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

Depth-buffer (or z-buffer) method , Depth-buffer (or z-buffer) Method ...

Depth-buffer (or z-buffer) Method  Z-buffer method is a fast and easy technique for specifying visible-surfaces. Z-buffer method is also termed to as the z-buffer method, as

Finding where the ball hits a segment, You will write a two-dimensional pre...

You will write a two-dimensional precursor of the three-dimensional bouncing ball simulation that is one of your choices for a ?nal project. This involves adding functions to your

What is surface patch, What is surface patch?  A single surface element...

What is surface patch?  A single surface element can be explained as the surface traced out as two parameters (u, v) take all possible values between 0 and 1 in a two-parameter

Electronic encyclopedia, Electronic Encyclopedia : This is the applica...

Electronic Encyclopedia : This is the application of multimedia for the creation of an encyclopedia along with millions of entries and hypertext cross references covering a br

Unrepresentative vertex normals - modeling and rendering, Unrepresentative ...

Unrepresentative vertex normals - Modeling and Rendering Calculated vertex normals may not adequately present the surface's geometry. For illustration, if we calculate vertex

Gif file compression, GIF File Compression The Graphic Interchange Form...

GIF File Compression The Graphic Interchange Format file format utilizes a relatively basic form of file compression which squeezes out inefficiencies within the data storage w

Simulating accelerations - computer animation, Simulating Accelerations - C...

Simulating Accelerations - Computer Animation In previous block, we have seen the dominance and function of mathematics in computer graphics and now, we will undertake the invo

What is shearing, What is shearing?  The shearing transformation actua...

What is shearing?  The shearing transformation actually slants the object with the X direction or the Y direction as needed.ie; this transformation slants the shape of an obje

Definitions of hypermedia, Definitions of Hypermedia It is a term ...

Definitions of Hypermedia It is a term created through Ted Nelson in the year 1970. It utilized as a logical extension of the term hypertext, wherein graphics, video, audi

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