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Consider three different raster systems with resolutions of 640 x 480, 1280 x 1024, and 2560 x 2048.

a) What size is frame buffer (in bytes) for each of these systems to store 12 bits per pixel?

Because eight bits constitute a byte, frame-buffer sizes of the systems are as follows:

640 x 480 x 12 bits / 8 = 450KB;

1280 x 1024 x 12 bits / 8 = 1920KB;

2560 x 2048 x 12 bits / 8 = 7680KB;

b) How much storage (in bytes) is required for each system if 24 bits per pixel are to be stored?

Similarly, each of the above results is just doubled for 24 (12×2) bits of storage per pixel.

Consider two raster systems with the resolutions of 640 x 480 and 1280 x 1024.

a) How many pixels could be accessed per second in each of these systems by a display controller that refreshes the screen at a rate of 60 frames per second?

Since 60 frames are refreshed per second and each frame consists of  640 x 480 pixels, the access rate of such a system is (640 x 480) * 60 = 1.8432 x 10⁷ pixels/second.

Likewise, for the 1280 x 1024 system, the access rate is (1280 x 1024) * 60 = 7.86432  x 10⁷ pixels/second.

 b) What is the access time per pixel in each system?

According to the definition of access rate, we know that the access time per pixel should be 1/(access rate). Therefore, the access time is around 54 nanoseconds/pixel for the 640 x 480 system, and the access time is around 12.7 nanoseconds/pixel for the 1280×1024 system.

 Consider a raster system with the resolution of 1024 x 768 pixels and the color palette calls for 65,536 colors. What is the minimum amount of video RAM that the computer must have to support the above-mentioned resolution and number of colors?

Recall that the color of each pixel on a display is represented with some number of bits. Hence, a display capable of showing up to 256 colors is using 8 bits per pixels (i.e. “8-bit color”).

Notice first that the color palette calls for 65,536 colors. This number is but 2¹⁶ , which implies that 16 bits are being used to represent the color of each pixel on the display. The display’s resolution is 1024 by 768 pixels, which implies that there is a total of 786,432 (1024 × 768) pixels on the display. Hence, the total number of bits required to display any of 65,536 colors on each of the screen’s 786,432 pixels is 12,582,912 (786,432 × 16). Dividing this value by 8 yields an answer of 1,572,864 bytes. Dividing that value by 1,024 yields an answer of 1,536 KB. Dividing that value by 1,024 yields an answer of 1.5 MB.

Explain the merits and demerits of Penetration techniques.

The merits and demerits of the Penetration techniques are as follows;

[1] It is an inexpensive technique

[2] It has only four colors

[3] The quality of the picture is not good when it is compared to other techniques

[4] It can display color scans in monitors

 Explain the merits and demerits of DVST.

The merits and demerits of direct view storage tubes [DVST] are as follows;

[1] It has a flat screen

[2] Refreshing of screen is not required

[3] Selective or part erasing of screen is not possible

[4] It has poor contrast

[5] Performance is inferior to the refresh CRT.

 Explain the merits and demerits of Plasma panel display.

ADVANTAGES:

[1] Refreshing is not required

[2] Produce a very steady image free of Flicker

[3] Less bulky than a CRT.

DISADVANTAGES:

[1] Poor resolution of up to 60 d.p.i

[2] It requires complex addressing and wiring

[3] It is costlier than CRT.

 What is the difference between impact and non-impact printers?

 Impact printers press formed character faces against an inked ribbon on to the paper.

 A line printer and dot-matrix printer are examples.

Non-impact printer and plotters use Laser techniques, inkjet sprays, Xerographic process,

electrostatic methods and electro thermal methods to get images onto the papers.

Examples are: Inkjet/Laser printers.

 What is the features of Inkjet printers?

Features:

a] They can print 2 to 4 pages/minutes.

b] Resolution is about 360d.p.i. Therefore better print quality is achieved.

c] The operating cost is very low. The only part that requires replacement is ink cartridge.

d] 4 colors cyane, yellow, majenta, black are available.

 What are the advantages of laser printers?

1] High speed, precision and economy.

2] Cheap to maintain.

3] Quality printers.

4] Lasts for longer time.

5] Toner power is very cheap.

 What is the advantages of electrostatic plotters?

1] They are faster than pen plotters and very high quality printers.

2] Recent electrostatic plotters include a scan-conversion capability.

3] Color electrostatic plotters are available. They make multiple passes over the paper to plot color pictures.

Differentiate emissive and non emissive displays.

Emissive display displays are devices that convert electrical energy into light.

Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns.

 List some 3D viewing devices.

1. Stereoscopic systems
2. Virtual reality systems

      What is the role of a video controller?

It is the one of the component of an interactive raster scan system. It is used to control the operation of the display device by accessing the frame buffer to refresh the screen.

Define Graphics controller /Display controller/Display processor.

The purpose of the display processor is to free the CPU from graphic chores. A major task of the display processor is digitizing a picture definition given in an application program into a set of pixel intensity values for storage in the frame buffer.

 What do you mean by scan conversion?

A major task of the display processor is digitizing a picture definition given in an application program into a set of pixel intensity values for storage in the frame buffer. This digitization process is called scan conversion.