Code Definition:
A predetermined system of communication between two parties. In communications, converting a piece of information (for example, a letter, word, or phrase) into another form of representation. For our purposes we will think of a code as a combination of digits and a base.

A one bit message: Computers express information with a very simple code that is made up of only positive and negative electronic pulses. Each positive and negative signal is called a "Bit".


Binary Code:
Made up of only zeros and ones, and used by computers to stand for letters and digits. A binary system has only two possible values, we say that a bit has a code base of two.

 
1 Bit Message
  
0 1
Positive (+) Negative (-)
On Off
Black White

A 2 bit message can produce 4 possible messages: (2^2nd power) or 1,0 or 0,1 or 0,0 or 1,1

A 3 bit message can produce 8 possible messages: (2^3rd power)


Rule 1 of codes: # of Digits = # of possible messages

Example: 3 digits (base 2) = 8 possible messages


Binary Code Odometer
# of digits
# of possible messages
1 Digit (bits)
2
2 Digits (bits)
4
3 Digits (bits)
8
4 Digits (bits)
16
8 Digits (bits)
256
10 Digits (bits)
1,024
12 Digits (bits)
4,096
16 Digits (bits)
32,767

 


Other Codes
System Base Typical Expressions
Binary 2  
Morse 4  
Decimal 10  
Hexadecimal 16  
Roman Alphabet 26 a,b,c,d,e,f,g,h.....,z
ASCII 128 a,b,c,d / A,B,C,D / 0-9 / *,",$,#

Code Basics
System Base 1 2 4
Binary 2 2 4 16
Morse 4 4 16 256
Decimal 10 10 20 10,000
Roman 26 26 676 456,976
ASCII 128 128 16,348 268,435,456

 


Rule 2 of Codes: A lower base will require more digits to express a message than a higher code base.

Example: 2^16 power = 65,536 = 256^2th power


8 Bit Images:(8 bits of color data per channel)
A bit can have one of two states: On or Off, Black or White, etc. This is the basic concept of binary arithmetic. 8 bits compose a "byte". Most of the world operates with 8 bit images and this is the default workspace for most digital images.

A byte (8 bits) can represent 256 states (2^8th power).
Screen graphics use a color mode of R,G,B. Each image has a red channel, a green channel, and a blue channel. Each of these discreet channels has by itself (assuming we are using an 8 bit image) 256 possibilities (shades of gray). These channels can be mixed to create 16.7 million colors (256 x 256 x 256).

10 Bit Images:(10 bits of color data per channel)
Each component color channel (R,G,B) has 1,024 (remember: 2^10th power) possible shades of gray. These channels can be mixed to create 10,733,741,824 (1024 x 1024 x 1024). These images begin to get exponentially larger.

16 Bit Images:(16 bits of color data per channel)
Each component color channel (R,G,B) has 65,536 (remember: 2^16th power) possible shades of gray. (65,536 x 65,536 x 65,536). Do the math to calculate how much color information is available.

The problem with these images is as the color space grows exponentially so does the file size.

8 bit image in RGB color space. 256 possibilities for each of the Red, Green, and Blue channels.

16.7 million color possibilities

1 Bit image.

A total of two colors (black or white)

A grayscale 8 bit image with One channel.

256 shades of gray.

The Red Channel from the first image. 256 possible shades of red.

Typically the red channel contains the greatest range of contrast values found within the image. The brightest and darkest values will be found in the red channel.

Red = Contrast

The Green Channel from the first image. 256 possible shades of green.

The green channel is typically where the best "high-frequency detail" is located within the image (edges that display significant differential in brightness of values).

Green = Detail

The Blue Channel from the first image. 256 possible shades of Blue.

Typically where you will find film grain, noise, etc.

Blue = Noise and Grain