Crt - cathode ray tube, Computer Graphics

Assignment Help:

CRT - Cathode Ray Tube

  • Electron gun is used to send an electron beam aimed at a particular point on the screen. Deflection system is used to make the beam strike the screen on a precise point.
  • When electron beam strikes the screen, coated phosphor emits light due to the natural phenomenon called phosphorescence. Output decays rapidly approximately within 10 - to 60 microseconds.
  • As a result of this decay, the entire screen must be refreshed at least 30-60 times per second. This is called the refresh rate. If the refresh rate is low, screen will tend to flicker.
  • CFF (Critical Fusion Frequency) is the minimum refresh rate needed to avoid flicker. It depends on the persistence of the phosphors and the human vision system.
  • Electron beam traces out a path on the screen, hitting each pixel once per cycle. Tracing out of the entire picture once is called a cycle. In case of a raster scan display we call the horizontal path of the beam a scan line. In case of random scan display, the path is a directed set of line segment, which are called vector lines.
  • On a raster scan display, refresh rate is fixed as mentioned above. On a vector display, a scan is in the form of a list of directed line segments to be drawn, so the time to refresh is dependent on the length of the display list. For small and simple object displays, some kind of delay is introduced to avoid un-necessary refreshing of the screen.
  • In color CRT, shadow-mask method is most common since it produces a wide range of colors. In this method, each pixel consists of a group of three phosphor dots (one each for red, green, and blue), arranged in a triangular form called a triad. The shadow mask is a grid structure with one hole per pixel. To excite one pixel, three electron guns are used one for each of red, green, and blue. Each gun fires its electron stream through the hole in the mask to hit that pixel.

Related Discussions:- Crt - cathode ray tube

Uncompressed and common audio format, Uncompressed / Common Audio Format ...

Uncompressed / Common Audio Format There is one main uncompressed audio format: PCM. It is generally stored like a .wav on Windows. WAV is file format which is flexible and des

Scan conversion, what are the advertising effects of scan conversion

what are the advertising effects of scan conversion

Objectives of three dimensional transformations, Objectives  of Three dimen...

Objectives  of Three dimensional transformations explain basic 3D transformations-translation, rotation, scaling, shear and reflections-applied to objects in space; ex

Write a c program to create a window of specified size, Write a C program t...

Write a C program to create a window of specified size and position and draw the following objects with dimensions of your choice, to fit within the window.   (a) A point  (b) A

Implement cohen sutherland and liang barsky algorithm, Implement Cohen Suth...

Implement Cohen Sutherland and Liang Barsky line clipping algorithms in C-language.  Test your code for line segments with end points falling in various regions.

Polygon representation methods - modeling and rendering, Polygon Representa...

Polygon Representation Methods - Modeling and Rendering Any scene to be created by computer graphics may include a variety of objects, a few of them natural and manmade. Hence

Structural links, Structural Links: The information contained inside the h...

Structural Links: The information contained inside the hypermedia application is classically organized in several suitable fashions. This organization is represented by using stru

Assumptions for area subdivision method, Assumptions for Area Subdivision M...

Assumptions for Area Subdivision Method a) ¾   Plane of projection is z=0 plane b) ¾ Orthographic parallel projections c) ¾   Direction of projection as d= (0,0,-1) d

High level techniques (motion generalized), High level techniques (motion g...

High level techniques (motion generalized) Techniques utilized to explain general motion behavior of any of graphic object, such techniques are algorithms or models utilized to

Rotation about z-axis - transformation for 3-d rotation, Rotation about z-a...

Rotation about z-axis - Transformation for 3-d rotation Rotation about z-axis is explained by the xy-plane. Suppose a 3-D point P(x,y,z) be rotated to P'(x',y',z') along with

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd