Figure 8

Improvement of base-calling by using Partitioning and Re-sampling (PnR) technique. For an observed base (shaded boxes), VarDetect divides a chromatogram peak into four equal parts (partitions) and focuses at the two middle parts (a). The two vectors $\overrightarrow{u}$ and $\overrightarrow{v}$ are created by connecting the points that the curve segment of the secondary peak crosses over the two partitions (b). Let $\overrightarrow{u}$^⊥ be a perpendicular vector of $\overrightarrow{u}$ by rotating it 90 counter-clockwise (c). Then the secondary peak curve has a turning point if the dot product of $\overrightarrow{u}$^⊥·$\overrightarrow{v}$ produces a negative value. In other words, if the angle θ between $\overrightarrow{v}$ and $\overrightarrow{u}$^⊥ is obtuse, this secondary peak could be interpreted as being heterozygous peak (d).