28 July 2020

Difference Between Raster Scan and Random Scan

The comparison between a raster scan and a random scan is that lies in the drawing of a picture where the raster points was the electron beam at the entire screen but it is incorporating just one line at a time in the downward direction. While on random scan, the electron beam is guided on just these regions of the screen where the picture actually lies.

Definition of Random scan

The random scan work in a completely different manner and different way to the raster scan where the electron beam is pointed to merely those areas of the screen where the picture is to be drawn. 

Definition of Raster scan

The raster scan is a scanning technique in the graphic monitor where the electron beam is moved along the screen covering one line at a time from top to bottom. The beam intensity is set at high and low both levels as the beam sweeps around the screen to generate a pattern of illuminated spots.

Difference between raster scan and random scan

  • Raster scan is a point plotting device, while in the random scan is a line drawing device.
  • Raster is a sweep in a particular order, while in a random scan draw the image in any order.
  • Raster scan is used for photos.  So that is a reason is why photoshop is a raster editing program. While the random scan is used for text, logos, and letterheads.
  • Raster scan is well suited for the realistic display of scenes containing shading and color patterns, while in the random scan is used for line drawing applications and cannot display realistic shaded scenes.
  • Raster scan is less expansive than a random scan, while a random scan is costlier than a raster scan system.
  • raster scan is poor or less resolution because picture definition is stored as an intensity value. While in random scan high resolution because it stores picture definition as a set of line commands.
  •  Raster scan is suitable for application requiring polygon drawings, while in the random scan is suitable for creating realistic scenes. 
  • The zig-zag line is produced because the plotted value is discrete, while in a random scan smooth line is produced because directly the line path is followed by an electron beam.
  • Random scan is refresh rate is 60 to 80 frames per second, while in random scan refresh rate is 30 to 60 frames per second.
  • Raster scan is stored picture definition in refresh buffer also called a frame buffer. But in the random scan is store picture definition as a set of line commands called a refresh display file.
  • In a raster scan, modification is tough, while in random scan modification if needed is easy.
  • Raster scan in which, for the image, picture rendering, raster scan uses pixels, while in the random scan, a mathematical function is used for image or picture rendering.
  • In a raster scan, shadow mark technology came under this, while in random scan beam penetration technology come under it.

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