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

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

Clip a line segment - cyrus beck line clipping algorithm, How does the Cyru...

How does the Cyrus Beck line clipping algorithm, clip a line segment whether the window is non convex? Solution : see the following figure 13, now the window is non-convex in s

Find out the matrix of projection, Find out the matrix of projection for ca...

Find out the matrix of projection for cavalier projection Answer: Cavalier projection corresponds to tan α = 1, leading to the following matrix.

Key frames -traditional animation techniques, Key Frames -Traditional Anima...

Key Frames -Traditional Animation Techniques The senior artists go and draw the main frames of the animation, after a storyboard has been laid out. These main frames are frame

Importance of multimedia, Importance of Multimedia: Multimedia will help i...

Importance of Multimedia: Multimedia will help in spreading the information age to millions of teachers/learners. Today Multimedia educational computing is fastest raising markets

Line generation algorithms - graphic primitives, Line Generation Algorithms...

Line Generation Algorithms - Graphic Primitives In previous section we have discussed the case of frame buffer, here information regarding the image to be projected upon the

Input and hardcopy devices - 2d shape primitives, Input and Hardcopy Device...

Input and Hardcopy Devices  This section gives a brief introduction to the functioning of some well known input and hardcopy devices. Input devices include keyboard, mouse, sca

C++ programming, self test exercise 17 asked you to overload the operator >...

self test exercise 17 asked you to overload the operator >> and the operator Overload biinary operator + to add pairs according to the rule (a, b) + (c, d) = (a + c, b, + d) overl

Explain about the computer based training, Explain about the Computer Based...

Explain about the Computer Based Training CBT makes use of a computer system to train people in numerous applications. It makes use of self-assessment and multimedia with minim

Define affine transformation, Define Affine transformation?  A coordina...

Define Affine transformation?  A coordinate transformation of the form X= axxx +axyy+bx, y 'ayxx+ayy y+by  is known as a two-dimensional affine transformation. Every of the tra

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