formats 1280x1024 provides good resolution 1600x1200 provides excellent resolution Multichannel Graphics/Video Servers RAID technologies Storage capacity in multi TB Graphics compression available

42 Realtime Image Generation Dome Systems Pioneered in Training Simulators Immersive Visualization & VR Workspaces CAVE, Reality Center, etc. - group interactivity Image Courtesy Spitz, Inc.

43 Realtime Image Generation Networked PC s: (MetaVR VRSG, SGI Graphics Cluster ) Image Courtesy MetaVR

44 Realtime Image Generation GeForce3-based graphics cards (NVIDIA): 1 Billion Bilinear Filtered, Multi-Textured Pixels/second 64Mb of DDR Memory GPU capable of 800 Billion Operations per Second Transform, Clip and Light 31 M Triangles per Second Full Scene Anti-Aliasing up to 1280x1024 Maximum Texture Map Size 2048x2048-pixels

45 Realtime Image Generation Mainframe Solutions Still Offer Highest Performance Image Courtesy Silicon Graphics, Inc.

46 Live Action on the Sphere... Immersive Media s Dodecahedral Camera Image Courtesy Immersive Media Company For more links:

47 Telepresence CMU s Nomad Robot Tested by NASA Ames in Atacama Desert Live Audience Telepresence

48 Immersing the World Special Thanks to: Elumens Corp. Evans & Sutherland MetaVR Silicon Graphics Corp. Spitz, Inc.