Vector Scan Display

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 • CRT have 2 kind of display technique

1) Vector scan Display

2) Raster scan Display

• We will here First discuss about Vector scan Display.

A) Vector Scan Display.

1) Vector Scan Display is a technique used for producing images on the screen.

2) There different names for Vector Scan Display as follows:

a) Vector Scan Display

b) Random scan Display

c) Calligraphic Display

d) Stroke - Writing Display

3) In this technique electron beam is only directed to the area on the screen where picture is to be drawn.


4) Above image is one of the popular diagram to depict the working of Vector Scan Display.

5) Here you can see, electron beam is working like a pencil on the screen and only beams in a particular area only not on the whole screen point to be noted.

6) The picture is constructed out of a sequence of straight-line segments. Each line segment is drawn on the screen by directing the beam to move from one point on the screen to the next, where its x & y coordinates define each point.


7)  As shown in Fig., vector scan CRT display directly traces out only the desired lines on CRT i.e. If we want a line connecting Point A with Point B on the vector graphics display, we simply drive the beam deflection circuitry, which will cause beam to go directly from Point A to B. 

8) If we want to move the beam from point A to Point B without showing a line between points, we can blank the beam as we move it.

9) To move the beam across the CRT, the information about both, magnitude and direction is required. This information is generated with the help of vector graphics generator.

10) In vector displays beam is deflected from end point to end Point, hence this technique is also called random scan. In this the picture can be draw in terms of line, one at a time. The refresh rate depends on the number of lines to be displayed.

11) Let's see Advantage and disadvantage of Vector Scan Display 

1) Advantage

• High resolution then Raster scan Display

=> Because Vector Scan Display only focuses on drawing in particular region only rather than whole screen.

• produces smooth line.

=> This is something why Vector Scan Display is use for.

• Needs less memory to store picture definition.

=> Because it only stores points and coordinate information only 

2) Disadvantage

• Can't draw Realistic image

=> Because as we saw earlier it only stores information of coordinate not about colors that is picture Element (pixel)

• Limitation on color to be displayed

=> Particularly uses only 4 colors.


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

 

 

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