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Institute for Visualization and Perception ResearchI VPR 1
© Copyright 2000-2010 Haim Levkowitz
Graphics Systems Overview
• Video display devices …
• Input devices …
• Hard-copy devices
• Graphics software ...
Institute for Visualization and Perception ResearchI VPR 2
© Copyright 2000-2010 Haim Levkowitz
Video display devices …
• CRTs …
• Raster-scan displays …
• Vector displays …
• Graphics displays, monitors, workstations ...
Institute for Visualization and Perception ResearchI VPR 3
© Copyright 2000-2010 Haim Levkowitz
CRTs …
• Magnetic deflection
• Accelerating anode
• Electrostatic deflection
• Phosphor persistence
• Intensity distribution
• Resolution
• Aspect ratio
Institute for Visualization and Perception ResearchI VPR 4
© Copyright 2000-2010 Haim Levkowitz
Magnetic deflection
Institute for Visualization and Perception ResearchI VPR 5
© Copyright 2000-2010 Haim Levkowitz
Accelerating anode
Institute for Visualization and Perception ResearchI VPR 6
© Copyright 2000-2010 Haim Levkowitz
Electrostatic deflection
Institute for Visualization and Perception ResearchI VPR 7
© Copyright 2000-2010 Haim Levkowitz
Phosphor persistence
Off OffOn
Brightness
Time
Visibility Threshold
Institute for Visualization and Perception ResearchI VPR 8
© Copyright 2000-2010 Haim Levkowitz
Intensity distribution
Illuminated phosphor spot
Institute for Visualization and Perception ResearchI VPR 9
© Copyright 2000-2010 Haim Levkowitz
Resolution
• Distinguishable
• Spearation > D s.t. I = 0.6 Max I
Institute for Visualization and Perception ResearchI VPR 10
© Copyright 2000-2010 Haim Levkowitz
Aspect ratio
W
HW/H
Institute for Visualization and Perception ResearchI VPR 11
© Copyright 2000-2010 Haim Levkowitz
Raster-scan displays ...
• Pixel
• Scan line
• Frame buffer
• Bitmap/pixmap
• Scan & retrace …
• Frame timing …
Institute for Visualization and Perception ResearchI VPR 12
© Copyright 2000-2010 Haim Levkowitz
Scan & retrace
• Horizontal
• Vertical
• Interlace vs. non interlace …
Institute for Visualization and Perception ResearchI VPR 13
© Copyright 2000-2010 Haim Levkowitz
Interlace vs. non interlace
• 2:1 vs. random
Institute for Visualization and Perception ResearchI VPR 14
© Copyright 2000-2010 Haim Levkowitz
Frame timing …• Retrace: V: 1.3 mSec; H: 10 micro Sec.
• Sync pulse every: V: 1/60 Sec.; H: 63.5 micro Sec.
• 525 scan lines (RS 170 video standard)
• 1st 21: V blanked ==> 483 displayed
• 53 microSec./scan line
• 512 pixels ==> 100 nSec./pixel
• 512 x 1024 ==> 50 nSec./pixel
• 1024 x 1024 ==> 25 nSec./pixel
Institute for Visualization and Perception ResearchI VPR 15
© Copyright 2000-2010 Haim Levkowitz
Frame buffer …
• Simple: Frame buffer is part of system memory ...
• Dedicated frame buffer …
• Video controller …
• Display processor …
Institute for Visualization and Perception ResearchI VPR 16
© Copyright 2000-2010 Haim Levkowitz
Simple: Frame buffer is part of system memory
CPU System Memory
Video Controller
System Bus
Monitor
Institute for Visualization and Perception ResearchI VPR 17
© Copyright 2000-2010 Haim Levkowitz
Dedicated frame buffer
CPUSystem Memory
Video Controller
System Bus
I/O Devices
MonitorFrame Buffer
Institute for Visualization and Perception ResearchI VPR 18
© Copyright 2000-2010 Haim Levkowitz
Video controller
Institute for Visualization and Perception ResearchI VPR 19
© Copyright 2000-2010 Haim Levkowitz
Display processor
• Scan conversion
• Characters: outline curves/pixel grids …
Institute for Visualization and Perception ResearchI VPR 20
© Copyright 2000-2010 Haim Levkowitz
Characters: outline curves / pixel grids
Institute for Visualization and Perception ResearchI VPR 21
© Copyright 2000-2010 Haim Levkowitz
Vector displays …
• Random-scan/stroke
• Line drawing
• Display list
• No shaded image
• Higher resolution
• Smooth lines (beam follows line)
Institute for Visualization and Perception ResearchI VPR 22
© Copyright 2000-2010 Haim Levkowitz
Vector display example …
Institute for Visualization and Perception ResearchI VPR 23
© Copyright 2000-2010 Haim Levkowitz
Graphics displays, monitors, workstations …
• Direct view storage tubes …
• Color CRT monitors …
• Flat-panel displays …
• Three-dimensional viewing devices
• Stereoscopic and virtual-reality systems
Institute for Visualization and Perception ResearchI VPR 24
© Copyright 2000-2010 Haim Levkowitz
Direct view storage tubes• Store in CRT• 2 guns
• Primary: Store• Flood: Maintain
• Advantages• No refresh ==> High res’n, no flicker
• Disadvantages• No color/selective erase; slow
Institute for Visualization and Perception ResearchI VPR 25
© Copyright 2000-2010 Haim Levkowitz
Color CRT monitors …
• Shadow mask
• Composite
• RGB
• 24 bits/pixel
• +16 Million colors
• Full-/true-color
Institute for Visualization and Perception ResearchI VPR 26
© Copyright 2000-2010 Haim Levkowitz
Delta-delta
Institute for Visualization and Perception ResearchI VPR 27
© Copyright 2000-2010 Haim Levkowitz
Flat-panel displays
• Emissive …
• Nonemissive ...
Institute for Visualization and Perception ResearchI VPR 28
© Copyright 2000-2010 Haim Levkowitz
Emissive …
• Electricity --> light• Plasma …• Thin-film electroluminescent …• LED• Flat CRTs
• Electron beams accelerated parallel to screen
Institute for Visualization and Perception ResearchI VPR 29
© Copyright 2000-2010 Haim Levkowitz
Plasma …• Gas-discharged
• “Sandwich”• 2 glass plates
• Vertical ribbons• Horizontal ribbons
• Mixture of gasses (neon)• High brightness• Monochrome
Institute for Visualization and Perception ResearchI VPR 30
© Copyright 2000-2010 Haim Levkowitz
Thin-film electroluminescent …
• Similar to plasma
• Phosphor instead of gas
• Phosphor becomes conductor
Institute for Visualization and Perception ResearchI VPR 31
© Copyright 2000-2010 Haim Levkowitz
Nonemissive
• Optical effects
• Sunlight / other source --> graphics pattern
• LCD ...
Institute for Visualization and Perception ResearchI VPR 32
© Copyright 2000-2010 Haim Levkowitz
LCD …
• Nematic (threadlike) liquid-crystal
• Polarized light
• Internal source / surrounding
• Passive-matrix ...
• Active-matrix ...
Institute for Visualization and Perception ResearchI VPR 33
© Copyright 2000-2010 Haim Levkowitz
Passive-matrix …
• Align to block/transmit• H + V rows of conductors• Pixel: intersection of 2
conductors• On: twist polarized light to pass• Off: don’t twist ==> block• Back lighting• Color: triads/dyes
Institute for Visualization and Perception ResearchI VPR 34
© Copyright 2000-2010 Haim Levkowitz
Active-matrix …
• Transistor at each pixel
• Thin film transistor
• Control voltage at pixel location
• Prevent charge from leaking
Institute for Visualization and Perception ResearchI VPR 35
© Copyright 2000-2010 Haim Levkowitz
Three-dimensional viewing devices
• Varifocal mirror
• Other
Institute for Visualization and Perception ResearchI VPR 36
© Copyright 2000-2010 Haim Levkowitz
Stereoscopic and virtual-reality systems• Stereoscopic
• Eye separation
• Natural / mechanical aid
• Head-mounted displays
• Resolution
• “Legally blind”
• Affect on user
Institute for Visualization and Perception ResearchI VPR 37
© Copyright 2000-2010 Haim Levkowitz
Input devices ...• Keyboards• Mouse, Trackball & Spaceball, Joysticks• Data glove• Digitizers• Image scanners• Touch panels• Light pens• Voice systems
Institute for Visualization and Perception ResearchI VPR 38
© Copyright 2000-2010 Haim Levkowitz
Graphics software
• Graphics pipeline …
• Coordinates representations …
• Transformation pipeline …
• Graphics functions
• Standards
Institute for Visualization and Perception ResearchI VPR 39
© Copyright 2000-2010 Haim Levkowitz
Graphics pipeline …
App’n Model
App’n Program
Graphics System
Device Independent
Device Dependent
App Prog: Use Package
Graphics Sys implementor: Alg’s to scan convert primitives to pixels
Institute for Visualization and Perception ResearchI VPR 40
© Copyright 2000-2010 Haim Levkowitz
Coordinate rep’s …
• Modeling / Local / Master (mc)
• World (wc)
• Physical device / screen (dc)
• Normalized device (nc)
Institute for Visualization and Perception ResearchI VPR 41
© Copyright 2000-2010 Haim Levkowitz
Transformation pipeline …
• mc --> wc --> nc --> dc
Institute for Visualization and Perception ResearchI VPR 42
© Copyright 2000-2010 Haim Levkowitz
Graphics functions
• Output primitives …
• Attributes …
• Transformations …
• Segmentation
• Objects, structures
Institute for Visualization and Perception ResearchI VPR 43
© Copyright 2000-2010 Haim Levkowitz
Output primitives …
• Character string
• Geometric entities
• Point
• Line
• Curve
• Filled area (polygon, circle, ...)
• General
Institute for Visualization and Perception ResearchI VPR 44
© Copyright 2000-2010 Haim Levkowitz
Attributes
• Color
• Line style, thickness
• Text style
• Area-filling patterns
Institute for Visualization and Perception ResearchI VPR 45
© Copyright 2000-2010 Haim Levkowitz
Transformations
• Geometric ...
• Modeling ...
• Viewing ...
Institute for Visualization and Perception ResearchI VPR 46
© Copyright 2000-2010 Haim Levkowitz
Geometric
• Translate
• Rotate
• Scale
• Sheer
Institute for Visualization and Perception ResearchI VPR 47
© Copyright 2000-2010 Haim Levkowitz
Modeling
• Construct object / scene
• Object description
• Modeling coo’s
Institute for Visualization and Perception ResearchI VPR 48
© Copyright 2000-2010 Haim Levkowitz
Viewing …
• Project view of picture
• Specify views
• Selected portion of output
Institute for Visualization and Perception ResearchI VPR 49
© Copyright 2000-2010 Haim Levkowitz
Standards
• Portability
• Core
• GKS
• PHIGS, PHIGS+ …
• Language binding …
• Interface: CGI
• Store / transmit: CGM
Institute for Visualization and Perception ResearchI VPR 50
© Copyright 2000-2010 Haim Levkowitz
PHIGS ...
• Programmer’s Hierarchical Interactive Graphics Standard
• Extension of GKS• Modeling• Color• Surface rendering• Picture manipulation
Institute for Visualization and Perception ResearchI VPR 51
© Copyright 2000-2010 Haim Levkowitz
PHIGS+
• 3-D surface shading extension
Institute for Visualization and Perception ResearchI VPR 52
© Copyright 2000-2010 Haim Levkowitz
Language binding …
• Syntax to access standard graphics functions from a particular language