Input/Output Devices Graphical Interface Systems Dr. M. Al-Mulhem Feb. 1, 2008.
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Transcript of Input/Output Devices Graphical Interface Systems Dr. M. Al-Mulhem Feb. 1, 2008.
Input/Output DevicesGraphical Interface Systems
Dr. M. Al-Mulhem
Feb. 1, 2008
Display Devices
Display Devices• Vector display
– Draws only lines– Also known as random scan
• Raster display– Discrete grid of elements (frame buffers pixels)– Shapes drawn by setting the “right” elements– Frame buffer scanned (one line at a time) to preserve image– on CRT
• LCD – liquid crystal display– Polarizing light– Crystals react to current
Vector vs. Raster
• Vector – Easy to draw lines– Can display only lines– Refresh time depends on scene complexity– Old fashioned – Very uncommon today
• Raster– Hard to draw smooth lines– Displays a discrete approximation of any shape– Refresh the entire frame buffer– Used practically everywhere
Terminology
• Pixel: Picture element– Smallest accessible element in a picture– Usually rectangular or circular
• Aspect Ratio: – Ratio between physical dimensions of a pixel
(not necessarily 1)
• Dynamic Range: – Ratio between minimal and maximal light
intensity emitted by display pixel.
Terminology (cont).
• Resolution: The maximum number of pixels that can be displayed without overlap on the screen.
• 1024×768 pixels
• Screen Space: A discrete 2D Cartesian
coordinate system of the screen pixels.• Object Space: The 3D Cartesian
coordinate system of the universe.
Hardcopy Devices
• Plotter
• Dot Matrix Printer:
• Laser Printer:
Color Printing Technologies
• Ink Jet– Sprays microscopic dots of ink through small holes to form dots
on paper.
• Thermal Wax– Creates colors by melting and bonding color wax dots onto
special paper.
• Dye Sublimation– Creates continuous-tone by heating dyes until they turn into gas
(sublimate), that fuses into the paper.
• Film Recorder– A camera in front of a designated B&W CRT. RGB channels are
sent one at a time through an appropriate filter.
Standard Input Devices
• Keyboard– For alphanumeric input.
• Mouse/Trackball– Provides relative
movement information.
2D Input Devices
• Joystick– Provides relative movement
information.
• Digitizer/Tablet– Provides absolute position information.
• Touch Screen– A CRT screen that can sense pressure
on its surface.
• Light Pen– Synchronized with the CRT scan, it can
locate a position on screen.
3D Input Devices
• Dataglove– Sensors to detect hand and finger
motions– Used to grasp a virtual objec.t
• Head mounted Display– Used to interact with the
environment.
• Space Ball– Position and orientation is measured
by the pressure applied to the ball.
Image Capture
• Digital Cameras– High resolutions.
• Video Camera– Low resolution.
• Scanner– High resolution.
More Image Capture Devices
• Thermal imaging– Non visible images
• Ultrasound– High frequency sound waves
are converted to form an image.
3D Scanners
• CT / MRI– 3D Imaging
• 3D Range Scanner– Geometry and color texture
digitizer