RGB = HEX2RGB(HEX) converts the hexadimal color string HEX to its corresponding RGB values. RGB has three columns representing the red, green and blue component of the colour.
For a cell array of color strings, RGB will have as many rows as elements of the cell array. For a character array HEX, RGB will have as many rows as HEX.

Three-digit hexadecimal color strings are expanded to six-digit strings by doubling each digit (i.e., XYZ -> XXYYZZ).

Examples:
hex2rgb('556b2f') % 6 digit string
% -> [ 85 107 47]
hex2rgb('f0f') % 3 digit string
% -> [255 0 255]
hex2rgb({'8B4513','FF0'}) % cell array
% -> [139 69 19 ; 255 255 0]
hex2rgb(['FF6347' ; '40E0D0']) % character array with multiple rows
% -> [255 99 71 ; 64 224 208]

Hexadecimal color strings are three-byte triplets representing the red, green and blue component. One byte represents a number in the range 00 to FF (in hexadecimal notation).
More information:
http://en.wikipedia.org/wiki/Web_colors