Foundations of Digital Image

05. Size

The ultimate way of defining the size of a digital image is using pixels.

PPI (Pixels Per Inch) Measures resolution of a file.

DPI (Dots Per Inch) Measures resolution of printing and monitor.

A bit is short for the term binary digit, with only two values: either 1 or 0. The two values can also be interpreted as logical values(true/false, yes/no), algebraic signs (+/−), activation states (on/off), or any other two-valued attribute. Bits are typically grouped in sets of eight, making up the data unit known as the byte.

There are many early forms of binary encoding. Two examples:

Knitting, there is a knit and purl stitch

Morse Code sends electrical signals that are on and off, or rather dots and dashes.


Data Sizes

Size                     Conversion                 Abbreviation

Bit                         1 bit                                 bit

Byte                     8 bits                                B

Kilobyte             1,024 bytes                  KB

Megabyte          1,024 kilobytes           MB

Gigabyte           1,024 megabytes        GB

Terabyte          1,024 gigabytes            TB

Petabyte            1,024 terrabytes         PB

Exabyte             1,024 petabytes          EX

Zettabyte          1,024 exabytes            ZB

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