ShipIR model validation using NATO SIMVEX experiment results

Holst²,

Ramaswamy

2015

SPIE Proceedings

http://www.davis-eng.com b JCD Publishing, 957 Carissa Lane, Oviedo, FL 32765 phone/fax: +1 407 365 5762; ABSTRACTExisting FLIR detection models such as NVThermIP and NV-IPM, from the U.S. Army Night Vision and Electronic Sensors Directorate (NVESD), use only basic inputs to describe the target and background (area of the target, average and RMS temperatures of both the target and background). The objective of this work is to try and bridge the gap between more sophisticated FLIR detection models (of the sensor) and high-fidelity signature models, such as the NATO-Standard ShipIR model. A custom API is developed to load an existing ShipIR scenario model and perform the analysis from any user-specified range, altitude, and attack angle. The analysis consists of computing the total area of the target (m 2 ), the average and RMS variation in target source temperature, and the average and RMS variation in the apparent temperature of the background. These results are then fed into the associated sensor model in NV-IPM to determine its probability of detection (versus range). Since ShipIR computes and attenuates the spectral source radiance at every pixel, the black body source and apparent temperatures are easily obtained for each point using numerical iteration (on temperature), using the spectral attenuation and path emissions from MODTRAN (already used by ShipIR to predict the apparent target and background radiance). In addition to performing the above calculations on the whole target area, a variable threshold and clustering algorithm is used to analyse whether a sub-area of the target, with a higher contrast signature but smaller size, is more likely to be detected. The methods and results from this analysis should provide the basis for a more formal interface between the two models.

Section: Introduction (Shipir)mentioning

confidence: 99%

Probability of detection using ShipIR/NVIPM

Holst²,

Ramaswamy

2015

SPIE Proceedings

“…The scenario model is used to monitor and manage the user inputs and commands, and update the necessary model components to refresh the display (IR scene). Validation of ShipIR has been the topic of several research papers (Vaitekunas and Fraedrich 1999, Fraedrich et al 2003, Vaitekunas 2005. A sample comparison between a FLIR mid-wave camera measurement and its ShipIR equivalent are presented in Figure 2.…”

Section: Introductionmentioning

confidence: 99%

An adaptive tracker for ShipIR/NTCS

Ramaswamy

2015

SPIE Proceedings

A key component in any image-based tracking system is the adaptive tracking algorithm used to segment the image into potential targets, rank-and-select the best candidate target, and the gating of the selected target to further improve tracker performance. This paper will describe a new adaptive tracker algorithm added to the naval threat countermeasure simulator (NTCS) of the NATO-standard ship signature model (ShipIR). The new adaptive tracking algorithm is an optional feature used with any of the existing internal NTCS or user-defined seeker algorithms (e.g., binary centroid, intensity centroid, and threshold intensity centroid). The algorithm segments the detected pixels into clusters, and the smallest set of clusters that meet the detection criterion is obtained by using a knapsack algorithm to identify the set of clusters that should not be used. The rectangular area containing the chosen clusters defines an inner boundary, from which a weighted centroid is calculated as the aim-point. A track-gate is then positioned around the clusters, taking into account the rate of change of the bounding area and compensating for any gimbal displacement. A sequence of scenarios is used to test the new tracking algorithm on a generic unclassified DDG ShipIR model, with and without flares, and demonstrate how some of the key seeker signals are impacted by both the ship and flare intrinsic signatures.

“…ShipIR/NTCS is a comprehensive software engineering tool for predicting the thermal infrared (IR) signature and IR susceptibility of naval and air ships, whose description and validation have been the subject of numerous SPIE Proceedings ( [1], [2], [3], [4], [5], [6]). Basic sensor information, geography, and meteorology (including date and time) are input to a background model utilizing MODTRAN [7] for sun and sky radiance, and atmospheric propagation, and a proprietary model for the average and root-mean-square (RMS) variance in sea radiance.…”

Section: Introductionmentioning

confidence: 99%

Validation of ShipIR (v4.2)

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXIV

Aleksandrov

2023

Numerous improvements have been made to various sub-models in the NATO-standard and USN accredited naval ship infrared signature model (ShipIR) since its last validation in SPIE using ShipIR (v3.2). These include upgrades to MODTRAN5 and MODTRAN6 for the sun, sky, and atmosphere models, and various fixes and improvements to the sea model: corrections to the Fresnel sea reflectance formula (v3.3a), empirical 2nd-order hiding (v3.4), and a recent fix to the sea surface roughness slope distribution (v4.2). This paper will revisit the previous experimental results, used to validate ShipIR (v3.2), first comparing these results against the steady-state version of the thermal solver in ShipIR (v4.2) and complementing these with the transient thermal solver introduced in ShipIR (v4.0).