Binary + Representation of Info (Week 3) Flashcards
Definition : Binary
Digital means “with discrete values” or discrete form such as
numbers like 1 and 0 (on and off).
There is only a limited number of possible values.
Definition : Analog
Values are continuous (with an infinite number of
possible values) such as voltage.
How is Digital Information processed?
To represent any type of information digitally, computers use numbers
To allow information to be processed digitally, analog (real world) information (sound, color, etc.) is converted into a digital format (=> numbers)
Digital results are often converted back to analog, e.g., to present them to users in the real world
How is text represented digitally?
Text is easily represented digitally using a character-encoding scheme that translates characters of an alphabet into numbers.
What are the processes of converting analog to digital and back called?
(en-)coding and decoding
What does it mean to (en-)code and decode information?
To process analog information with a computer, we have to convert analog information into a digital representation.
We translate it to numbers (eventually, to binary numbers that are processed by transistors in a CPU
Definition : Pixel
Picture element
What are the 3 colors used to represent digital pixels?
Red, Green, and Blue (RGB)
What are usually the maximum and minimum values of the RGB color components?
0 to 255
How to increase digital image quality?
More light detectors (pixels) per area
More precise measurement of colour (colour depth)
* Representation could be black/white, grayscale or colour
* Most smartphones/cameras create pixels that can represent 16.8 million different colours (i.e. 256 shades of red, green or blue per pixel or 256 x 256 x 256 = 16.77 million)
How is sound represented digitally?
Signal is measured (sampled) in very short intervals (horizontal chunk). This measurement is the sample rate
The smaller the chunk, the better the sound (similar concept to high resolution in images)
Hertz is x per second or one cycle per second.
The value of each sample (measurement) is stored as a number
The range of possible values for each sample is called bit-depth. Higher bit- depth (=more bits) is better.
How is Bit Depth calculated?
A pixel with a ‘bit depth’ of 1 has two possible values: black or white.
A pixel with a ‘bit depth’ of 8 has 2^8, or 256 possible values.
A pixel with a bit depth of 24 has 2^24, or approx. 16 million possible values.
What affects digital sound quality?
Lower sample rate and smaller range of possible values (bit depth) result in poorer signal (and sound) quality
Higher sample rate and higher range of possible values (bit depth) result in better signal (and sound) quality with the likelihood of reproducing a close example of the true sound.
What are 2 types of compression?
1) Compression Lossless
2) Lossy Compression
Definition : Lossy Compression
Lossy encoding schemes omit information from the data source that humans will likely not perceive to use less file storage – if too much, it degrades quality. This compression type is irreversible.
