Digital stereovision system for dendrometry, georeferencing and data management

A stereovision system for the in-field estimation of trees parameters such as height anddiameter is proposed. The system includes a specifically developed mobile application forthe management and georeferencing of stereo images. Stereo imaging allows the measurementof the distance between two points using triangulation formulas for theextraction of three-dimensional coordinates. The methodology is structured following three phases: training using system calibration through stereovision analysis of knownartificial known objects; testing using measurements of standing tree diameters andheights acquired through stereovision system, laser rangefinder (height) and tree calliper (diameter); field application testing using direct height and diameter measurements innatural and urban woods. For this last phase an Android application was developed. Theresults show that the error between direct measurements and those measured with bothstereovision and traditional reference methods (laser rangefinder and tree calliper) were quite low: 6.8 ± 6.6% between direct and laser rangefinder height measurements; 5.8 ± 5.5% between direct and stereovision height measurements; 4.2 ± 3.0% between direct andstereovision diameter measurements. No significant difference was found between thedifferent methods for estimating height and diameter. Around 200 images matched to stereovision acquisitions were acquired and georeferenced using the application.