Computer Graphics Unit 1 Quiz

Basic Elements of Computer Graphics

• Pixel, derived from "Picture Element," is the smallest unit of a digital image on displays like LCD or CRT.
• Images consist of thousands to millions of pixels, forming a compact grid viewed as a whole.
• Each pixel has specific color and brightness values, which combine to create the final image appearance.

Megapixel

• A megapixel equals one million pixels, often used to measure digital camera resolution and display quality.
• The resolution of images can be calculated by multiplying width by height in pixels.
• Example: A 1080p video resolution translates to 1920 × 1080 pixel count, totaling 2,073,600 pixels or approximately 2MP.

PPI and DPI

• PPI (Pixels Per Inch) measures pixel density on a digital display, while DPI (Dots Per Inch) measures printed dots in physical images.
• PPI reflects image quality on-screen; DPI is relevant for print quality.

Resolution

• Resolution refers to the pixel count on display screens, with two types: Image Resolution and Screen Resolution.
• Image Resolution pertains to pixel spacing within an image; for instance, an 800 x 600 resolution means 480,000 pixels total.
• Screen Resolution indicates the total pixel count on a display; a 3840 x 2160 (4K UHD) resolution has 8,294,400 pixels.

Dot Pitch

• Dot pitch is the distance between adjacent dots of the same color on a screen, influencing sharpness and resolution.
• Typical dot pitch ranges from 0.25 mm to 0.40 mm; smaller dot pitch yields higher clarity.

Aspect Ratio

• Aspect ratio represents the relationship between pixel width (X) and height (Y) in the format X:Y, defining image proportions.

Raster Scan Display

• Employs a CRT or LCD with a phosphor-coated surface and uses electron beams to create images by scanning across the display.
• The process includes Horizontal Retrace (returning to leftmost position) and Vertical Retrace (moving to start of the next frame).

Refresh Rate

• Refresh Rate measures how often a screen redraws; an unstable image results from the brief glow time of phosphors after being struck by an electron beam.
• Typically, refresh rates are set between 30 to 60 Hz.

Color CRT Monitor

• Combines primary colors—red, green, and blue—to produce a wide color spectrum.
• Techniques include:
  • Beam Penetration Method: Uses electron beam penetration to excite different phosphors, resulting in limited color production (four colors only).
  • Shadow-Mask Method: Enables more color accuracy on raster scan monitors without the depth criteria of beam penetration.

Applications of Computer Graphics

• Computer Art: Utilizes graphics for creating artwork, logos, and cartoons.
• Computer Aided Drawing: Facilitates design in architecture, vehicles, and aircraft.
• Presentation Graphics: Summarizes data visually for reports using charts and graphs.
• Entertainment: Vital for animations in movies, video games, and television shows.
• Education: Enhances learning through interactive educational models.
• Training: Employs simulators for efficient skill development.
• Visualization: Aids professionals in interpreting large data sets across various industries.
• Image Processing: Enhances existing images for better clarity and understanding.
• Medical Imaging: Non-invasive technologies like MRIs and CAT scans for internal examination.

This quiz covers the basic elements of computer graphics, including its applications and hardware architecture. It also delves into the concept of pixels and their significance in image display on various monitors. Test your understanding of these foundational concepts in computer graphics.