Phredlike Score Characteristics
 Estimates a probability of error for each basecall, as a function of certain parameters computed from the trace data.
 These error probabilities are to validate basecalls – increase the confidence to discriminate correct basecalls from incorrect ones

The quality value q assigned to a basecall: q = 10 × log10(p) where p is the estimated error probability for that basecall.
Parameter 1: Peak Spacing
 The ratio of the largest peaktopeak spacing, in a window of seven peaks centered on the current one, to the smallest peaktopeak spacing. The minimum possible value of one corresponds to evenly spaced peaks.
Parameter 2: Uncalled/Called Ratio 7
 The ratio of the amplitude of the largest uncalled peak, in a window of seven peaks around the current one, to the smallest called peak.
Parameter 3: Uncalled/Called Ratio 3
 Same as parameter 2, but using a window of three peaks.
Parameter 4: Peak Resolution
 The number of bases between the current base and the nearest unresolved base, times 1 (to force the parameter to have the right direction).
The Lookup Table
 There is a lookup table consisting of a set of lines, each line containing a set of parameter thresholds, together with the quality value (score) corresponding to those thresholds.
Set the Phredlike Score
 Search the lookup table, to find the lines where each corresponding parameter is bigger than the base’s, then select the highest score in the lines.