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 |