for the safety of low flying aircraft, it will become increasingly important that an aircraft should have the ability to detect and avoid small obstacles in the low flying environment. in recent years, using context information to assist in detecting power lines has shown great potential to better detect power lines at a remote distance. therefore, how to adequately use the context information for a better detection is a hot issue of concern. this paper proposes a novel auxiliary assisted power line detection method, in which the spatial context disparity of auxiliaries is quantitatively and uniformly evaluated for the first time. as a cognitive strategy, the spatial context disparity depends on two factors, the spatial context peakedness and the spatial context difference. with this cognitive method, objects that achieve high spatial context disparity scores are more suitable for being the auxiliaries of the power lines. experimental results show that, owing to the spatial context disparity, the proposed method can acquire proper auxiliaries with abundant context information to support the detection, so that better power line detections are achieved comparing to traditional power line detection methods. the proposed power line detection method, which can automatically choose the optimal auxiliaries, is effective and has the potential for practical use in ensuring the flight safety of unmanned air vehicles (uavs) in the low flying environment. © 2017 springer science+business media, llc