Fourier multispectral imaging

Jia, Jie; Ni, Chuan; Sarangan, Andrew; Hirakawa, Keigo

doi:10.1364/oe.23.022649

Cited by 16 publications

(4 citation statements)

References 22 publications

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“…Appealing to the fact that each interferometric measurement is equivalent to taking inner product between a sinusoidal function and the full spectrum in the wavenumber domain, we replaced the narrowband filter with broadband filters whose transmittance follows sinusoidal shape, a process by which we obtain interferometric measurements at every pixel. We proved that Fourier spectroscopy-based MSI preserves spectral features more accurately than the narrowband MSI [11], and proposed spatial arrangements of SFA using these sinusoidal filters (hereafter referred to as Fourier SFA) [10]. In our earlier work, less emphasis was placed on the demosaicking procedure.…”

Section: Introductionmentioning

confidence: 86%

Guided Filter Demosaicking For Fourier Spectral Filter Array

Jia¹,

Ni²,

Sarangan³

et al. 2016

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Section: Introductionmentioning

confidence: 86%

Guided Filter Demosaicking For Fourier Spectral Filter Array

Jia¹,

Ni²,

Sarangan³

et al. 2016

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“…A low-index film will produce a more ideal sinusoidal shape, but will suffer from a low modulation ratio. 5 In our earlier work, we used sputtered ZnS for this application. However, for glancing angle deposition, we have to use thermal evaporation, and a better material for evaporation with similar properties is WO 3 .…”

Section: Design and Simulationmentioning

confidence: 99%

“…CMOS cameras) 3,4 in order to spatially separate the spectral content of the incident light into narrowband measurements. In an earlier work, we introduced the concept of Fourier filters, 5,6 where broadband sinusoidally varying spectral filters are used to resolve the spectral content of light with a high overall transmission compared to narrow band filters. When detecting narrowband spectral features (such as emmission bands) these filters were shown to require fewer number of filters compared to the conventional narrowband measurements.…”

Section: Introductionmentioning

confidence: 99%

Single-shot spectroscopy using continuously variable filters

Lawandi,

Bolatbek,

Agha

et al. 2023

Nanoengineering: Fabrication, Properties, Optics, Thin Films, and Devices XX

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Spectroscopic measurements are used in increasingly diverse areas of manufacturing, disease detection, food quality inspection, indoor lighting control, etc. Commonly used spectral decomposition methods utilize several discrete dispersive optical elements to split the incoming light into its frequency components and direct them onto a linear photodetector array. In our previous work, we demonstrated that such mechanically fragile systems can be replaced by thin film dielectric Fourier spectral filters. However, the main disadvantage of this technique is the need for multiple filters with varying dielectric Fabry-Perot cavity lengths, which requires extensive fabrication processes to lithographically pattern and etch. In this work, we demonstrate a novel fabrication of a continuously variable filter, using glancing angle deposition, that can produce 10× more Fourier filters in a single deposition run without the need for lithographic patterning. We apply this method to a commercial off-the-shelf 38-channel linear photodetector array and demonstrate the ability to quickly decompose the incoming signal using only half of the available channels. This novel technique has the potential to enable highly compact and highly robust spectrometers that could be integrated into many handheld devices

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“…A potential fourth strategy is to maximize the bandwidth Λ ∞ and explore different filter designs. This implies using computational approaches to enable the use of broadband filters with, for example, sinusoidal transmittance [31]. Note that the trade-off parameter was derived for narrowband filters.…”

Section: Mitigation Strategies For Snapshot Spectral Imagingmentioning

confidence: 99%

Pixel-integrated thin-film filter simulation and scaling trade-offs

Goossens

2021

Preprint

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Thin-film optical filters can nowadays be integrated onto pixels of commercial image sensors used for spectral imaging. A drawback of having more filters on an image sensor is a loss in spatial resolution which could be regained by using smaller pixels. However, this work shows that miniaturization causes a reduction in transmittance and requires a trade-off between pixel size and filter bandwidth. This is caused by diffraction and the reduced number of reflections in the filter. Analytical wave and ray optics models are developed and used for fast transmittance prediction and this is validated using a commercial spectral sensor and numerical simulations. The identified trade-off is an intrinsic limitation of pixel-integrated thin-film filter technology and the developed models will be useful tools for exploring new hardware and computational solutions.

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Fourier multispectral imaging

Cited by 16 publications

References 22 publications

Guided Filter Demosaicking For Fourier Spectral Filter Array

Guided Filter Demosaicking For Fourier Spectral Filter Array

Single-shot spectroscopy using continuously variable filters

Pixel-integrated thin-film filter simulation and scaling trade-offs

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