document

Colorizing single band intensified nightvision images

Toet, A. (author), TNO Defensie en Veiligheid (author)

We present a method to give single band intensified nightvision imagery a natural day-time color appearance. For input, the method requires a true color RGB source image and a grayscale nightvision target image. The source and target image are both transformed into a perceptually decorrelated color space. In this color space a best matching...

article 2005

document

The modelling of high-rise buildings' influences for application in a semi-deterministic propagation model

Nikkelen, S.A.G. (author), Nikookar, H. (author), Mantel, O.C. (author), TNO Informatie- en Communicatietechnologie (author)

In this paper a newly applied approach to model the effects of high-rise blocking buildings near a base station (BS) in cellular communications networks is presented. Although recently accurate deterministic propagation prediction methods have become popular to account for these propagation effects, many mobile operators still employ rather...

conference paper 2005

document

Net analyte signal based statistical quality control

Skibsted, E.T.S. (author), Boelens, H.F.M. (author), Westerhuis, J.A. (author), Smilde, A.K. (author), Broad, N.W. (author), Rees, D.R. (author), Witte, D.T. (author), TNO Kwaliteit van Leven (author)

Net analyte signal statistical quality control (NAS-SQC) is a new methodology to perform multivariate product quality monitoring based on the net analyte signal approach. The main advantage of NAS-SQC is that the systematic variation in the product due to the analyte (or property) of interest is separated from the remaining systematic variation...

article 2005

document

A language modeling approach to the Text Retrieval Conference

TNO Informatie- en Communicatietechnologie (author), Hiemstra, D. (author), Kraaij, W. (author)

In this paper we present the language modeling approach to information retrieval as a toolbox to systematically combine information from different sources. Four TREC subtasks (Ad Hoc, Entry Page, Adaptive Filtering and Cross-language) are used to illustrate the application of language models to different information retrieval problems.

bookPart 2005

document

Influence of surface roughness on space charge limited emission

Nijkerk, M.D. (author), Kruit, P. (author)

Computations of space charge limited currents from thermionic emitters often rely on simple one-dimensional analytical models. The geometric limitations of these models are circumvented by applying the models locally over the emitter surface. The validity of the analytical models is compromised by the presence of surface roughness that...

article 2004

document

Characteristics of peaks of inhalation exposure to organic solvents

Preller, L. (author), Burstyn, I. (author), de Pater, N. (author), Kromhout, H. (author), TNO Voeding (author)

Objectives: To determine which exposure metrics are sufficient to characterize 'peak' inhalation exposure to organic solvents (OS) during spraying operations. Methods: Personal exposure measurements (n = 27; duration 5-159 min) were collected during application of paints, primers, resins and glues in 15 companies. A MiniRAE Photolonization...

article 2004

document

Variability of Task-based Dermal Exposure Measurements from a Variety of Workplaces

Kromhout, H. (author), Fransman, W. (author), Vermeulen, R. (author), Roff, M. (author), van Hemmen, J.J. (author), TNO Voeding (author)

Introduction: The RISKOFDERM project collected task-based estimates of potential dermal exposure from a wide range of industries and services from around Europe. A formal statistical analysis was carried out to explore the main components of variability in dermal exposure levels. The central research question was to what extent dermal exposure...

article 2004

document

Absorption of the eye lens and macular pigment derived from the reflectance of cone photoreceptors

Zagers, N.P.A. (author), van Norren, D. (author)

We measured the amplitude of the directional component of the bleached fundus reflectance, the so-called optical Stiles-Crawford effect, as a function of wavelength. The directional reflectance originates from within the outer segments of the photoreceptors. Thus only two anterior absorbers are of importance: Macular pigment and the crystalline...

article 2004

document

Transferring color to single band intensified nightvision images

Toet, A. (author)

We present a method to give single band intensified nightvision imagery a natural day-time color appearance. For input, the method requires a true color RGB source image and a grayscale nightvision target image. The source and target image are both transformed into a perceptually decorrelated color space. In this color space a best matching...

conference paper 2004

document

The Effect of Gamma and Chroma on the Perception of Color Images

Dijk, J. (author), Verbeek, P.W. (author), Walraven, J. (author), Young, I.T. (author)

We present the results of experiments in which we manipulated color images in the CIELAB space by first applying a scaling factor on chroma (C*). After this we applied a gamma transformation (an exponent relating the input to the output) to the luminance (Y) in XYZ space, while keeping the chromaticity values (x, y) constant. The aim of the...

conference paper 2002

document

De Vries-Weber gain control and dark adaptation in human vision

Bouman, M.A. (author)

Thresholds for seeing light from a stimulus are determined by a mechanism that pairs subliminal excitations from both halves of a twin unit. Such excitations stem from a package of k ≥ 1 receptor responses. A half-unit contains one red or one green cone and P rods. The receptor's "Weber machine" controls the receptor's gain. Each half of a twin...

article 2002

document

The importance of prior probabilities for entry page search

Technisch Physische Dienst TNO - TH (author), Kraaij, W. (author), Westerveld, T. (author), Hiemstra, D. (author)

An important class of searches on the world-wide-web has the goal to find an entry page (homepage) of an organisation. Entry page search is quite different from Ad Hoc search. Indeed a plain Ad Hoc system performs disappointingly. We explored three non-content features of web pages: page length, number of incoming links and URL form. Especially...

conference paper 2002

document

The effectiveness of monostatic and bistatic deployment of low frequency active sonar

Mountain, J.A.R. (author), Ainslie, M.A. (author), Martin, P.L.R. (author), Hughes, M.R. (author), Seto, L.Y. (author), Laker, R.A. (author), Robins, A.J. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The merits of monostatic and bistatic geometries in terms of the evasion probability for area and barrier searches were described. Detection probabilities were calculated by generating signal excess surfaces for a given sonar geometry. Acoustic modeling and operational analysis allowed to detect the impact of the problem on performance and...

article 2001

document

Guidelines for accurate TOD measurement

Bijl, Piet (author), Valeton, J. Mathieu (author), TNO Human Factors Research Institute (author)

The Triangle Orientation Discrimination (TOD) threshold is an alternative method to characterize electro-optical system performance. The method is based on an improved test pattern, a better-defined observer task and a solid psychophysical measurement procedure, and allows accurate and comparable results from different measuring teams. With the...

conference paper 1999

document

The grey areas in soil pollution risk mapping: The distinction between cases of soil pollution and increased background levels

van der Gaast, N. (author), Leenaers, H. (author), Zegwaard, J. (author), Nederlands Instituut voor Toegepaste Geowetenschappen TNO (author)

The progress of soil clean up in the Netherlands is severely hindered by the lack of common agreement on how to describe the grey areas of increased background levels of pollutants. In this study practical methods are proposed in which background levels are described as distribution functions within map units of comparable homogeneity. To...

article 1998

document

Alternative short tests for inspection and maintenance of in-use cars with respect to their emissions performance

Samaras, Z. (author), Zachariadis, T. (author), Joumard, R. (author), Vernet, I. (author), Hassel, D. (author), Weber, F.-J. (author), Rijkeboer, R.C. (author), TNO Wegtransportmiddelen (author)

This paper presents the first results of a project aimed at evaluation of a number of short tests that can be alternatively used for Inspection and Maintenance of in-use cars emissions performance. For this purpose, a large number of in-use cars from four European countries was tested according to a test protocol that included a wide selection...

article 1998

document

Trace element concentrations and stable lead isotopes in soils as tracers of lead pollution in Graft-De Rijp, the Netherlands

Walraven, N. (author), van Os, B.J.H. (author), Klaver, G.Th. (author), Baker, J.H. (author), Vriend, S.P. (author), Rijks Geologische Dienst (author)

Graft-De Rijp is a former village of whalers, situated twenty-five kilometres north of Amsterdam, the Netherlands. Since the foundation of De Rijp in 1612 a mixture of sludge, manure and town refuse (containing Pb-based household artefacts and Pb-based building materials) was used to raise and fertilise the land. Gasworks, coal storehouses,...

article 1997

document

Experimental evaluation of thermal camouflage effectiveness

TNO Fysisch en Elektronisch Laboratorium (author), Jacobs, P.A. (author)

The detectability of a target in the infrared spectral region is determined by differences between the radiative signatures of the target and the local background. This implies that both, the difference in surface temperature and emissivity ΔT resp. Δε and the distribution of these differences over the target area and the background, are of...

conference paper 1995

document

Routine multiple imputation in statistical databases

TNO Preventie en Gezondheid (author), van Buuren, S. (author), van Mulligen, E.M. (author), Brand, J.P.L. (author)

This paper deals with problems concerning missing data in statistical databases. Multiple imputation is a statistically sound technique for handling incomplete data. Two problems should be addressed before the routine application of the technique becomes feasible. First, if imputations are to be appropriate for more than one statistical analysis...

conference paper 1994