Difference between Raster and Random Scan Display
Raster Scan Display
Raster Scan Display basically employs a Cathode Ray Tube (CRT) or an LCD panel for display. The CRT works just like the picture tube of a television set. The Raster Scan Display viewing surface is coated with a layer of arrayed phosphor dots. At the back of the CRT is a set of electron guns (cathodes) that produce a controlled stream of electrons that says electron beam. The phosphor material emits light when struck by these high-energy electrons.
Random Scan Display
In Random Scan Display, the electron beam is directed straightway to the particular points of the screen where the image is produced. Random Scan Display generates the image by drawing a set of random straight lines. It is much in the same way one might move a pencil over a piece of paper to draw an image. The drawing strikes from one point to another, one line at a time. That’s why this technique also says Vector Scan Display.
Raster Scan Display vs Random Scan Display
| 1. Raster Scan Display's resolution is low | 1. Random Scan Display's resolution is high |
| 2. Solid pattern is easy to fill | 2. Solid pattern is tough to fill |
| 3. In Raster Scan Display, Whole screen is scanned | 3. In Random Scan Display, Only screen with view on an area is displayed |
| 4. Refresh rate does not depend on the picture | 4. Refresh rate depends or resolution |
| 5. The electron beam is swept across the screen, one row at a time, from top to bottom | 5. The electron beam is directed only to the parts of screen where a picture is to be drawn |
| 6. In Raster Scan Display, Screen points/pixels are used to draw an image | 6. In Random Scan Display, Mathematical functions are used to draw an image |
| 7. Raster Scan Display uses interlacing method | 7. Random Scan Display does not use interlacing method. |
| 8. Raster Scan is mainly used in photos like JPG,PNG,GIF File Format | 8. Random Scan system is mainly used in HD images like SVG File Format |
| 9. Raster Scan Display is less expensive than Random Scan Display | 9. Random Scan Display is more expensive than Raster Scan Display |
| 10. Example: TV | 10. Example: Pen Plotter |