| function FINDCENTER (image_height, image_width, image, threshold, row, column) return identifies the centroid |
| coordinates of a PL region |
| 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 |
| row, row coordinate of known pixel belonging to PL blob |
| column, column coordinate of known pixel belonging to PL blob |
| |
| minCol ← column |
| maxCol ← column |
| While maxCol < image_width AND image[row][maxCol] ≥ threshold |
| maxCol ← maxCol + 1 |
| minCol ≥ 0 AND image[row][minCol] ≥ threshold |
| minCol ← minCol − 1 |
| distanceCol ← maxCol – minCol |
| centerCol ← minCol + distanceCol/2 |
| minRow ← row |
| maxRow ← row |
| while maxRow < image_height AND image[maxRow][centerCol] ≥ threshold do |
| maxRow ← maxRow + 1 |
| while minRow ≥ 0 AND image[minRow][centerCol] ≥ threshold do |
| minRow ← minRow – 1 |
| distanceRow ← maxCol – minCol |
| centerRow ← minCol + distanceRow/2 |
| return (centerRow, centerCol) |
