PhredQuality
objects store characters that are interpreted as
[0 - 99] quality measures by subtracting 33 from their ASCII decimal
representation (e.g. ! = 0, " = 1, \# = 2, ...). Quality measures q
encode probabilities as -10 * log10(p)
.
SolexaQuality
objects store characters that are interpreted as
[-5 - 99] quality measures by subtracting 64 from their ASCII decimal
representation (e.g. ; = -5, < = -4, = = -3, ...). Quality measures q
encode probabilities as -10 * (log10(p) - log10(1 - p))
.
IlluminaQuality
objects store characters that are interpreted
as [0 - 99] quality measures by subtracting 64 from their ASCII
decimal representation (e.g. @ = 0, A = 1, B = 2, ...). Quality
measures q encode probabilities as -10 * log10(p)