An interactive photogrammetric method for assessing deer antler quality using a parametric Computer-Aided Design system (Interactive Photogrammetric Measure Method)

Abstract

In the area of deer antler evaluation for trophy homologation, as well as in the obtaining of biometric databases for later analysis in the field of Geometric Morphometrics, different linear biometric tools have traditionally been used. In this study we used two sets of antlers from 29 Iberian red deer (Cervus elaphus hispanicus) to develop and establish a new photogrammetric technique which creates the 3D model of the antler using a parametric 3D Computer-Aided Design (CAD). This simple and reliable method for deer hunting trophy homologation was compared with the other two more extensively used methods of antler measurement, the traditional measuring tape and the Articulated Arm Coordinate Measuring Machine (AACMM or CMA). The advantage of this innovative photogrammetric method is the use of only two photographs to obtain both the 3D model and the dimensions required for antler evaluation. A procedure was performed to compare lengths and antler evaluation as hunting trophy. The three methods showed similar reliability, although the photogrammetric process using the 3D CAD system was much faster and more functional than both the traditional measuring tape and Articulated Arm methods. Since this method only requires two photographs per individual, it makes possible the study of a high percentage of antlers in the field. This new photogrammetric method has been successfully used in the biometrics area, but it could become a more extensively used method in this and other fields because of its ease of operation, speed and accuracy of data collection.