GRAPHICS AND IMAGE PROCESSING
RAVI YASAS JAYASUNDRA
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Plasma panel display
This is a flat panel display consist of two glass panels each with parallel electrodes deposited on their surface.
Electrodes covered with a dielectric layer. The long electrodes are stripes of electrically conducting material that also lie between the glass plates, in front of and behind the cells. As can be seen in the illustration, the electrodes are covered by an insulating protective layer. The transparent display electrodes are mounted in front of the cell, along the front glass plate. Control circuitry charges the electrodes that cross paths at a cell, creating a voltage difference between front and back. The "address electrodes" sit behind the cells, along the rear glass plate, and can be opaque. To erase a cell all voltage is removed from a pair of electrodes. With flow of electricity (electrons), some of the electrons strike mercury particles as the electrons move through the plasma, momentarily increasing the energy level of the molecule until the excess energy is shed.
It has a high contrast ratio because it is used over 16 million colors.
Can be used for large screen sizes.
This type of display has 160 degree viewing angle.
It is very thin than CRT display.
Does not perform well at high altitudes above 2km.
Uses more power than LCDs.
Has shorter lifespan than LCDs.
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Liquid Crystal Display (LCD)
This is used light modulating properties of liquid crystals.
This is made of two sheets of a flexible polarizing material with a layer of liquid crystal solution.
This type of display does not refresh like CRT.
An electric current passed through the liquid causes the crystals to align so that light cannot pass through them.
Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.
Very thin, compact and light weight.
Very low power consumption.
No geometric distortion at the native resolution.
Can be created small and large size of displays with high resolutions (Theoretically no limit).
Images are perfectly sharp and produce very bright images due to high peak intensity.
Low refresh rate
Slow response times.
Limited viewing angle.
The aspect ratio and resolution are fixed.
Low contrast than CRT due to a poor black level.
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LED Backlit Display
These types of displays use LED as a light resource.
These type of displays are not self-illuminating.
There are few types of Backlit LED displays.
1. RGB LED backlighting
2. An edge backlight with white LEDs
3. A flat backlight based on white LEDs.
It gives better dynamic contrast.
Have a long lifespan.
Uses less power.
Extremely thin (less than 0.5inch displays are available).
It has fast response.
This types of displays are more expensive.
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Plotter is a printer that is used to print vector graphics.
This is not like a simple printer, it is used automated pens to draw.
There are different types of plotters.
1. Drum plotter
2. Flatbed plotter
3. Electrostatic plotter
Now a days there are cutting plotters also in the market which can be used to print and cut.
HP is the leading plotter vendor in the world.
This is widely used to draw in engineering field like to CAD and CAM.
Can be used to large size of printings like posters, banners etc.
Can print not only simple papers but also hard papers like weather resistance papers.
Have a good contrast than normal printers.
Plotters are very expensive than printers.
It gets lot of time to print.
Printing materials are expensive.
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Head Mounted Display
This is a simple helmet which includes display with lenses and semitransparent mirrors.
Real pictures or pictures generated by a computer can be seen through this device.
Modern HMD devices are come with LCD display. Because this should be light weighted and compact.
Very rarely it comes with other display technologies like LED, EPD (Electrophoretic Displays), VRD (Virtual Retinal Displays), and Plasma etc.
Many of these HMD devices come with integrated speakers or headphones.
HMDs widely used in video games, simulators, military purposes, medicine and engineering areas.
It can make a better simulation environment than other equipment.
Even when you are on the bed, you can wear this. It need not a relevant position to wear.
It is easy to handle because of its compactness.
It may be caused to headache and your eyes can be harmed when you use it a long time.
These devices are expensive.
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This is the way that you can get a real experience of hard situations without any harm.
In this technology use HMD (Head Mounted Display) which is giving a 3D images.
User can get the simulating experience using sound, images and videos.
Now a days there is a device called ‘Haptic Device’ to get the further experience of touch and force feedback enabled environment.
This technology is developed by scientists and computer programmers.
Can be create 3D situations.
Can be used for simulating purposes
1. To train doctors
2. To get the real experience of gaming
3. To train soldiers using battle situations.
This is high costly technology.
It is hard to use in home.