A standardized 8-cm x 8-cm, L-shaped reference scale developed by the American Board of Forensic Odontology (ABFO). Inclusion of three circles across the scale allows for identification and compensation for image distortion resulting from an oblique camera angle. Measurements can be calculated using the 1-cm and 1-mm imprinted gridlines. These gridlines allow for compensation of distortion resulting from non-parallelism between the planes of the camera lens/sensor and the object being photographed. The alternating 1-cm black and white grids are useful for approximating measurement from high-light/low-light images.

Synonyms: ABFO ruler, ABFO #2, ABFO scale