Browsing by Author "Rheenen, Arthur Dirk van"
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Detection: how many pixels are required?
Rheenen, Arthur Dirk van; Thomassen, Jan Brede (2020-09-23)In this work, we studied how detection range of a small target changes as a function of the number of defined target pixels. The intuitively simplest method to look for a target in IR images is to look for the “hottest” ... -
Identification of mixed substances using a random forest regressor to classify THz absorbance spectra
Rheenen, Arthur Dirk van; Aurdal, Lars; Nystad, Helle Emilia; Haakestad, Magnus W. (2018)We report on the development and application of a random forest regressor that not only identifies but also estimates the relative concentrations of substances (one explosive and two simulants), both in one-substance and ... -
MRTD: Man versus machine
Rheenen, Arthur Dirk van; Taule, Petter; Thomassen, Jan Brede; Madsen, Eirik Blix (2018)We present Minimum-Resolvable Temperature Difference (MRTD) curves obtained by letting an ensemble of observers judge how many of the six four-bar patterns they can “see” in a set of images taken with different bar-to-background ... -
MRTD: to NUC or not to NUC?
Rheenen, Arthur Dirk van; Thomassen, Jan Brede (2020-09-21)We applied a simple method to estimate the Minimum Resolvable Temperature Difference (MRTD) of an LWIR and an MWIR camera. A so-called Siemens star, in our case a thin, black aluminum plate framing a circle that is missing ... -
Non-destructive testing of graphene/epoxy composites using THz waves
Haakestad, Magnus W.; Johnsen, Bernt Brønmo; Dam, Anh Hoang; Mastin, Johann Roland M; Eid, Michel; Rheenen, Arthur Dirk van (2018-10-05)In earlier experiments [1] we found there was significant transmission of THz radiation through carbon-fiber enforced composites, despite that fact that the dc conductivity of the carbon fibers is expected to be good and ... -
Robust Identification of Concealed Dangerous Substances by Spectral Correlation of Terahertz Transmission Images
Rheenen, Arthur Dirk van; Haakestad, Magnus Willum (2015)Terahertz (THz) images containing spectral information in each pixel are recorded in transmission mode using a fiber-coupled time-domain spectroscopy system. The images are acquired by mounting a sample holder on an x-y ... -
Robust identification of concealed dangerous substances using THz imaging spectroscopy
Nystad, Helle Emilia; Haakestad, Magnus Willum; Rheenen, Arthur Dirk van (2015)False alarm rates must be kept sufficiently low if a method to detect and identify objects or substances is to be implemented in real life applications. This is also true when trying to detect and identify dangerous ... -
Sensitivity of input parameters to modelling of atmospheric transmission of long-wave infrared radiation at sea under warm and humid conditions
Thomassen, Jan Brede; Rheenen, Arthur Dirk van; Madsen, Eirik Blix; Pszczel, Mark; Bilton, Nicola; Pushkarov, Oleksandr (2018)A joint Australian-Norwegian eld trial (Osprey) was held in February 2018 in Darwin, Australia. The objective of this trial was to measure IR transmission properties of the atmosphere in a marine environment under warm and ... -
Three-dimensional signal decomposition of infrared image sequences and large-scale non-uniformity analysis
Thomassen, Jan Brede; Rheenen, Arthur Dirk van (2020-09-20)The three-dimensional noise model is a methodology to analyse the noise of a thermal imaging sensor, such as an infrared (IR) camera. This allows us to decompose a noisy signal into components and quantify properties such ...