Page 52 - DCAP303_MULTIMEDIA_SYSTEMS

Multimedia Systems

notes figure 4.4: 24 Bit rGB

This idea of RGB colour space is a fundamental concept in computer graphics. In RGB space any
colour is represented as a point inside a colour cube with orthogonal axes R, G, B (See Figure
4.5).
figure 4.5: rGB Colour space

Note that grey values form a straight line from black to white along the diagonal of the cube,
r = g = b.
8 bit indexed colour

Indexed colour (See Figure 4.6) is a more economical way of storing colour bitmaps without
using 3 bytes per pixel. As with 8 bit grey bitmaps, each pixel has one byte associated with it
only now the value in that byte is no longer a colour value but an index into a table of colours,
called a palette or colour table.

figure 4.6: 8 Bit indexed Colour

46 LoveLy professionaL University