Dr. Denny L. Lee Profile

Dr. Denny L. Lee

CEO

SPIE Involvement:

Author

Publications (30)

Proceedings Article | 4 April 2022 Presentation

Energy resolution of amorphous selenium detectors: conventional vs unipolar charge sensing

Ahmet Camlica, Denny Lee, Hyunsuk Jang, M. Zahangir Kabir, Karim Karim

Proceedings Volume PC12031, PC120310G (2022) https://doi.org/10.1117/12.2613030

KEYWORDS: Sensors, Selenium, Photon counting, Electric field sensors, Spatial resolution, Time metrology, Surgery, Spectroscopy, Spectroscopes, Single photon

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Proceedings Article | 1 March 2019 Presentation + Paper

Novel direct conversion imaging detector without selenium or semiconductor conversion layer

Denny Lee, Andrew Maidment, Ali Kassaee, Lei Dong, Taoran Li, Trevor Vent, Heather Petroccia, Peyton Irmen, Irina Malajovich, Kang Heo, Dooho Kim, Hyunsuk Jang

Proceedings Volume 10948, 1094818 (2019) https://doi.org/10.1117/12.2512127

KEYWORDS: Sensors, Dielectrics, Electrodes, X-rays, Image sensors, Ionization, Selenium, Semiconductors, Electron beams, Modulation transfer functions

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Proceedings Article | 9 March 2018 Paper

A novel radiation imaging detector with proportional charge gain

Denny Lee, Hyunsuk Jang, Ahmet Camlica, Karim Karim

Proceedings Volume 10573, 105735X (2018) https://doi.org/10.1117/12.2293429

KEYWORDS: Electrodes, Sensors, Selenium, Dielectrics, Interfaces, Image sensors, Ionization, Electrons, Image processing, Digital imaging

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Proceedings Article | 17 March 2011 Paper

Low-noise thin-film transistor array for digital x-ray imaging detectors

Denny Lee

Proceedings Volume 7961, 79610R (2011) https://doi.org/10.1117/12.877900

KEYWORDS: Transistors, Capacitance, X-rays, Amplifiers, Capacitors, Switching, Sensors, X-ray imaging, Field effect transistors, Thin films

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Proceedings Article | 19 March 2010 Paper

Removal of trapped charge in selenium detectors

Denny Lee, Andrew D. Maidment

Proceedings Volume 7622, 762218 (2010) https://doi.org/10.1117/12.845279

KEYWORDS: Selenium, Sensors, X-rays, Electrodes, X-ray detectors, X-ray imaging, Signal detection, Interfaces, Phase shift keying, Medical imaging

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Proceedings Article | 30 August 2006 Paper

Stability, dark current, noise, and performance optimization of selenium detectors

Denny Lee

Proceedings Volume 6319, 63191I (2006) https://doi.org/10.1117/12.687626

KEYWORDS: Selenium, Sensors, X-rays, X-ray detectors, X-ray imaging, Medical imaging, Electrodes, Electron transport, Dielectrics, Coating

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Proceedings Article | 20 April 2005 Paper

Selenium detector with a grid for selenium charge gain

Denny Lee

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.594623

KEYWORDS: Selenium, X-rays, Sensors, Signal to noise ratio, Electrodes, X-ray imaging, Interference (communication), X-ray detectors, Medical imaging, Digital mammography

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Proceedings Article | 20 April 2005 Paper

A simple edge device method for determining the presampling modulation transfer function (MTF) of flat field digital detectors

Beilei Wang, Kenneth Barner, Denny Lee, Brian Rodricks, Chuande Liu

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.595243

KEYWORDS: Modulation transfer functions, Sensors, Image processing, Imaging systems, Digital imaging, Fourier transforms, Signal to noise ratio, Computing systems, X-rays, Optical alignment

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Proceedings Article | 26 October 2004 Paper

New developments in full-field radiography detectors: Direct conversion selenium detector with avalanche gain layer

Denny Lee, George Storti, Kelly Golden

Proceedings Volume 5541, (2004) https://doi.org/10.1117/12.565869

KEYWORDS: Selenium, Sensors, X-rays, Electrodes, Signal to noise ratio, X-ray imaging, Radiography, X-ray detectors, Digital mammography, Ionization

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Proceedings Article | 12 May 2004 Paper

Algebraic tomosynthesis reconstruction

Beilei Wang, Kenneth Barner, Denny Lee

Proceedings Volume 5370, (2004) https://doi.org/10.1117/12.534658

KEYWORDS: Reconstruction algorithms, X-rays, Image processing, Image quality, Computer simulations, 3D image processing, Sensors, Detection and tracking algorithms, Algorithm development, Radiography

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Proceedings Article | 6 May 2004 Paper

Fast reconstruction for unconstrained cone-beam tomosynthesis

Beilei Wang, Kenneth Barner, Denny Lee

Proceedings Volume 5368, (2004) https://doi.org/10.1117/12.534597

KEYWORDS: Sensors, X-ray sources, Reconstruction algorithms, X-rays, Image quality, Optical simulations, Strontium, Radiography, Image processing, Tomography

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Proceedings Article | 30 December 2003 Paper

Direct-conversion x-ray imaging detector improvements and observations

Denny Lee, Chuande Lui, Kelly Golden

Proceedings Volume 5199, (2003) https://doi.org/10.1117/12.509388

KEYWORDS: X-rays, Sensors, Selenium, Dielectrics, X-ray detectors, X-ray imaging, Image sensors, Absorption, Radiography, Electrodes

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Proceedings Article | 3 May 2002 Paper

Direct-conversion imaging panel having a charge transport layer with controlled time constant

Denny Lee, James Davis

Proceedings Volume 4682, (2002) https://doi.org/10.1117/12.465615

KEYWORDS: Selenium, Dielectrics, Capacitors, Electrodes, Capacitance, Field effect transistors, X-rays, Medical imaging, Thin films, Transistors

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Proceedings Article | 3 May 2002 Paper

Characterization of a full-field digital mammography detector based on direct x-ray conversion in selenium

Jeffrey Yorker, Lothar Jeromin, Denny Lee, Eugene Palecki, Kelly Golden, Zhenxue Jing

Proceedings Volume 4682, (2002) https://doi.org/10.1117/12.465568

KEYWORDS: Sensors, Modulation transfer functions, Selenium, X-rays, X-ray detectors, Digital mammography, Mammography, Amplifiers, CCD image sensors, Imaging systems

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Proceedings Article | 19 December 2001 Paper

Direct-conversion x-ray imaging detectors for medical nondestructive testing (NDT) and other applications

Denny Lee, Kelly Golden, Jeffrey Yorker, Brian Rodricks, Lawrence Cheung, Lothar Jeromin

Proceedings Volume 4508, (2001) https://doi.org/10.1117/12.450782

KEYWORDS: X-rays, Sensors, X-ray imaging, Modulation transfer functions, Selenium, X-ray detectors, Nondestructive evaluation, Image sensors, Signal to noise ratio, Radiography

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Proceedings Article | 28 June 2001 Paper

Filtered gain calibration and its effect on frequency-dependent DQE and image quality in Se-based general radiography and full-field mammographic digital imaging

Denny Lee, Brian Rodricks, Michael Hoffberg, Cornell Williams, Kelly Golden, Lothar Jeromin

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430921

KEYWORDS: Calibration, Sensors, Modulation transfer functions, X-rays, Selenium, Radiography, Digital imaging, Electrodes, Imaging systems, Optical filters

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Proceedings Article | 15 May 2001 Paper

TFT-based large-area sensor for large-format digital photography

Brian Rodricks, Michael Hoffberg, Denny Lee

Proceedings Volume 4306, (2001) https://doi.org/10.1117/12.426970

KEYWORDS: Sensors, Modulation transfer functions, Selenium, Amorphous silicon, Photography, Lamps, CCD image sensors, Cameras, Silicon, Charge-coupled devices

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Proceedings Article | 25 April 2000 Paper

Filtered gain calibration and its effect on DQE and image quality in digital imaging systems

Brian Rodricks, Denny Lee, Michael Hoffberg, Cornell Williams

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384523

KEYWORDS: Calibration, Imaging systems, Image filtering, Interference (communication), Modulation transfer functions, Digital imaging, Amplifiers, Signal to noise ratio, Image quality, Spatial filters

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Proceedings Article | 25 April 2000 Paper

Direct-conversion flat-panel x-ray imaging: reduction of noise by presampling filtration

John Rowlands, Winston Ji, Wei Zhao, Denny Lee

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384519

KEYWORDS: Sensors, Modulation transfer functions, X-rays, Imaging systems, X-ray imaging, Spatial frequencies, Electrodes, Prototyping, Photoresistors, Interference (communication)

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Proceedings Article | 25 April 2000 Paper

Development of a novel high-resolution direct conversion x-ray detector

Eric Gingold, Denny Lee, Lothar Jeromin, Brian Rodricks, Michael Hoffberg, Cornell Williams

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384492

KEYWORDS: Sensors, Modulation transfer functions, Selenium, X-ray detectors, X-rays, Radiography, Spatial resolution, Prototyping, Image sensors, Detector development

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Proceedings Article | 24 July 1998 Paper

Clinical evaluation of a full-field digital-projection radiography detector

Gary Shaber, Denny Lee, Jeffrey Bell, Gregory Powell, Andrew Maidment

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317046

KEYWORDS: Abdomen, Chest, Sensors, Radiography, X-ray imaging, X-rays, Selenium, Diagnostics, Modulation transfer functions, Image analysis

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Proceedings Article | 24 July 1998 Paper

Thin-film transistor array technology for high-performance direct-conversion x-ray sensors

Willem den Boer, Steven Aggas, Young Byun, Tieer Gu, Johnny Zhong, Scott Thomsen, Lothar Jeromin, Denny Lee

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317054

KEYWORDS: X-rays, Sensors, X-ray imaging, Capacitance, Electrodes, Digital x-ray imaging, Selenium, Transistors, Thin films, Capacitors

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Proceedings Article | 24 July 1998 Paper

Improved imaging performance of a 14"x17" direct radiography system using a Se/TFT detector

Denny Lee, Lawrence Cheung, Brian Rodricks, Gregory Powell

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317017

KEYWORDS: Sensors, Modulation transfer functions, Imaging systems, X-rays, Selenium, Radiography, Photons, X-ray detectors, Signal detection, X-ray imaging

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Proceedings Article | 24 July 1998 Paper

Selenium flat-panel detector-based volume tomographic angiography imaging: phantom studies

Ruola Ning, Denny Lee, Xiaohui Wang, Ying Zhang, David Conover, Cornell Williams

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317031

KEYWORDS: Sensors, Imaging systems, Spatial resolution, Tomography, Angiography, Image sensors, Selenium, X-rays, X-ray detectors, Thin films

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Proceedings Article | 7 May 1997 Paper

Automatic detection of the useful image data from digital x-ray detectors

Ronald Schwenker, Lothar Jeromin, Denny Lee, Cornell Williams

Proceedings Volume 3031, (1997) https://doi.org/10.1117/12.273898

KEYWORDS: Digital imaging, Image processing, X-ray detectors, Digital image processing, Detection and tracking algorithms, X-rays, Absorbance, Sensors, Diagnostics, Algorithm development

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Proceedings Article | 2 May 1997 Paper

Radiographic imaging characteristics of a direct conversion detector using selenium and thin film transistor array

Denny Lee, Lawrence Cheung, Lothar Jeromin, Eugene Palecki, Brian Rodricks

Proceedings Volume 3032, (1997) https://doi.org/10.1117/12.273973

KEYWORDS: Sensors, Modulation transfer functions, X-rays, Selenium, Radiography, Signal detection, Quantum efficiency, Interference (communication), Prototyping, Semiconductors

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Proceedings Article | 1 May 1996 Paper

Productivity improvements with a direct digital radiography system integrated with PACS

Lothar Jeromin, Denny Lee, Eugene Palecki, David Wolff

Proceedings Volume 2711, (1996) https://doi.org/10.1117/12.239255

KEYWORDS: Radiography, Picture Archiving and Communication System, X-rays, Digital imaging, Image storage, Radiology, X-ray imaging, Image transmission, X-ray detectors, Image processing

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Proceedings Article | 11 April 1996 Paper

Discussion on resolution and dynamic range of Se-TFT direct digital radiographic detector

Denny Lee, Lawrence Cheung, Eugene Palecki, Lothar Jeromin

Proceedings Volume 2708, (1996) https://doi.org/10.1117/12.237813

KEYWORDS: X-rays, Sensors, Selenium, X-ray imaging, X-ray detectors, Imaging systems, Digital imaging, Dielectrics, Capacitors, Gold

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The imaging performance of a new direct digital radiographic detector based on amorphous selenium and amorphous silicon TFT array which is under development is discussed. Progress has been made on the development of a multilayer digital x-ray detector panel with a structure consisting of a thin-film transistor pixel array, selenium x-ray photoconductor, dielectric layer and top electrode. An electronic system allows the rapid readout of image data which produces high resolution and wide dynamic range images. Using a straight edge, small wires and low contrast small holes targets, we have studied the spatial resolution, contrast detectability, and dynamic range of this new detector. Digital signals obtained from each pixel of this detector are almost linear with the total x-ray energy absorbed within the pixel area over a wide range of x-ray exposures. The resultant wide dynamic range allows extended latitude of exposure conditions and the enhancement or emphasis of different gray level regions from a single set of image data. For example, from one single exposure of the head, the soft tissue of the nose, detail structure of the teeth, as well as the bone structure of the neck can be examined by displaying and emphasizing selective gray levels of the image data. Image information obtained from this detector appears to be more evenly distributed over a wide dynamic range which is different from digital data obtained from other digital modalities such as the electrometer sensing of discharged potentials on photoconductors or from film digitization. Examples of images are shown. The discrete pixel structure of this detector and the higher intrinsic spatial resolution of selenium combine to produce image sharpness greater than those produced from digital detectors of similar pixel pitch using indirect conversion method or from digitizing film-screen images. The applicability of mathematical tools, such as the MTF which was developed primarily for analog images on a continuous imaging medium, is discussed with respect to our new discrete element detector.