Table 2.
Detection accuracy and performance of the visual detection of pipe apparent contours.
| Contour Detection Method | Indoor Error Rate 1 | Outdoor Error Rate 2 | Avg. Rate |
|---|---|---|---|
| Canny + Hough Transform (a) | 23.45% | 48.71% | 8.64 Hz |
| a + Adaptive Binarization (b) | 17.29% | 33.56% | 2.34 Hz |
| LSD + Hough Transform (c) | 19.42% | 29.38% | 21.4 Hz |
| c + LiDAR based priors (d) | 1.32% | - 3 | 19.78 Hz |
1,2 False positive rate (i.e., a contour not pertaining to the pipe or presenting wrong fitting is found). 3 No outdoor data with LiDAR and image is available.