Zusammenfassung der Ressource
Fundamentals of Data Representation
- Representing images
- Pixel: Picture Element;
a single point in a
graphical image
- VDUs display pictures by dividing
the dispaly screen into thousands
of pixels, arranged into rows and columns
- Bitmaps
- image resolution =
width x hight
- Colour depth
- Number of bits used to
represent each pixel
- File size= width
x height x
colour depth
- Representing Sound
- sound is analogue
- must be converted to a
digital form for storage and
processing in a computer
- Sampling
- Sample: measure
of amplitude at a
point in time
- Sound waves are
sampled to create the
digital version of sound
- Digital
representation of
sound
- sampling rate
- number of samples taken in a
second - measured in hertz
- Sample resolution
- the number of
bits per sample
- Sound File
- rate x resolution
x seconds
- Data Compression
- used to reduce file sizes
- Lossless compressioon
- reduces the size of a file
without any damage to the
file or reduction in quality
- Examples
- Huffman coding
- Run length encoding
- Lossy compression
- permanently removes data from
the file that the computer believes
you can do without
- Examples
- MP3, MP4 and JPG