| function ALGORITHM (image_height, image_width, image, threshold, lookup_table, est_row, est_col) return centroid |
| coordinates of a PL, or failure |
| inputs: image_height, height of the image |
| image_width, width of the image |
| image, captured grayscale image |
| threshold, lower limit of brightness to identify pixels belonging to PL blob |
| lookup_table, predefined spiral search path relative to estimation of PL centroid in current image |
| est_row, estimated row location for PL centroid in current image |
| est_col, estimated column location for PL centroid in current image |
| |
| index ← 0 to SIZE(lookup_table) do |
| column ← est_col + lookup_table[index].x |
| row ← est_row + lookup_table[index].y |
| imagerowcolumn ≥ then |
| centroid.row, centroid.col) ← FINDCENTERimage_height, image_width, image, threshold, row, column) |
| (centroid.row, centroid.col |
| return failure/⋆didn’t found any center—will use another search algorithm for the rest of the image⋆/ |
