TOD Performance Theoretical Model for Staring Thermal Imagers
Source: International Journal of Infrared and Millimeter Waves, Volume 25, Number 11, November 2004 , pp. 1645-1656(12)
Abstract:The TOD (triangle orientation discrimination threshold) metric, as a promising sensor performance measure, is suitable for all types of thermal imaging systems and corresponds to the field performance very well. Since this method was proposed, a great progress has been made in some aspects, such as experimental validation, field performance, and TOD sensor performance model. However, what is still missing is a TOD curve prediction model similar to MRTD (minimum resolvable temperature difference) equation. Here, an equation‐based TOD performance model was first developed focusing on staring thermal imagers. Specifically, spatial distribution of the triangle standard test pattern is described quantitatively. Resolution transfer characteristic of the staring infrared imagers is modeled with linear system theory, and system noise is characterized with the introduction of three‐dimensional noise model. The modulation effect of overall subsystem of staring thermal imager on the non‐periodic triangle standard pattern is analyzed. The matched filter idea is adopted to characterize quantitatively the spatial integration of the eye to signal and various noise components over the triangle pattern area, and the perceived signal‐to‐noise ratio of the staring thermal imager is derived. Then, the TOD performance theoretical model is established. Comparing with experimental results, this theoretical model gives reasonable prediction of the TOD performance curve of staring thermal imagers. Although more tests and modifications are required, these preliminary results suggest that this model can be developed into a model that predicts the TOD for all kinds of sensors.
Document Type: Research Article
Affiliations: 1: School of Technical Physics, Xidian University, Xi'an shaanxi 710071, People's Republic of China; Xi'an Institute of Applied Optics, Xi'an shaanxi 710065, People's Republic of China 2: School of Technical Physics, Xidian University, Xi'an shaanxi 710071, People's Republic of China 3: Xi'an Institute of Applied Optics, Xi'an shaanxi 710065, People's Republic of China
Publication date: November 1, 2004