Acquisition of morphological data in the warm-blooded horse

This paper presents a method for the measurement of morphological features of horses that is suitable for mobile applications and requires only a smartphone camera to perform measurements with a short preparation time. This study compares, various body lengths of 46 warmblood horses. The 3D-coordinates were determined photogrammetrically i.e.), using overlapping photographs and video recordings. To measure the relevant points, 12 markers were affixed at significant points to the left body side of the horses. A local coordinate system was defined by using a mobile reference frame to ensure that the measurements can be collected independently of local conditions and still are directly comparable. The measurements were repeated three times and analyzed for their accuracy by various statistical methods. With an average standard deviation of 1.75 cm for the three repeated body length measurements, the method is very reliable. The repetitions of the body length measurements showed that body parts with a high mobility, especially the measurements from the neck to the withers, have a significant impact on the attainable accuracy. To determine the absolute accuracy of the photogrammetric measurement method, a single horse was also measured with a terrestrial laser scanner (TLS). The standard deviation of the two measurements was between 0.24 cm and 1.79 cm, which demonstrates the high absolute accuracy of the measurement method.