The (H) under bar igh-(D) under bar efinition (I) under bar nfra-(R) under bar ed (HDIR) thermal-imaging system is a thermal camera with highest geometrical resolution producing a video signal according to the HDTV ((H) under bar igh-(D) under bar efinition (T) under bar ele-(V) under bar ision) standard. The thermal-imaging system is a parallel-scanning device with twofold interlace. Its detector is sensitive within the 7...11 mum spectral region and features 576 x n elements (n being the number of TDI stages). It has been carefully optimised in terms of range performance and size of optical entrance pupil as well as feasibility of production and yield. The 16:9 aspect ratio of the HDTV standard together with the high number of 1920 pixels/line and 1152 lines propose a drastic increase in range performance. In fact, model calculations predict an increase of up to 60 % for identification range as compared to present-standard TV-compatible thermal imagers with the same vertical field of view. With the HDIR having been integrated into a German main battle tank Leopard 2, trials were undertaken in comparison with other equipment like the OPHELIOS and the Common Module WBG-X.