Joar Martin Østby

• Nematzadeh, Mozhdeh; Häfliger, Philipp Dominik; Samadpoor Rikan, Behnam; Nøvik, Steffen & Østby, Joar Martin (2019). Low Noise Combined Optical-Chemical CMOS Sensor For Biomedical Application. The Midwest Symposium on Circuits and Systems conference proceedings. ISSN 1548-3746. 2019-August, s. 394–398. doi: 10.1109/MWSCAS.2019.8885280.
• Griffiths, Jennifer A.; Metaxas, Marinos G.; Royle, Gary J.; Venanzi, Christian; Esbrand, Colin & Cavouras, Dionisis [Vis alle 22 forfattere av denne artikkelen] (2008). Design and characterization of the I-ImaS multi-element x-ray detector system. IEEE Transactions on Nuclear Science. ISSN 0018-9499. 55(3), s. 827–832. doi: 10.1109/TNS.2008.2000477.
• Griffiths, J.A.; Metaxas, M.G.; Pani, S.; Schulerud, Helene; Esbrand, C. & Royle, G.J. [Vis alle 31 forfattere av denne artikkelen] (2008). Preliminary images from an adaptive imaging system. Physica Medica. ISSN 1120-1797. 24(2), s. 117–121. doi: 10.1016/j.ejmp.2008.01.003.
• Longo, R.; Asimidis, A.; Cavouras, D.; Esbrand, C.; Fant, A. & Gasiorek, P. [Vis alle 27 forfattere av denne artikkelen] (2007). A scanning system for intelligent imaging: I-ImaS. I Hsieh, Jiang & Flynn, Michael J. (Red.), Medical Imaging 2007: Physics of Medical Imaging. SPIE - The International Society for Optics and Photonics. ISSN 9780819466280. doi: 10.1117/12.708457. Vis sammendrag

  I-ImaS (Intelligent Imaging Sensors) is a European project aiming to produce adaptive x-ray imaging systems using Monolithic Active Pixel Sensors (MAPS) to create optimal diagnostic images. Initial systems concentrate on mammography and cephalography. The on-chip intelligence available to MAPS technology will allow real-time analysis of data during image acquisition, giving the capability to build a truly adaptive imaging system with the potential to create images with maximum diagnostic information within given dose constraints. In our system, the exposure in each image region is optimized and the beam intensity is a function not only of tissue thickness and attenuation, but also of local physical and statistical parameters found in the image itself. Using a linear array of detectors with on-chip intelligence, the system will perform an on-line analysis of the image during the scan and then will optimize the X-ray intensity in order to obtain the maximum diagnostic information from the region of interest while minimizing exposure of less important, or simply less dense, regions. This paper summarizes the testing of the sensors and their electronics carried out using synchrotron radiation, x-ray sources and optical measurements. The sensors are tiled to form a 1.5D linear array. These have been characterised and appropriate correction techniques formulated to take into account misalignments between individual sensors. Full testing of the mammography and cephalography I-ImaS prototypes is now underway and the system intelligence is constantly being upgraded through iterative testing in order to obtain the optimal algorithms and settings.  

• Fant, A.; Gasiorek, P.; Turchetta, R.; Avset, Berit Sundby; Bergamaschi, A. & Cavouras, D. [Vis alle 26 forfattere av denne artikkelen] (2007). I-IMAS: A 1.5D sensor for high-resolution scanning. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 573(1-2), s. 27–29. doi: 10.1016/j.nima.2006.10.389. Vis sammendrag

  We have developed a 1.5 D CMOS active pixel sensor to be used in conjunction with a scintillator for X-ray imaging. Within the Intelligent Imaging Sensors (I-ImaS) project, multiple sensors will be aligned to form a line-scanning system and its performance evaluated with respect to existing sensors in other digital radiography systems. Each sensor contains a 512×32 array of pixels and the electronics to convert the collected amount of charge to a digital output value. These include programmable gain amplifiers (PGAs) and analogue-to-digital converters (ADCs). The gain of the PGA can be switched between one or two, to increase the sensitivity for smaller collected charge; the ADC is a 14-bit successive approximation with a sampling rate of 1.25 MHz. The ASIC includes a programmable column fixed pattern noise mitigation circuit and a digitally controllable pixel reset mode block. Here we will describe the sensor design and the expected performance.

• Schulerud, Helene; Thielemann, Jens T; Kirkhus, Trine; Kaspersen, Kristin; Østby, Joar Martin & Metaxas, Marinos G. [Vis alle 28 forfattere av denne artikkelen] (2007). Adaptive Image Content-Based Exposure Control for Scanning Applications in Radiography. I Blanc-Talon, Jacques; Philips, Wilfried; Popescu, Dan & Scheunders, Paul (Red.), Advanced Concepts for Intelligent Vision Systems. 9th International Conference, ACIVS 2007, Delft, The Netherlands, August 28-31, 2007. Proceedings. Springer. ISSN 9783540746065. s. 543–552. doi: 10.1007/978-3-540-74607-2_49. Vis sammendrag

  I-ImaS (Intelligent Imaging Sensors) is a European project which has designed and developed a new adaptive X-ray imaging system using on-line exposure control, to create locally optimized images. The I-ImaS system allows for real-time image analysis during acquisition, thus enabling real-time exposure adjustment. This adaptive imaging system has the potential of creating images with optimal information within a given dose constraint and to acquire optimally exposed images of objects with variable density during one scan. In this paper we present the control system and results from initial tests on mammographic and encephalographic images. Furthermore, algorithms for visualization of the resulting images, consisting of unevenly exposed image regions, are developed and tested. The preliminary results show that the same image quality can be achieved at 30-70% lower dose using the I-ImaS system compared to conventional mammography systems.

• Griffiths, Jennifer A.; Metaxas, Marinos G.; Royle, Gary J.; Venanzi, Cristian; Esbrand, Colin & van der Stelt, Paul F. [Vis alle 30 forfattere av denne artikkelen] (2006). A Multi-Element Detector System for Intelligent Imaging: I-maS. I Phlips, Bernard (Red.), IEEE Nuclear Science Symposium Conference Record, San Diego Oct 29-Nov 1, 2006. IEEE. ISSN 1424405610. s. 2554–2558. doi: 10.1109/NSSMIC.2006.354430. Vis sammendrag

  I-ImaS is a European project aiming to produce new, intelligent X-ray imaging systems using novel APS sensors to create optimal diagnostic images. Initial systems concentrate on mammography and encephalography. Later development will yield systems for other types of radiography such as industrial QA and homeland security. The I-ImaS system intelligence, due to APS technology and FPGAs, allows real-time analysis of data during image acquisition, giving the capability to build a truly adaptive imaging system with the potential to create images with maximum diagnostic information within given dose constraints. A companion paper deals with the DAQ system and preliminary characterization. This paper considers the laboratory X-ray characterization of the detector elements of the I-ImaS system. The characterization of the sensors when tiled to form a strip detector will be discussed, along with the appropriate correction techniques formulated to take into account the misalignments between individual sensors within the array. Preliminary results show that the detectors have sufficient performance to be used successfully in the initial mammographic and encephalographic I-ImaS systems under construction and this paper will further discuss the testing of these systems and the iterative processes used for intelligence upgrade in order to obtain the optimal algorithms and settings.

• Vermesan, Ovidiu & Østby, Joar Martin (2000). A HIGH TEMPERATURE SIGMA DELTA MODULATOR ASIC. HiTEN. ISSN 2380-4491.

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• Hansen, Thor-Erik; Ferber, Alain Marc C; Ahmed, Niaz; Løvhaugen, Odd; Østby, Joar Martin & Bouquet, Grégory [Vis alle 9 forfattere av denne artikkelen] (2010). A Novel X-ray Detector System.
• Hansen, Thor-Erik; Ferber, Alain Marc C; Ahmed, Niaz; Løvhaugen, Odd; Østby, Joar Martin & Bouquet, Grégory [Vis alle 9 forfattere av denne artikkelen] (2010). A Novel X-ray Detector System.
• Østby, Joar Martin (2007). LPLV - Low Power Low Voltage. Vis sammendrag

  Foredrag holdt på SINTEF

• Vermesan, Ovidiu; Blystad, Lars-Cyril; Bahr, Roy; Grindvoll, Hanne & Østby, Joar Martin (2007). Design Considerations on Voltage Reference Generators for High Temperature Applications.
• Østby, Joar Martin (2006). SINTEF Front-end ASICs for radiation detection. Vis sammendrag

  An overview of  Asics designed by SINTEF for particle and X-ray detection

• Østby, Joar Martin (2006). Radiation detectors and ASICs designed by SINTEF. Vis sammendrag

  A presentation of some of SINTEF's  detectors and ASICs designed for particle and x-ray

• Østby, Joar Martin (2006). Measurements of APS pixels. Vis sammendrag

  Measurements and analysis of some pixel geometeries

• Østby, Joar Martin (2006). Rail-to-rail amplifiers. Vis sammendrag

  A differential amplifier based on a published single sided rail-to-rail amplifier

• Østby, Joar Martin (2006). APS Active Pixel Sensors on CMOS. Vis sammendrag

  Measurements and analysis of pixel geometries

• Østby, Joar Martin (2006). • A Programmable 1.5V CMOS Class-AB Operational Amplifier with Hybrid Nested Miller Compensation for 120dB Gain and 6MHz UGF, IFI 7/9-2006. Vis sammendrag

  Schematic implementation of architecture given in paper

• Østby, Joar Martin (2006). Operational Amplifiers– Definition of Operational Amplifiers. Vis sammendrag

  An overview of operational amplifier architectures

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