Characteristics of Display Adapter

1. Images
• Representation of real world object on digital
display devices is known as an image.
• Object in real world are continuous in nature.
They have Smooth boundary when they are
mapped on monitor screen. They often have
zigzag boundary due to grid structure of
monitor screen.
• As image consists of a rectangular array of
dots. called pixels. The size of image is
specified in terms width x height, in numbers
of pixels

2. Object
• Object are real world entities representing
actual things.
• Objects can be natural like flower, cloud etc or
can be artificial like car, book, etc.
• Objects are represented using three
dimensional coordinate system.

3. Pixel (picture element)
a pixel is the smallest piece of information in an
image.
Pixels are normally arranged in a regular 2D grid,
and are often represented using dots or squares.

4. Pixel (picture element)
Each pixel is a sample of an original image,
where more samples typically provide a more
accurate representation of the original.
The intensity of each pixel is variable; in color
systems, each pixel has typically three or four
components such as red, green, and blue, or cyan,
magenta, yellow, and black.

5. Resolution
• Resolution is the number of rows that appear
from top to bottom of a screen and in turn the
number of pixels or pixel elements that
appear from left to right on each scan line.
• Based on this resolution only the effect of
picture appears on screen.
• In other words greater the resolution greater
will be the clarity of picture. That is resolution
value is directly proportional to clarity of
picture.

6. • Actual resolution is determined by the video
controller.
– Most monitors can operate at several different resolutions.
They are
– 640 X 480
– 800 X 600
– 1024 X 768
– 1152 X 864
– 1280 X 1024
• As the resolution increases, image on the screen gets
smaller.

7. 1) Image Resolution: It refers to pixel spacing. In normal
PC monitor it ranges between 25 to 80 pixels per inch.
2) Screen Resolution: It is the number of distinct pixels in
each dimension that can be displayed.
For example, a computer with a display resolution of
1280 x 768 will produce a maximum of 98,3040 pixels on
a display screen. Each pixel has a unique logical address, a
size of eight bits or more and, in most high-end display
devices, the ability to project millions of different colors.

9. Aspect ratio:
-It is commonly explained as two
numbers separated by a colon (8:9).
This ratio differs in different images,
and in different screens.
Advantages:
Aspect ratio maintains a balance between the appearance of an image on the
screen, means it maintains a ratio between horizontal and vertical pixels. It
does not let the image to get distorted when the aspect ratio is increased.
Another important concept with the pixel resolution is aspect ratio.
Aspect ratio is the ratio between width of an image and the height of an
image.

10. For example
This is a sample image, which has 100 rows and 100 columns. If we wish to
make it smaller, and the condition is that the quality remains the same or
in other ways the image does not get distorted, here is how it happens.
1.Original image

11. Here we can change the rows and columns by maintaining the aspect ratio
in MS Paint.
Then we can see Result : Smaller image, but with the same
balance.

12. ● Example

13. Color Depth
1 bit color
4 bit color
8 bit color
24 bit color
No. of Colors
2
16
256
16,777,216
Color Depth :
 Color "depth" is defined by the number of bits per pixel that can be
displayed on a computer screen.
 Data is stored in bits. Each bit represents two colors because it has a
value of 0 or 1.
 The more bits per pixel, the more colors that can be displayed.
 Examples of color depth are shown in the following table:

14. Determining Color Depth
• Since each bit represents 2 colors, it is easy to work out the
number of colors for the various color depths. The number of
possible colors would be 2 to the power of the number of bits
per pixel:
• A color depth of 4 bits would be 2 times itself 4 times:
2 x 2 x 2 x 2 = 16 colors
• A color depth of of 8 bits would be 2 times itself 8 times:
2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256 colors.
• A color depth of of 24 bits would be 2 times itself 24 times:
2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x2 x 2 x 2 x 2 x 2
x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 16,777,216 colors

15. 1 bit color: no of colors 2 4 bit color : no of colors 16
Image 1 Image 2

16. 8 bit color: no of colors 256 24 bit color: no of colors 16,777,216
Image 3 Image 4

17. Refresh rate :
The refresh rate is the number of times a display's image is repainted or
refreshed per second.
Ex, a 60 Hz refresh rate means the display updates 60 times per second. A
higher refresh rate results in a smoother picture.