Explain Aspect ratio with example.
Aspect Ratio
The aspect ratio of an image is the ratio of its width to the height.
aspect ratio = $\dfrac{Width}{Height}$
Common video aspect ratios :
| 4:3 | eg. 1440 x 1080 (2k) | the universal video format of the 20th century |
|---|---|---|
| 16:9 | eg. 3840 x 2160 (4k) | universal for HD television, and default for YouTube video |
What is refresh rate in a CRT ?
- The frequency at which a picture is redrawn on the screen
- Redrawing the picture repeatedly by quickly directing the electron beam back over the same ponts to keep the phosphorus glowing.
List and explain any four applications of computer graphics
- IECE
- Image Processing - modify existing pictures such as photographs and TV scans, robotics, Tomography
- Entertainment - Movie Industry, Gaming Industry
- Computer Aided Design (CAD) - design of buildings, automobiles, aircraft - AutoCAD
- Computer Art - cartoon drawing, painting, logo design, Morphing, Electronic Painting
- Education & Training - educational aids, training of aircraft pilot / ship captain.
Give the initial decision parameter equation for Bresenham's line drawing algorithm.
- $P_0=2dy-dx$
Write a note on four interactive graphics input devices.
- Keyboard
- Mouse
- Trackball & Spaceball
- Joystick
- Data Glove
What is the use of Electron gun and deflection plate in a CRT.
- Electron gun is used to emit beam of electrons
- voltage applied to
- horizontal deflection plate controls the horizontal deflection of electronic beam
- vertical deflection plate controls the vertical deflection of electronic beam
Write short note on Persistence and Resolution.
- persistance is the amout of time required for a emitted light from screen to decay 1/10 of its original intensity from the screen
- resolution is the maximum number of points that can be displayed without overlap on a diplay.
What are advantages and disadvantages of DDA line drawing algorithm
- ADV
- simplest algorithm and it does not require special skills for implementation
- It is a faster method for calculating pixel positions than the direct use of equation y = mx + b.
- eliminates the multiplication in the equation
- DIS ADV
- Floating point in DDA algorithm → time-consuming
- End point accuracy is poor
- It doesn’t produce smooth line
Draw Diagram for CRT display
