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Graphics System 2012, Fall. Overview of Graphics System Graphics Hardware  Video Display Devices CRT Basic Type of CRT –Random-Scan Displays –Raster-Scan-Displays.

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Presentation on theme: "Graphics System 2012, Fall. Overview of Graphics System Graphics Hardware  Video Display Devices CRT Basic Type of CRT –Random-Scan Displays –Raster-Scan-Displays."— Presentation transcript:

1 Graphics System 2012, Fall

2 Overview of Graphics System Graphics Hardware  Video Display Devices CRT Basic Type of CRT –Random-Scan Displays –Raster-Scan-Displays Flat-Panel Displays  Others Graphics Software

3 Video Display Devices Cathode-Ray Tube(CRT) (cathode ray)

4 CRT Basic (1/2)  Phosphor( 형광체 ) Emit a small spot of light contacted by the electron beam  refresh CRT To maintain image, refresh electron beam repeatedly refresh rate : frequency at which a picture is redrawn  Persistence how long the phosphor continue to emit light after the election beam is removed. defined as the time to takes 1/10 of its original intensity general purpose graphic monitors : from 10 to 60 ms

5 CRT Basic (2/2)  Resolution the maximum number of points that can be displayed without overlap on a CRT simply the total number of points in horizontally and vertically  Aspect Ratio. ratio of vertical points to horizontal points necessary to produce equal-length line in both direction ex) 4/3 : length of 4 points on horizontal line = length of 3points on vertical line Spot Intensity (Gaussian distribution) Overlap position (distinguishable  60%)

6 Type of Display Device Type of CRT  Random-Scan Displays  Raster-Scan-Displays Flat-Panel Displays  Emissive displays  Nonemissive displays

7 Random-Scan Display  Vector Display (calligraphic display)  stored as a set of line-drawing commands in an area of memory (refresh display file, display list, display program)  draw a picture one line at a time

8 Raster-Scan Displays (1/3)  Point plotting device : pixel or pel (Picture Element)  picture info. for all the screen points is stored in separate Memory called Frame buffer (Refresh Buffer)  one row at a time (scan line) from top to bottom

9 Raster-Scan Displays (2/3) Frame buffer  Depth of the buffer area, Number of bit planes  Bitmap: one bit per pixel  Pixmap: multiple bits per pixel Refresh rate  Above about 24 frame per second  Unit of refresh rates  Hz Ex) 60 frames per second (60Hz)

10 Raster-Scan Displays (3/3) Retrace  Horizontal retrace/Vertical retrace Interlaced refresh procedure  used with slower refreshing rates avoid flicker provide adjacent scan lines

11 Vector vs Raster Displays Rendering performance  VD: Sensitive to scene and object complexity  RD: Insensitive to scene and object complexity Memory and processing requirement  VD: variable (depends on scene and object complexity)  RD: Large but constant Screen space aliasing  VG: None  RG: Frequent Rendering of interior  VG: No (boundary only)  RG: Yes (Colored, Shaded and Textured surface)

12 Raster Displays (Bitmap) Intensity for each pixel depends on the size of frame buffer  ex) Black & White system one bit per pixel is needed the frame buffer is commonly called Bitmap

13 Raster Displays (Pixmap)  With multiple bits per pixel, we can display gray-scale or color pictures the frame buffer is commonly called pixmap Ex) Size of Frame Buffer when N=3, with 512 X 512 Size of Frame buffer = 3 X 512 X 512 = 3 X 256k = 768k

14 Color CRT Display Random-scan monitor  Beam-penetration Two layers of phosphor(red, green) Raster-scan monitor  Shadow Mask method Shadow Mask  System has 3 electron guns (R, G, B)  Each Gun is controlled by Frame buffer

15 True Color System

16 Raster Graphics System Architecture

17 Flat-Panel Displays (1/2) Flat-Panel Displays  Video devices that have reduced volume, weight, and power requirement compared to a CRT  emissive displays convert electrical energy into light –Plasma Display Panels (PDP)Plasma Display Panels »Less efficient than CRTs (Not as bright, More power) »Large Pixels(~1mm compared to 0.2mm for CRT) –Field Emission Devices (FED)Field Emission Devices »Limited in size –Light-Emitting Diode (LED)Light-Emitting Diode »LED-backlight LCD televisionLED-backlight LCD television »http://www.rambus.com/kr/technolo gy/applications/display/index.htmlhttp://www.rambus.com/kr/technolo gy/applications/display/index.html Plasma Display Panels Field Emission Display

18 Flat-Panel Displays (2/2)  nonemissive displays convert other source (heat, electromagnetic force,..) into light Liquid-Crystal Displays (LCD)Liquid-Crystal Displays –Liquid Crystal –The LCD's transition between crystalline and liquid states –less energy on average than their plasma counterparts –a limited viewing angle relative to CRT and plasma displaysviewing angle

19 LED vs. PDP vs. LCD (1/2) LED LCD vs. plasma vs. LCD  Light output (brightness) Winner: LED LCD, Loser: Plasma, Runner-Up: CCFL LCD  Black level Winner: Plasma, Loser: CCFL LCD, Runner-up: LED LCD  Contrast ratio : the ratio between the darkest part of the image and the brightest Winner: Plasma, Loser: CCFL LCD, Runner-up: LED LCD  Viewing angle Winner: Plasma, Loser: CCFL LCD/LED LCD

20 LED vs. PDP vs. LCD (2/2)  Energy consumption Winner: LED LCD, Loser: Plasma, Runner-up: CCFL LCD  Price Winner: CCFL LCD, Loser: LED LCD, Runner-up: Plasma  Lifespan Tie  Burn-in : 고정된 화면을 장시간 켜놓거나 동일한 이미지가 반복될 경우 해당 이미지가 사라지지 않고 화면상에 남아 있 는 현상 Tie  Uniformity : a consistent brightness to the image Winner: Plasma, Loser: CCFL LCD/LED LCD

21 Viewing Systems Large-screen stereoscopic view Wide screen view Multi-panel display Curved viewing screen

22 3D Display  360° Light Field Display 360° Light Field Display  Philips 3DTV Philips 3DTV  Hologram TV Hologram TV

23 Input Device  Keyboard, Mouse  Button Boxes, Dials

24 Input Device  Trackballs A ball device that can be rotated with fingers  Spaceballs Provide six degrees of freedom  Joysticks  Data grove

25 Input Device  Digitizer Device for drawing, painting, or interactively selecting position Graphics tablet 3D digitizer Desktop tablet Artistic Digitizer System3D digitizing system

26 Input Device  Image Scanners Hand-held scanner flatbed scanner Wide-format scanner

27 Input Device Plasma panels with touch screens Resistive touch screen overlays Light penVoice system

28 Hard-Copy Devices Picture generated on a dot-matrix printer Desktop pen plotter Roll-free pen plotter

29 Graphics Software (1/2) Two general classifications  general programming package provides a library of graphics functions that can be used in a programming language such as C, C++, Java, or Fortran CG API –Computer-graphics application programming interface Ex) GL, OpenGL, VRML, Java2D, Java3D, Direct3D  Special purpose package design for nonprogrammers who want to generate picture, graphs ex) 3D MAXstudio, Autocad, MAYA, WAVEFRONT, ALIAS, SOFTIMAGE for Workstations

30 Graphics Software (2/2)  Software standard GKS (Graphical Kernel System) 1984  2-D oriented package PHIGS (Programmer’s Hierarchical Interactive Graphics Standard)  extension of GKS  Increased Capabilities for modeling, rendering OpenGL –GL (Graphics Library)  Hardware Independent –OpenGL Architecture Review Board  Script Language Render Man, Radiance, PovRay


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