Unit-1
Basic Concepts:
most effective way and commonly used way to communicate the processed
information to the user
displays information in form of graphics objects such as pictures, charts, graphs and
diagrams instead of simple text.
pictures/ graphics can be engineering drawing, business graphs, architectural
structure, a single frame, etc.
Allows rotation, translation, scaling and performing various projections
Features like hidden surface removal, shading or transparency
Allows the user to modify object on screen using input devices like keyboard,
mouse or touch-sensitive panel on screen.
close relationship between input devices and display devices.
Pixel:-
A pixel is the smallest unit of a digital image or graphic that can be displayed and
represented on a digital display device.
A pixel is the basic logical unit in digital graphics. Pixels are combined to form a
complete image, video, text, or any visible thing on a computer display.
Rasterization:
The process of determining the appropriate pixels for representing picture or
graphics object is known as rasterization.
Unit-1 1
, Scan Conversion:
The process of representing continuous picture or graphics object as a collection of
discrete pixels is called scan conversion
Display Devices:
Also known as output devices.
Most commonly used output device in a graphic system is a video monitor.
The operation of most video monitors is based on the standard Cathode-Ray-
Tube(CRT).
Cathode-Ray-Tube(CRT):-
Is an evacuated glass Tube
Electron Gun at the rear of the tube produces a beam of electrons which is directed
towards the front of the tube(screen) by high voltage 15000 to 20000 volts.
The negatively charged electrons are then accelerated towards the phosphor
coating at the inner side of the screen by a high positive voltage or by using
accelerating anode.
The phosphor substance gives off light when it is stroked by electrons.
Refresh CRT: When we redraw the picture repeatedly by quickly directing the
electron beam back over the same points just to keep the phosphor glowing this
type of display is called refresh CRT
The control grid voltage determines the velocity achieved by the electrons before
they hit the phosphor.(how many electrons are actually in the electron beam)
The focusing system concentrates the electron beam so that the beam converges
to small point when it hits the phosphor coating.
Unit-1 2
, The deflection system of the cathode-ray-tube consists of two pairs of parallel
plates, referred to as the vertical and horizontal deflection plates.
The voltage applied to vertical plates controls the vertical deflection of the
electric beam and the same for horizontal.
Aqueous graphite collects the secondary electrons. To maintain the CRT in
electrical equilibrium, it is necessary to collect the secondary electrons.
Architecture of Vector Display:
Unit-1 3
Unit-1
Basic Concepts:
most effective way and commonly used way to communicate the processed
information to the user
displays information in form of graphics objects such as pictures, charts, graphs and
diagrams instead of simple text.
pictures/ graphics can be engineering drawing, business graphs, architectural
structure, a single frame, etc.
Allows rotation, translation, scaling and performing various projections
Features like hidden surface removal, shading or transparency
Allows the user to modify object on screen using input devices like keyboard,
mouse or touch-sensitive panel on screen.
close relationship between input devices and display devices.
Pixel:-
A pixel is the smallest unit of a digital image or graphic that can be displayed and
represented on a digital display device.
A pixel is the basic logical unit in digital graphics. Pixels are combined to form a
complete image, video, text, or any visible thing on a computer display.
Rasterization:
The process of determining the appropriate pixels for representing picture or
graphics object is known as rasterization.
Unit-1 1
, Scan Conversion:
The process of representing continuous picture or graphics object as a collection of
discrete pixels is called scan conversion
Display Devices:
Also known as output devices.
Most commonly used output device in a graphic system is a video monitor.
The operation of most video monitors is based on the standard Cathode-Ray-
Tube(CRT).
Cathode-Ray-Tube(CRT):-
Is an evacuated glass Tube
Electron Gun at the rear of the tube produces a beam of electrons which is directed
towards the front of the tube(screen) by high voltage 15000 to 20000 volts.
The negatively charged electrons are then accelerated towards the phosphor
coating at the inner side of the screen by a high positive voltage or by using
accelerating anode.
The phosphor substance gives off light when it is stroked by electrons.
Refresh CRT: When we redraw the picture repeatedly by quickly directing the
electron beam back over the same points just to keep the phosphor glowing this
type of display is called refresh CRT
The control grid voltage determines the velocity achieved by the electrons before
they hit the phosphor.(how many electrons are actually in the electron beam)
The focusing system concentrates the electron beam so that the beam converges
to small point when it hits the phosphor coating.
Unit-1 2
, The deflection system of the cathode-ray-tube consists of two pairs of parallel
plates, referred to as the vertical and horizontal deflection plates.
The voltage applied to vertical plates controls the vertical deflection of the
electric beam and the same for horizontal.
Aqueous graphite collects the secondary electrons. To maintain the CRT in
electrical equilibrium, it is necessary to collect the secondary electrons.
Architecture of Vector Display:
Unit-1 3
