Computer Graphics Unit 1 & 2 Overview

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Questions and Answers

What is the standard aspect ratio for PCs?

4:3 (correct)

3:2

5:4

16:9

Which display resolution corresponds to the aspect ratio of 5:4?

1920 × 1080

640 × 480

1024 × 768

1280 × 1024 (correct)

What is the main purpose of display technology?

To manage data storage

To display information visually (correct)

To connect multiple devices

To enhance data processing speed

Which component of the Cathode Ray Tube is primarily responsible for emitting electrons?

Electron Gun (D) Signup and view all the answers

What does the Focusing system in a CRT do?

Creates a clear picture by focusing electrons. (C) Signup and view all the answers

Which of the following is NOT a type of display device mentioned?

Organic Light Emitting Diode (B) Signup and view all the answers

What function do the Horizontal and Vertical Deflection Plates serve in a CRT?

To guide the path of the electron beam. (C) Signup and view all the answers

Which of the following resolutions supports the 16:9 aspect ratio?

1920 × 1080 (D) Signup and view all the answers

What is the full form of the term 'PIXEL'?

Picture Element (D) Signup and view all the answers

What determines the number of megapixels in an image?

The width multiplied by the height of the image (D) Signup and view all the answers

How many pixels are there in one megapixel?

1,000,000 pixels (A) Signup and view all the answers

What does PPI measure in digital images?

Pixels Per Inch (A) Signup and view all the answers

Which of the following statements is true regarding DPI?

It describes the quality of printed images. (D) Signup and view all the answers

Which pixel structure feature is essential for the perception of images?

The distance between pixels (B) Signup and view all the answers

In the context of video resolution, what does 1080p indicate?

The pixel count is 1,920 x 1,080 (A) Signup and view all the answers

What is the primary distinction between PPI and DPI?

PPI is for digital images, while DPI is for printed images. (A) Signup and view all the answers

What initiates the operation of a CRT display?

The electron gun emitting a beam of electrons (A) Signup and view all the answers

How does the electron beam produce an image on the screen?

By directing beams to specific positions and faintly glowing them (D) Signup and view all the answers

What is the primary factor that determines the amount of memory required for a frame buffer?

The color depth per pixel (B) Signup and view all the answers

What is the purpose of the frame buffer in a raster scan display?

To store the picture and enable redrawing (B) Signup and view all the answers

What happens during the horizontal retrace in a raster scan display?

The electron beam returns to the leftmost position of the line (A) Signup and view all the answers

In which type of display does the electron beam draw one row of the screen at a time?

Raster Scan Display (A) Signup and view all the answers

What does a higher refresh rate indicate?

The electron beam sweeps the screen more times per second (A) Signup and view all the answers

Which statement is true regarding the resolution of Raster Scan Displays compared to Random Scan Displays?

Random Scan Displays have higher resolution than Raster Scan Displays (C) Signup and view all the answers

What is the refresh rate commonly associated with Raster Scan Displays?

60 to 80 frames per second (D) Signup and view all the answers

What is the effect of the phosphor material fading after being struck by the electron beam?

It causes the image to become unstable over time (A) Signup and view all the answers

Which of the following is the correct formula to calculate the memory required for a frame buffer?

Memory in MB = (X-resolution × Y-resolution × Bit-per-pixel) / (8 × 1024 × 1024) (A) Signup and view all the answers

Which of the following best describes the raster scan process?

The beam systematically scans left to right and top to bottom (A) Signup and view all the answers

What type of memory area does a Random Scan Display use to store picture definitions?

Refresh Display File (A) Signup and view all the answers

Which characteristic of the phosphor material impacts the screen's image quality?

The energy of the emitted electrons (B) Signup and view all the answers

Which of the following statements accurately describes a characteristic of Random Scan Displays?

They generate images through drawing individual straight lines (D) Signup and view all the answers

Which type of scan display uses an electron beam directed to the entire screen?

Raster Scan Display (D) Signup and view all the answers

What is one key component of a shadow mask CRT?

A shadow mask with tiny holes (B) Signup and view all the answers

How many different electron guns are used in a shadow mask CRT?

Three (A) Signup and view all the answers

Which method can produce millions of colors?

Shadow Mask Method (C) Signup and view all the answers

What is a disadvantage of the beam penetration method compared to the shadow mask method?

Lower number of colors displayed (D) Signup and view all the answers

How does a shadow mask affect picture quality?

Adds realism with shadow effects (C) Signup and view all the answers

In relation to cost, how does the beam penetration method compare to the shadow mask method?

It is less expensive (A) Signup and view all the answers

Which aspect of color representation is more limited in the beam penetration method?

Range of colors (C) Signup and view all the answers

What is a characteristic of the resolution provided by the shadow mask method?

Low resolution (B) Signup and view all the answers

Study Notes

Basic Elements of Computer Graphics

Computer graphics encompass visual representation of data through images and animations.
Applications include computer-aided design (CAD), medical imaging, video games, and simulations.

Pixel

Pixel (Picture Element) is the smallest unit of a digital image.
Each pixel holds specific color and brightness values, forming a grid when combined.
The resolution of digital displays is defined by the number of pixels.

Megapixel

One megapixel (MP) equals one million pixels.
Often used to describe camera resolution and digital display quality.
To calculate total pixels in an image: width × height (e.g., 1920 × 1080 = 2,073,600 pixels).

PPI and DPI

PPI (Pixels Per Inch) measures digital image sharpness on screens.
DPI (Dots Per Inch) measures printed image quality.
PPI indicates display quality, while DPI refers to printing ink dots.

Display Devices in Computer Graphics

Output devices represent visual information, known as Video Display Units (VDU).
Rising demand for high-quality displays drives technology development.

Types of Display Devices

Cathode Ray Tube (CRT)
Color CRT Monitor
Liquid Crystal Display (LCD)
Light Emitting Diode (LED)
Direct View Storage Tubes (DVST)
Plasma Display
3D Display

Cathode Ray Tube (CRT)

CRT technology was common in older monitors and televisions.
Works by generating images using electron beams focused on phosphor-coated screens.
Essential components: Electron Gun, Control Electrode, Focusing System, Horizontal & Vertical Deflection Plates.

Raster Scan Display

Uses CRT or LCD to display images by scanning from top to bottom.
Employs arrays of phosphor dots emitting light when hit by electrons.
Refresh Rate is crucial to stabilize images—monitors refresh multiple times per second via Horizontal and Vertical Retrace.

Frame Buffer

A dedicated memory area that stores intensity values of displayed images.
Memory requirement is calculated based on resolution and color depth.

Random Scan Display

Electron beam directs to specific screen points to create images by drawing lines.
High resolution achieved by storing images as line-drawing commands.

Comparison: Raster Scan vs. Random Scan Display

Raster Scan: Electron beams from top to bottom, less resolution and cost-effective.
Random Scan: Directs the beam where needed, providing high resolution but at a higher cost.

Shadow Mask Technology

Used in CRT displays, allows for color representation using three electron guns (red, green, blue).
Activates specific color dots on-screen through directed beams.
Offers high image realism and a broader range of colors compared to beam penetration methods.

Beam Penetration vs. Shadow Mask

Beam Penetration: Suitable for Random Scan; cheaper but limited to fewer colors and poorer image quality.
Shadow Mask: More expensive; provides millions of colors and high-quality images with realistic effects.

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Description

This quiz covers the basic elements and applications of computer graphics, including the architecture of display devices and input/output technologies. Test your knowledge on pixels and how they function in the realm of computer graphics.