Dr. Ünal Sakoglu Profile

Dr. Ünal Sakoglu

SPIE Involvement:

Author

Area of Expertise:

Brain Imaging Data Analysis , Pattern Recognition / Machine Learning, , Infrared Imaging , Image/Signal Processing , Remote Sensing , Neuroimaging / Brain Imaging

Websites:

Personal Website | Company Website

Proceedings Article | 11 August 2021 Presentation + Paper

Methane gas leak quantification employing infrared sensing at suspected leak sites

Paul LeVan, Unal Sakoglu

Proceedings Volume 11831, 118310G (2021) https://doi.org/10.1117/12.2595775

KEYWORDS: Sensors, Methane, Optical filters, Signal detection, Infrared sensors, Black bodies, Satellites, Remote sensing, Photodiodes, Mercury cadmium telluride

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Proceedings Article | 5 August 2021 Presentation

Algebraic nonuniformity correction for infrared imagery using a hexagonal coordinate scheme

Ünal Sakoglu

Proceedings Volume 11831, 1183108 (2021) https://doi.org/10.1117/12.2596384

KEYWORDS: Nonuniformity corrections, Infrared imaging, Infrared radiation, Algorithm development, Mid-IR, Imaging systems, Device simulation, Computer simulations, Cameras

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Proceedings Article | 22 August 2020 Presentation + Paper

Infrared sensing technologies assisting environmental monitoring

Paul LeVan, Unal Sakoglu

Proceedings Volume 11503, 115030B (2020) https://doi.org/10.1117/12.2567769

KEYWORDS: Sensors, Infrared radiation, Infrared sensors, Spectrometers, Long wavelength infrared, Remote sensing, Signal to noise ratio, Infrared technology, Environmental monitoring

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A diversified infrared technology base has been developed over the recent decades for various civilian and military sensing needs. The technology has been optimized to balance performance and affordability constraints for a variety of end-use goals. Simplistically, these goals might involve the detection and measurement of nearby, bright sources that fill even the largest angular fields-of-view of pixels in simple, low-magnification systems for which abundant signal makes possible infrared detection and measurement with less-sensitive, uncooled sensor arrays. At another extreme are ultra-cryogenically-cooled systems operating below thermoelectric cooler capabilities and which enable the detection and measurement of much fainter sources that underfill even the tiny angular pixel fields of view set by the diffraction limit of large, high magnification optical systems. Our emphasis is closer to the latter for the applications described here. As one example of the environmental monitoring capabilities made possible in the infrared, gas leak detection in transmission pipelines is vitally important for safe operation and for protecting the environment by accounting for and assessing the impact of leaks that adversely affect climate change. Gas leak detection in the infrared spectrum is facilitated by the distinctive spectral fingerprints of fundamental molecular vibrational modes which can be exploited for the detection of the gas. Sensitivity becomes paramount for many applications requiring faint signal detection, and large sensor array formats facilitate surveillance coverage. Many climate change assessments are expected to involve wide-area coverage of Earth scenes with revisit times sufficiently short to capture important transitory events. Shorter term monitoring of containment compliance requires detecting sufficiently small gas leak flows over broad expanses of the Earth’s surface with high detection sensitivities. In this paper we described supporting technologies in the areas of sensor arrays and optical sub-systems, with an emphasis on dispersive spectrometers. There are a plethora of applications involving the stewardship of a range of biological assets, both in the ocean and on land environments, as well as large-scale sensing of atmospheric properties, including concentrations of greenhouse gases.

Proceedings Article | 22 August 2020 Presentation + Paper

Development of an algebraic nonuniformity correction algorithm for hexagonally-sampled infrared imagery

Unal Sakoglu, Mark Minton

Proceedings Volume 11503, 115030A (2020) https://doi.org/10.1117/12.2568156

KEYWORDS: Nonuniformity corrections, Cameras, Infrared imaging, Algorithm development, Infrared radiation, Image resolution, Calibration, Thermography, Mid-IR

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Proceedings Article | 19 September 2016 Presentation + Paper

LWIR pupil imaging and longer-term calibration stability

Paul LeVan, Ünal Sakoglu

Proceedings Volume 9974, 99740S (2016) https://doi.org/10.1117/12.2237899

KEYWORDS: Long wavelength infrared, Calibration, Staring arrays, Nonuniformity corrections, Imaging systems, Infrared radiation, Sensors, Scene based nonuniformity corrections, Video, Motion estimation

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Proceedings Article | 28 August 2015 Paper

LWIR pupil imaging and prospects for background compensation

Paul LeVan, Ünal Sakoglu, Mark Stegall, Greg Pierce

Proceedings Volume 9609, 96090U (2015) https://doi.org/10.1117/12.2190354

KEYWORDS: Staring arrays, Nonuniformity corrections, Telescopes, Long wavelength infrared, Imaging systems, Infrared imaging, Infrared telescopes, Infrared radiation, Black bodies, Modulation

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Proceedings Article | 29 December 2004 Paper

Quantum dot detectors for mid-infrared sensing: bias-controlled spectral tuning and matched filtering

Unal Sakoglu, Zhipeng Wang, Majeed Hayat, J. Scott Tyo, Senthil Annamalai, Philip Dowd, Sanjay Krishna

Proceedings Volume 5593, (2004) https://doi.org/10.1117/12.571326

KEYWORDS: Sensors, Optical filters, Reconstruction algorithms, Signal to noise ratio, Detection and tracking algorithms, Quantum dots, Image filtering, FT-IR spectroscopy, Spectroscopy, Black bodies

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Quantum-dot infrared photodetectors (QDIPs), based on intersubband transitions in nanoscale self-assembled dots, are perceived as a promising technology for mid-infrared-regime sensing since they are based on a mature GaAs technology, are sensitive to normal incidence radiation, exhibit large quantum confined stark effect that can be exploited for hyperspectral imaging, and have lower dark currents than their quantum well counterparts. High detectivity (D* = 1.0E11 cmHz^1/2/W at 9 microns) QDIPs have been recently shown to exhibit broad spectral responses approximately 2-micron FWHM) with a bias-dependent shift in their peak wavelengths. This controllable, bias dependent spectral diversity, in conjunction with signal-processing strategies, allows us to extend the operation of the QDIP sensors to a new modality that enables us to achieve: (1) spectral tunability (single- or multi-color) in the range 2-12 microns in the presence of the QDIP's dark current; and (2) multispectral matched filtering in the same range. The spectral tuning is achieved by forming an optimal weighted sum of multiple photocurrent measurements, taken of the object to be probed, one for each bias in a set of prescribed operational biases. For each desired spectral response, the number and values of the prescribed biases and their associated weights are tailored so that the superposition response is as close as possible, in the mean-square-error sense, to the response of a sensor that is optically tuned to the desired spectrum. The spectral matching is achieved similarly but with a different criterion for selecting the weights and biases. They are selected, in conjunction with orthogonal-subspace-projection principles in hyperspectral classification, to nullify the interfering spectral signatures and maximize the signal-to noise ratio of the output. This, in turn, optimizes the classification of the objects according to their spectral signatures. Experimental results will be presented to demonstrate the QDIP sensor's capabilities in these new modalities. The effect of dark current noise on the spectral-tuning capability is particularly investigated. Examples of narrowband and wideband multispectral photocurrent synthesis as well as matched filtering are presented.

Proceedings Article | 2 November 2004 Paper

An algebraic restoration method for estimating fixed-pattern noise in infrared imagery from a video sequence

Unal Sakoglu, Russell Hardie, Majeed Hayat, Bradley Ratliff, J. Scott Tyo

Proceedings Volume 5558, (2004) https://doi.org/10.1117/12.557902

KEYWORDS: Calibration, Sensors, Video, Cameras, Infrared imaging, Infrared radiation, Motion models, Nonuniformity corrections, Staring arrays, Matrices

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Proceedings Article | 15 October 2004 Paper

Real-time implementation of matched filtering algorithms using adaptive focal-plane array technology

Zhipeng Wang, Unal Sakoglu, Senthil Annamalai, Nina-Rae Weisse-Bernstein, Philip Dowd, J. Scott Tyo, Majeed Hayat, Sanjay Krishna

Proceedings Volume 5546, (2004) https://doi.org/10.1117/12.560116

KEYWORDS: Sensors, Space sensors, Signal to noise ratio, Staring arrays, Infrared radiation, Photodetectors, Quantum well infrared photodetectors, Infrared photography, Image processing, Spectral resolution

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Showing 5 of 9 publications

Conference Committee Involvement (6)

Infrared Sensors, Devices, and Applications XI

4 August 2021 | San Diego, California, United States

Infrared Sensors, Devices, and Applications X

24 August 2020 | Online Only, California, United States

Infrared Sensors, Devices, and Applications IX

14 August 2019 | San Diego, California, United States

Infrared Sensors, Devices, and Applications VIII

22 August 2018 | San Diego, California, United States

Infrared Sensors, Devices, and Applications VII

9 August 2017 | San Diego, California, United States

Showing 5 of 6 Conference Committees

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