Zusammenfassung der Ressource
Data Representation
- Images
- Bitmaps
- Image divided into a grid of pixels
- Each pixel set to a number of
bits, which can contain a set
number of colours
- If the pixel contains 4 bits, it can contain up
to 2^^4 number of colours (16)
- Increasing the size of the image increases the size
of the file as there are more pixels
- Increasing the resolution
(quality) also increases file
size
- The width of the
picture is needed in
pixels as well as
the number of bits
assigned to each
pixel
- Vector Images
- These images do not have
any data pixels but they
are a specific set of
instructions needed to
reproduce the picture
- Certain elements of the
picture are required to
make the instructions
- Shape
- Line thickness
- FIll
- Colour Depth
- Vector images build
their instructions in
relation to the photo's
point of origin
- As the picture is only a set of
instructions, resizing the photo does
not affect the resolution of the
picture
- Therefore file size is small
- Metadata
- Known as "data about data"
- vector images need metadata
- Number systems
- Binary
- Base 2 counting system,
where only the numbers 0 or 1
are used
- Computers read
data in binary
- Denary
- Base 10 counting system
where the numbers 0 to 9
are used
- Humans use denary to count
- Hexadecimal
- Base 16 counting system where the numbers 0 to 9 are
used, and the letters A, B, C, D, E, F are used to
represent the numbers 10, 11, 12 ,13 ,14 15
respectively
- Units of Information
- Bit
- Nybble
- Byte
- Kilobyte
- Megabyte
- Gigabyte
- Terabyte
- Petabyte
- Exabyte
- Yottabyte
- Zettabyte
- Sound
- Sound waves are analogue, so they
must be converted to digital
information for computers
- This is done by sampling
the wave and storing a
digital representation of
the sound
- Sampling frequency is how
often a sound wave is
sampled
- Increasing sample
frequency produces a
better quality of sound but
increases file size
- Sample rate determines how many
different tones can be represented
- High sample rate means more tones
can be represented