Exact ray-tracing computation of narcissus-equivalent temperature difference in scanning thermal imagers

1992 ◽  
Author(s):  
Juan L. Rayces ◽  
Lan Lebich
Keyword(s):  
Ray Tracing ◽  
Temperature Difference ◽  
Equivalent Temperature ◽  
Thermal Imagers

scholarly journals A Study of Noise Equivalent Temperature Difference of Thermograph.

2000 ◽  
Vol 66 (643) ◽  
pp. 824-829
Author(s):  
Katashi KUROKAWA ◽  
Masahiro AGU ◽  
Terumi INAGAKI ◽  
Yoshizo OKAMOTO
Keyword(s):  
Temperature Difference ◽  
Equivalent Temperature ◽  
Noise Equivalent Temperature Difference

Development of Double-cantilever Infrared Focal Plane Arrays: Fabrication and Post-process Curvature Modification

2006 ◽  
Vol 952 ◽  
Author(s):  
Shusen Huang ◽  
I-Kuan Lin ◽  
Hu Tao ◽  
Xin Zhang
Keyword(s):  
Temperature Difference ◽  
Infrared Radiation ◽  
Focal Plane ◽  
Recent Progress ◽  
Focal Plane Arrays ◽  
Equivalent Temperature ◽  
Theoretical Limit ◽  
Infrared Focal Plane Arrays ◽  
Post Process ◽  
Noise Equivalent Temperature Difference

ABSTRACTUncooled double-cantilever microbolometers have the potential of reaching a noise-equivalent temperature difference (NETD) approaching the theoretical limit and thus have gained increasing interest. Each pixel of the device consists of two overlapping bimaterial cantilevers that deflect in opposite directions as their temperature rises due to the absorption of incident infrared radiation. This paper reports recent progress in the development of these double-cantilever focal plane arrays (FPAs), including fabrication and post-process curvature modification.

scholarly journals A SIMPLIFIED APPROACH FOR PREDICTING EARLY-AGE CONCRETE PAVEMENT DEFORMATION / SUPAPRASTINTAS METODAS, PROGNOZUOJANTIS ANKSTYVOJO BETONO DANGOS DEFORMACIJAS

2011 ◽  
Vol 17 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Sunghwan Kim ◽  
Kasthurirangan Gopalakrishnan ◽  
Halil Ceylan
Keyword(s):  
Environmental Factors ◽  
Temperature Difference ◽  
Primary Response ◽  
Complex Nature ◽  
Early Age ◽  
Deformation Characteristics ◽  
Equivalent Temperature ◽  
Linear Temperature ◽  
Simplified Approach ◽  
Deformation Properties

Studies on deformation characteristics of early-age Jointed Plain Concrete Pavements (JPCP) due to environmental effects have drawn significant interest over the years. However, the complex nature of the problem arising from interacting environmental factors has resulted in difficulties in predicting the JPCP deformation characteristics. This study introduces a simplified approach for predicting the early-age deformation of JPCP due to environmental factors using an equivalent temperature difference concept. A newly constructed JPCP section on highway US–30 near Marshalltown, Iowa was instrumented to monitor the pavement response to variations in temperature and moisture during the first seven days after construction. Based on the collected field data, the total equivalent linear temperature difference (ΔTteltd ) corresponding to the actual deformation was quantified using Finite Element (FE) based approach, namely ISLAB 2000. The FE-based calculations were compared with the field measured slab deformation properties. Better predictions were obtained when employing a simplified equivalent temperature difference (ΔTteltd) concept for FE based primary response model. Santrauka Pastaraisiais metais ypač domimasi ankstyvojo betono kelio dangos (JPCP) deformacijos charakteristikomis ir poveikio aplinkai tyrimais, tačiau dėl aplinkos veiksnių sąveikos kyla sunkumų prognozuojant JPCP būdingąsias deformacines savybes. Šiame darbe pateikiamas supaprastintas metodas, kaip galima būtų prognozuoti ankstyvojo betono deformacijas JPCP, kylančias dėl aplinkos veiksnių, vartojant ekvivalentinės temperatūros skirtumo sąvoką. Naujai statomame JPCP US-30 plente prie Maršaltauno Ajovoje buvo sukonstruota bandymų įranga ir stebėta dangų reakcija į temperatūros bei drėgmės pokyčius per pirmąsias septynias dienas po statybų pabaigos. Remiantis gautais rezultatais, visų lygiaverčio linijinės temperatūros skirtumų (ΔTteltd ), atitinkančių faktinę deformaciją, vertės buvo skaičiuojamos taikant baigtinių elementų (FE) metodą su ISLAB 2000. Apskaičiuotos FE vertės buvo palygintos su natūrinėmis sąlygomis išmatuotomis deformacinėmis savybėmis. Tikslesnė prognozė buvo gauta taikant supaprastintą temperatūrų skirtumo (ΔTteltd ) metodiką, grindžiamą pirminiu FE modeliu.

scholarly journals Virtual MRTD – an indirect method to measure MRTD of thermal imagers using computer simulation

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Krzysztof Chrzanowski ◽  
Nguyen Hong Viet
Keyword(s):  
Computer Simulation ◽  
Temperature Difference ◽  
Measurement Method ◽  
Indirect Method ◽  
Lower Cost ◽  
Human Observer ◽  
Thermal Imager ◽  
Spatial Frequencies ◽  
Thermal Imagers ◽  
Measurement Concept

Minimum resolvable temperature difference (MRTD) is considered as the most important parameter of thermal imagers. A new method of MRTD measurement without drawbacks of other methods is presented in this paper. Proposed MRTD measurement method coded as virtual MRTD is based on a three steps measurement concept using semi-automatic objective measurements and computer simulation. First, objective parameters of the tested thermal imager are measured. Second, software simulates this tested thermal imager and generates the image of 4-bar target of specified spatial frequency (size) and contrast (temperature difference). Third, a human observer analyses the images of the 4-bar target generated by the software on the screen of PC set and measures MRTD of the simulated thermal imager at specified set of spatial frequencies. The proposed method offers higher measurement speed, lower cost and typically better accuracy in comparison with the typical MRTD measurement method.

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