113 research outputs found

    Temperature correction of radiometric and geometric models for an uncooled CCD camera in the near infrared

    Get PDF
    International audienceThis paper presents radiometric and geometric models for both temperature and displacement noncontact measurements using an uncooled charge-coupled device (CCD) video camera. Such techniques (''one sensor-two measures'') represent an interest in many industrial low cost applications and scientific domains. To benefit from both measurements, we have to use the camera's spectral response in the near infrared spectral band from 0.75 to 1.1 mum. In this spectral band, the temperature variations of an uncooled CCD camera are taken into account in the radiometric and geometric models. By using physical models for CCD camera, we quantify detector's quantum efficiency, sensor noise and spatial resolution as a function of the wavelength and of the detector temperature. These models are confirmed by experimental results of calibration with a low cost uncooled camera based on a Sony detector and operating over the detector temperature range of -30 to -50degrees

    Multi-wavelength infrared imaging computer systems and applications

    Get PDF
    This dissertation presents the development of three computer systems for multi-wavelength thermal imaging. Two computer systems were developed for the multi-wavelength imaging pyrometers (M-WIPs) that yield non-contact temperature measurements by remotely sensing the surface of objects with unknown wavelength-dependent emissivity. These M-WIP computer systems represent the state-of-art development in remote temperature measurement system based on the multi-wavelength approach. The dissertation research includes M-WIP computer system integration, software development, performance evaluation, and also applications in monitoring and control of temperature distribution of silicon wafers in a rapid thermal process system. The two M-WIPs are capable of data acquisition, signal processing, system calibration, radiometric measurement, parallel processing and process control. Temperature measurement experiments demonstrated the accuracy of ±1°C against blackbody and ±4°C for colorbody objects. Various algorithms were developed and implemented, including real-time two-point non-uniformity correction, thermal image pseudocoloring, PC to SUN workstation data transfer, automatic IR camera integration time control, and radiometric measurement parallel processing. A third computer system was developed for the demonstration of a 3-color InGaAs FPA which can provide images with information in three different IR wavelength range simultaneously. Numbers of functions were developed to demonstrate and characterize 3-color FPAs, and the system was delivered to be used by the 3-color FPA manufacturer

    Lunar Crater Observation and Sensing Satellite (LCROSS) Instrument Calibration Summary

    Get PDF
    This document describes the calibration of the LCROSS instruments. It will be released to the public via the Planetary Data System. We need a quick review, if possible, because the data has been delivered to the PDS, and this document is needed to interpret the LCROSS impact data fully. [My mistake [shirley) in not realizing this needed to be treated as a normal publication.] The LCROSS instruments are commercially available units except for one designed and built at Ames. The commercially available instruments don't seem to me to present ITAR issues (Sony video camera, thermal camera from England, and so on.) Also, the internal design details of the instruments are not included in this report, only the process of calibrating them against standard targets. Only very high-level descriptions of the spacecraft are included, comparable to the level of detail included in the public web pages on nasa.gov

    Reverse Engineering tools: development and experimentation of innovative methods for physical and geometrical data integration and post-processing

    Get PDF
    In recent years, the use of Reverse Engineering systems has got a considerable interest for a wide number of applications. Therefore, many research activities are focused on accuracy and precision of the acquired data and post processing phase improvements. In this context, this PhD Thesis deals with the definition of two novel methods for data post processing and data fusion between physical and geometrical information. In particular a technique has been defined for error definition in 3D points’ coordinates acquired by an optical triangulation laser scanner, with the aim to identify adequate correction arrays to apply under different acquisition parameters and operative conditions. Systematic error in data acquired is thus compensated, in order to increase accuracy value. Moreover, the definition of a 3D thermogram is examined. Object geometrical information and its thermal properties, coming from a thermographic inspection, are combined in order to have a temperature value for each recognizable point. Data acquired by an optical triangulation laser scanner are also used to normalize temperature values and make thermal data independent from thermal-camera point of view.L’impiego di tecniche di Ingegneria Inversa si è ampiamente diffuso e consolidato negli ultimi anni, tanto che questi sistemi sono comunemente impiegati in numerose applicazioni. Pertanto, numerose attività di ricerca sono volte all’analisi del dato acquisito in termini di accuratezza e precisione ed alla definizione di tecniche innovative per il post processing. In questo panorama, l’attività di ricerca presentata in questa tesi di dottorato è rivolta alla definizione di due metodologie, l’una finalizzata a facilitare le operazioni di elaborazione del dato e l’altra a permettere un agevole data fusion tra informazioni fisiche e geometriche di uno stesso oggetto. In particolare, il primo approccio prevede l’individuazione della componente di errore nelle coordinate di punti acquisiti mediate un sistema di scansione a triangolazione ottica. Un’opportuna matrice di correzione della componente sistematica è stata individuata, a seconda delle condizioni operative e dei parametri di acquisizione del sistema. Pertanto, si è raggiunto un miglioramento delle performance del sistema in termini di incremento dell’accuratezza del dato acquisito. Il secondo tema di ricerca affrontato in questa tesi consiste nell’integrazione tra il dato geometrico proveniente da una scansione 3D e le informazioni sulla temperatura rilevata mediante un’indagine termografica. Si è così ottenuto un termogramma in 3D registrando opportunamente su ogni punto acquisito il relativo valore di temperatura. L’informazione geometrica, proveniente dalla scansione laser, è stata inoltre utilizzata per normalizzare il termogramma, rendendolo indipendente dal punto di vista della presa termografica

    Reverse Engineering tools: development and experimentation of innovative methods for physical and geometrical data integration and post-processing

    Get PDF
    In recent years, the use of Reverse Engineering systems has got a considerable interest for a wide number of applications. Therefore, many research activities are focused on accuracy and precision of the acquired data and post processing phase improvements. In this context, this PhD Thesis deals with the definition of two novel methods for data post processing and data fusion between physical and geometrical information. In particular a technique has been defined for error definition in 3D points’ coordinates acquired by an optical triangulation laser scanner, with the aim to identify adequate correction arrays to apply under different acquisition parameters and operative conditions. Systematic error in data acquired is thus compensated, in order to increase accuracy value. Moreover, the definition of a 3D thermogram is examined. Object geometrical information and its thermal properties, coming from a thermographic inspection, are combined in order to have a temperature value for each recognizable point. Data acquired by an optical triangulation laser scanner are also used to normalize temperature values and make thermal data independent from thermal-camera point of view.L’impiego di tecniche di Ingegneria Inversa si è ampiamente diffuso e consolidato negli ultimi anni, tanto che questi sistemi sono comunemente impiegati in numerose applicazioni. Pertanto, numerose attività di ricerca sono volte all’analisi del dato acquisito in termini di accuratezza e precisione ed alla definizione di tecniche innovative per il post processing. In questo panorama, l’attività di ricerca presentata in questa tesi di dottorato è rivolta alla definizione di due metodologie, l’una finalizzata a facilitare le operazioni di elaborazione del dato e l’altra a permettere un agevole data fusion tra informazioni fisiche e geometriche di uno stesso oggetto. In particolare, il primo approccio prevede l’individuazione della componente di errore nelle coordinate di punti acquisiti mediate un sistema di scansione a triangolazione ottica. Un’opportuna matrice di correzione della componente sistematica è stata individuata, a seconda delle condizioni operative e dei parametri di acquisizione del sistema. Pertanto, si è raggiunto un miglioramento delle performance del sistema in termini di incremento dell’accuratezza del dato acquisito. Il secondo tema di ricerca affrontato in questa tesi consiste nell’integrazione tra il dato geometrico proveniente da una scansione 3D e le informazioni sulla temperatura rilevata mediante un’indagine termografica. Si è così ottenuto un termogramma in 3D registrando opportunamente su ogni punto acquisito il relativo valore di temperatura. L’informazione geometrica, proveniente dalla scansione laser, è stata inoltre utilizzata per normalizzare il termogramma, rendendolo indipendente dal punto di vista della presa termografica

    Spaceborne sensors (1983-2000 AD): A forecast of technology

    Get PDF
    A technical review and forecast of space technology as it applies to spaceborne sensors for future NASA missions is presented. A format for categorization of sensor systems covering the entire electromagnetic spectrum, including particles and fields is developed. Major generic sensor systems are related to their subsystems, components, and to basic research and development. General supporting technologies such as cryogenics, optical design, and data processing electronics are addressed where appropriate. The dependence of many classes of instruments on common components, basic R&D and support technologies is also illustrated. A forecast of important system designs and instrument and component performance parameters is provided for the 1983-2000 AD time frame. Some insight into the scientific and applications capabilities and goals of the sensor systems is also given

    A concept for a regional coastal zone mission

    Get PDF
    thesi
    • …
    corecore