Figure 4.

Error detection in calcified particle identification and effect of image preprocessing. (A) SEM backscattering image 1 shows the presence of large holes that are detected by the BPL method. SBP entirely erased hole-like structures (asterisks) resulting in a large decrease in false positives. (B) SEM backscattering image 2 shows that small particles (arrow heads) are often missed by BPL. FEP enhances contrast to allow detection of these small particles but also leads to false positives from the edges of other structures in the image (short arrows). (C,D) FpPL reduced false positives (green dots) and false negatives (red dots) and increased accurate particle detection (cyan dots) in images with hole-like structures and sharp edges. (E) Detection rate (%) of each method is shown for images 1–4.