Comparison of Land Vehicle Target Detection Performance in Field Observation, Photosimulation and Videosimulation

Photosimulation is a widely used method for target detection experimentation. In the defence context, such experiments are often developed in order to derive measures for the effectiveness of camouflage techniques in the field. This assumes that there is a strong link between photosimulation performance and field performance. In this paper, we report on a three stage experiment exploring that link. First, a field experiment was conducted where observers performed a search and detection task seeking vehicles in a natural environment, simultaneously with image and video capture of the scene. Next, the still images were used in a photosimulation experiment, followed by a videosimulation experiment using the captured video. Analysis of the photosimulation results has shown that there is moderate linear correlation between field and photosimulation detection results (Pearson Correlation Coefficient, PCC = 0.64), but photosimulation results only moderately fit the field observation results, with a reduced chi(2) statistic of 1.996. Detectability of targets in the field was, mostly, slightly higher than in photosimulation. Analysis of the videosimulation results using videos of stationary and moving targets has also shown moderate correlation with field observation results (PCC = 0.62), but these are a better fit with the field observation results, with a reduced chi(2) statistic of 1.45. However, when considering videos of moving targets and videos of stationary targets separately, there appear to be two distinct trends, with videosimulation detection results being routinely higher for moving targets than the field observation results, while for stationary targets, the videosimulation detection results are mostly lower than the field observation, similar to the trend noted in the photosimulation results. There were too few moving target videos to confidently perform a fit, but the fit statistics for the stationary target videos becomes similar to that of the photosimulation, having a reduced chi(2) = 1.897.