Difference between Raster and Random Scan Display

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 A) Raster Scan Display



1) The Architecture of Raster Scan Display consist of a display controller, Keyword, Mouse, CPU, Video controller, Refresh buffer and CRT.

2) Refresh buffer is a temporary place where picture informations is stored in order to refresh the screen.

3) The video controller Reads the refresh buffer and produces the actual image on the screen

4) The Picture information is stored in the form of 0's and 1's in the refresh buffer.

5) So Information of picture is stored in refresh buffer and it is read by Video controller as in above architecture the output will be letter 'T', But How is picture displayed by video controller?

6) It is done through scanning one scanline at a time, from top to bottom and then back to top.


7) Raster Scan Display is mainly used in JPG, GIF, PNG image format.

8) when Raster image is Zoomed or made bigger in size in layman terms, the image will be distorted or we will get a blur image, Because they are made up of Pixel i.e (grid of Rows and Columns) if you try to increase the resolution then of course it will be distorted.



B) Random Scan Display


1) In Random scan Display architecture we have the same components only, but the only difference here is, in format of picture information stored in refresh buffer.

2) The information stored in refresh buffer is the set of instructions like coordinate of line, move instruction, make line instruction as we have in assembly language.

3) Here image is drawn directly through coordinate points on the screen, no scanning is done here.

4) Random Scan Display is used High Quality images, in SVG, the size is rescaleable like Logos.

5) Random is also known as Vector Scan Display.



• From the above image you can clearly identify the difference between Raster and vector Scan Display.

• Can Even check it by Zooming in and out.


*You can leave a comment if you have doubt in it.




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