Dr. Keigo Hirakawa Profile

Dr. Keigo Hirakawa

Professor at Univ of Dayton

SPIE Involvement:

Author

Publications (16)

Proceedings Article | 7 June 2024 Presentation + Paper

Micropolarizer array demosaicking and denoising

Joseph Raffoul, Daniel LeMaster, Keigo Hirakawa

Proceedings Volume 13050, 1305004 (2024) https://doi.org/10.1117/12.3015494

KEYWORDS: Denoising, Wavelets, Polarimetry, Image analysis, Wavelet transforms, Modulation, Image restoration, Image quality, Sensors, Reflection

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Proceedings Article | 7 June 2024 Presentation + Paper

Experimental comparison of 2x2 and 2x4 patterned microgrid polarimetric imaging cameras

Keigo Hirakawa, Daniel LeMaster, Joseph Raffoul, David Chenault, David Crandall, J. Larry Pezzaniti

Proceedings Volume 13050, 1305003 (2024) https://doi.org/10.1117/12.3013761

KEYWORDS: Cameras, Polarimetry, Aliasing, Modulation transfer functions, Infrared cameras, Image restoration, Reflection, Prototyping, Sensor technology

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Proceedings Article | 3 October 2023 Presentation + Paper

Single-shot spectroscopy using continuously variable filters

Roseanna Lawandi, Zhanibek Bolatbek, Imad Agha, Keigo Hirakawa, Andrew Sarangan

Proceedings Volume 12653, 1265307 (2023) https://doi.org/10.1117/12.2681657

KEYWORDS: Tunable filters, Signal filtering, Optical filters, Film thickness, Detector arrays, Spectroscopy, Fabrication, Dielectric filters, Linear filtering, Fabry–Perot interferometers

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Proceedings Article | 15 June 2023 Poster

A Tunable transmission filter using Phase Change Materials (PCM) for smart IR night vision applications

Remona Heenkenda, Keigo Hirakawa, Andrew Sarangan

Proceedings Volume 12514, 125140I (2023) https://doi.org/10.1117/12.2670243

KEYWORDS: Tunable filters, Optical filters, Night vision, Industrial applications, Near infrared, Infrared imaging, Visible radiation, Silicon, Design and modelling, Titanium dioxide

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Proceedings Article | 22 May 2023 Presentation + Paper

Computationally efficient and high fidelity log-based demosaicking for degree of linear polarization

Joseph Raffoul, Daniel LeMaster, Keigo Hirakawa

Proceedings Volume 12327, 123270Y (2023) https://doi.org/10.1117/12.2641706

KEYWORDS: Polarization, Reconstruction algorithms, Signal to noise ratio, Linear filtering, Sensors, Polarizers, Polarimetry, Image interpolation

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SPIE Journal Paper | 4 March 2021

Color-compressive bilateral filter and nonlocal means for high-dimensional images

Christina Karam, Kenjiro Sugimoto, Keigo Hirakawa

JEI, Vol. 30, Issue 02, 023001, (March 2021) https://doi.org/10.1117/12.10.1117/1.JEI.30.2.023001

KEYWORDS: Optical filters, Image filtering, Convolution, Image processing, Hyperspectral imaging, Denoising, Stochastic processes, Linear filtering, Gaussian filters, Digital filtering

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Proceedings Article | 21 August 2020 Presentation

Spectroscopy using tunable liquid crystal Fourier filters

Roseanna Lawandi, Keigo Hirakawa, Andrew Sarangan

Proceedings Volume 11467, 114670O (2020) https://doi.org/10.1117/12.2567658

KEYWORDS: Liquid crystals, Optical filters, Spectroscopy, Tunable filters, Dielectric filters, Photodetectors, Dielectrics, Electronic filtering, Fabrication, Thin films

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SPIE Journal Paper | 24 July 2020

Improved photometric acceptance testing in image feature extraction tasks

ElHusain Saad, Keigo Hirakawa

JEI, Vol. 29, Issue 04, 043012, (July 2020) https://doi.org/10.1117/12.10.1117/1.JEI.29.4.043012

KEYWORDS: Sensors, Feature extraction, Testing and analysis, Stars, Statistical modeling, Solids, Mirrors, Light sources and illumination, Target detection

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Proceedings Article | 3 September 2019 Presentation + Paper

Fabrication of integrated single-chip Fourier spectrometers

Roseanna Lawandi, Keigo Hirakawa, Partha Banerjee, Andrew Sarangan

Proceedings Volume 11089, 110890V (2019) https://doi.org/10.1117/12.2529798

KEYWORDS: Photodetectors, Sensors, Silicon, Optical filters, Spectrometers, Optical lithography, Dielectrics

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Proceedings Article | 26 September 2016 Presentation + Paper

Design and fabrication of Fourier spectral filter array for multispectral imaging

Chuan Ni, Jie Jia, Keigo Hirakawa, Andrew Sarangan

Proceedings Volume 9927, 99270W (2016) https://doi.org/10.1117/12.2238864

KEYWORDS: Multispectral imaging, Optical filters, Image filtering, Imaging arrays, RGB color model, Transmittance, Photomasks, Zinc, Photoresist materials, Image sensors

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Proceedings Article | 20 August 2015 Presentation + Paper

Design and fabrication of sinusoidal spectral filters for multispectral imaging

Chuan Ni, Jie Jia, Keigo Hirakawa, Andrew Sarangan

Proceedings Volume 9556, 95560I (2015) https://doi.org/10.1117/12.2188830

KEYWORDS: Optical filters, Multispectral imaging, Zinc, Fabry–Perot interferometers, Refractive index, Manufacturing, Image filtering, Reflectivity, Sputter deposition, Design for manufacturability

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Proceedings Article | 21 May 2014 Paper

Fourier domain design of microgrid imaging polarimeters with improved spatial resolution

Keigo Hirakawa, Daniel LeMaster

Proceedings Volume 9099, 909906 (2014) https://doi.org/10.1117/12.2053475

KEYWORDS: Spatial resolution, Polarimetry, Modulation, Polarization, Imaging systems, Fourier transforms, Analytical research, Spatial frequencies, Image resolution, Remote sensing

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Proceedings Article | 19 February 2013 Paper

Approximations to camera sensor noise

Xiaodan Jin, Keigo Hirakawa

Proceedings Volume 8655, 86550H (2013) https://doi.org/10.1117/12.2019212

KEYWORDS: Sensors, Interference (communication), Data modeling, Wavelets, Image sensors, Cameras, Stochastic processes, Quantization, Image denoising, Signal to noise ratio

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Proceedings Article | 3 February 2009 Paper

Wavelet-based Poisson rate estimation using the Skellam distribution

Keigo Hirakawa, Farhan Baqai, Patrick Wolfe

Proceedings Volume 7246, 72460R (2009) https://doi.org/10.1117/12.815487

KEYWORDS: Statistical analysis, Signal processing, Wavelets, Radon, Stochastic processes, Electronics, Data communications, Astronomy, Magnetic resonance imaging, Filtering (signal processing)

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Proceedings Article | 28 January 2008 Paper

Second-generation color filter array and demosaicking designs

Keigo Hirakawa, Patrick Wolfe

Proceedings Volume 6822, 68221P (2008) https://doi.org/10.1117/12.767058

KEYWORDS: Sensors, Optical filters, Cameras, Spatial resolution, Modulation, Digital cameras, Image sensors, Image processing, Demodulation, Image quality

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Proceedings Article | 20 September 2007 Paper

Signal-dependent noise characterization in Haar filterbank representation

Keigo Hirakawa

Proceedings Volume 6701, 67011I (2007) https://doi.org/10.1117/12.735290

KEYWORDS: Interference (communication), Signal processing, Electronic filtering, Filtering (signal processing), Statistical analysis, Data modeling, Statistical modeling, Error analysis, Wavelets, Time-frequency analysis

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Showing 5 of 16 publications

Conference Committee Involvement (5)

Visual Information Processing and Communication VI

10 February 2015 | San Francisco, California, United States

Visual Information Processing and Communication V

5 February 2014 | San Francisco, California, United States

Visual Information Processing and Communication IV

6 February 2013 | Burlingame, California, United States

Visual Information Processing and Communication III

24 January 2012 | Burlingame, California, United States

Visual Information Processing and Communication II

25 January 2011 | San Francisco Airport, California, United States

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