Table 1. Original and refined histograms bin sizes and selected threshold values of them by thresholding methods, and IoU criteria values are shown.

Methods Median Otsu
Test images\Types of histogram Original Refined Original Refined
Image 1DIBCO2019 track A Bin number 256 24,330 256 24,330
Threshold T= 112 12,165 188 14,966
IoU 0.94 0.92 0.91 0.88
Image 2DIBCO2019 track A Bin number 256 26,658 256 26,658
Threshold T= 123 13,329 113 15,393
IoU 0.23 0.96 0.97 0.94
Image 3Brodatz(#D34) Bin number 256 5,792 256 5,792
Threshold T= 122 2,896 104 1,972
IoU 0.23 0.68 0.29 0.87
Image 4Brodatz(#D42) Bin number 256 15,192 256 15,192
Threshold T= 118 7,596 131 6,449
IoU 0.49 0.58 0.49 0.66
Image 5 Bin number 256 6,583 256 6,583
Threshold T= 111 3,291 68 2,276
IoU 0.26 0.51 0.64 0.75
Image 6 Bin number 256 12,193 256 12,193
Threshold T= 128 6,096 97 4,958
IoU 0.67 0.83 0.93 0.94