| 1. |
- Bao, Yupan, et al.
(författare)
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Single-shot 3D imaging of hydroxyl radicals in the vicinity of a gliding arc discharge
- 2021
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Ingår i: Plasma Sources Science and Technology. - : IOP Publishing. - 0963-0252 .- 1361-6595. ; 30:4
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Tidskriftsartikel (refereegranskat)abstract
- Chemical processing by plasma is utilized in many applications. Plasma-related studies, however, are challenging to carry out due to plasmas' transient and unpredictable behavior, excessive luminosity emission, 3D complexity and aggressive chemistry and physiochemical interactions that are easily affected by external probing. Laser-induced fluorescence is a robust technique for non-intrusive investigations of plasma-produced species. The hydroxyl radical (OH) is an interesting molecule to target, as it is easily produced by plasmas in humid air. In this letter, we present 3D distributions of ground state OH radicals in the vicinity of a glow-type gliding arc plasma. Such radical distributions, with minimal plasma emission, are captured instantaneously in one single camera acquisition by combining structured laser illumination and a lock-in based imaging analysis method called FRAME. The orientation of the plasma discharge can be reconstructed from the 3D data matrix, which can then be used to calculate 2D distributions of ground state OH radicals in a plane perpendicular to the orientation of the plasma channel. Our results indicate that OH distributions around a gliding arc are strongly affected by gas dynamics. We believe that the ability to instantaneously capture 3D transient molecular distributions in a plasma discharge, with minimal plasma emission interference, will have a strong impact on the plasma community for in-situ investigations of plasma-induced chemistry and physics.
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| 2. |
- Dorozynska, Karolina, et al.
(författare)
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A versatile, low-cost, snapshot multidimensional imaging approach based on structured light
- 2020
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Ingår i: Optics Express. - 1094-4087. ; 28:7, s. 9572-9586
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Tidskriftsartikel (refereegranskat)abstract
- The behaviour and function of dynamic samples can be investigated using optical imaging approaches with high temporal resolution and multidimensional acquisition. Snapshot techniques have been developed in order to meet these demands, however they are often designed to study a specific parameter, such as spectral properties, limiting their applicability. Here we present and demonstrate a frequency recognition algorithm for multiple exposures (FRAME) snapshot imaging approach, which can be reconfigured to capture polarization, temporal, depthof- focus and spectral information by simply changing the filters used. FRAME is implemented by splitting the emitted light from a sample into four channels, filtering the light and then applying a unique spatial modulation encoding before recombining all the channels. The multiplexed information is collected in a single exposure using a single detector and extracted in post processing of the Fourier transform of the collected image, where each channel image is located in a distinct region of the Fourier domain. The approach allows for individual intensity control in each channel, has easily interchangeable filters and can be used in conjunction with, in principle, all 2D detectors, making it a low cost and versatile snapshot multidimensional imaging technique.
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| 3. |
- Dorozynska, Karolina D., et al.
(författare)
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A coded illumination scheme for single exposure (instantaneous) multispectral imaging
- 2016
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Ingår i: 2016 Conference on Lasers and Electro-Optics, CLEO 2016. - Washington, D.C. : OSA. - 9781943580118
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Konferensbidrag (refereegranskat)abstract
- We present the development of an instantaneous multispectral imaging technique exploiting spatially modulated light. Each encoded excitation source produces an image with a predefined position in the Fourier domain, allowing them to be separated computationally.
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| 4. |
- Dorozynska, Karolina D., et al.
(författare)
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A single exposure (instantaneous) multispectral microscopy scheme using structured illumination
- 2016
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Ingår i: Mathematics in Imaging, MATH 2016. - 9781943580156 ; Part F11-MATH 2016
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Konferensbidrag (refereegranskat)abstract
- We present the initial results from the development of an instantaneous multispectral microscopy technique exploiting spatially modulated light. Fluorescence from two excitation sources is recorded in a single exposure and separated in the Fourier domain.
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| 5. |
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| 6. |
- Dorozynska, Karolina
(författare)
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Frequency Recognition Algorithm for Multiple Exposures : Snapshot imaging using coded light
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The central challenge tackled in this thesis is the development of an optical imaging approach capable of multidimensional image capture of dynamic samples. Many conventional optical imaging approaches, which can obtain dimensional information such as spectral, polarisation, or volumetric, to name a few, about samples either employ sequential image capture or parallelised detector arrangements. Due to the motion of dynamic samples the use of such imaging approaches encounter difficulties. Multidimensional information therefore needs to be obtained in a single exposure in order to avoid inaccurate image reconstruction, poor image overlap and artefacts due to motion blur.\\ \noindent Snapshot techniques acquire multidimensional information in a single detector exposure and have been developed to meet the requirements for dynamic sample imaging. These approaches take many different forms, such as; the use of integrated camera sensor filter arrays, dispersive elements, lenslet arrays and coded light. In many of these cases there are constraints imposed, such as on the spectral resolution achievable or the number of unique images obtainable, by the manufacturing limits of the components required. In this thesis an alternative and novel snapshot imaging approach is presented which can intrinsically overcome some of the limitations of existing snapshot solutions available.\\ \noindent This thesis presents a snapshot imaging method called FRAME (Frequency Recognition Algorithm for Multiple Exposures). FRAME uses spatial modulation patterns to encode different dimensional information about samples so that multiple images can be captured in a single camera exposure. Using a Fourier filtering approach the different encoded images can be isolated and extracted from the multiplexed image. As a result the approach is compatible with dynamic sample imaging. The work presented demonstrates the use of FRAME for multispectral, polarisation, extended depth of focus, temporal, and volumetric imaging. Additionally, convincing results exemplifying FRAMEs more notable attributes, are presented. These include the ability to distinguish florescence emissions resulting from spectrally close (3nm) excitation sources, successful distinction of simultaneously acquired strongly spectrally overlapping florescence signals from four fluorophores, and also from as many as nine different fluorophores. These latter features can be of great benefit for applications involving fluorescence imaging.
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| 7. |
- Dorozynska, Karolina, et al.
(författare)
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Implementation of a multiplexed structured illumination method to achieve snapshot multispectral imaging
- 2017
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Ingår i: Optics Express. - 1094-4087. ; 25:15, s. 17211-17226
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Tidskriftsartikel (refereegranskat)abstract
- An instantaneous multispectral imaging setup based on frequency recognition algorithm for multiple exposures (FRAME) is presented and demonstrated experimentally. With this implementation of FRAME, each light source is uniquely encoded with a spatial modulation and the corresponding fluorescent responses pertaining to each maintain the same unique encoding. This allows the extraction of each source response from a single captured image by filtering in the Fourier domain. As a result, a multispectral imaging system based on FRAME can perform all the illumination and corresponding fluorescence detection simultaneously, where the latter is recorded in a single exposure and on a single detector and is thus capable of recording true ‘snapshot’ multispectral images. The results presented here demonstrate that the technique is capable of distinguishing source responses for well separated and co-localized fluorophores as well as providing z-sectioning capabilities. This implementation of FRAME demonstrates its viability as a tool for multispectral imaging of dynamic samples. Additionally, since all the spectral images are captured simultaneously, the method has potential for studying samples prone to photobleaching. Finally, this application of FRAME makes it possible to discriminate between signals due to infinitely spectrally close sources which, to the best of the authors’ knowledge, has not been possible in snapshot multispectral imaging schemes before.
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| 8. |
- Dorozynska, Karolina, et al.
(författare)
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Snapshot multicolor fluorescence imaging using double multiplexing of excitation and emission on a single detector
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescence-based multispectral imaging of rapidly moving or dynamic samples requires both fast two-dimensional data acquisition as well as sufficient spectral sensitivity for species separation. As the number of fluorophores in the experiment increases, meeting both these requirements becomes technically challenging. Although several solutions for fast imaging of multiple fluorophores exist, they all have one main restriction; they rely solely on spectrally resolving either the excitation- or the emission characteristics of the fluorophores. This inability directly limits how many fluorophores existing methods can simultaneously distinguish. Here we present a snapshot multispectral imaging approach that not only senses the excitation and emission characteristics of the probed fluorophores but also all cross term combinations of excitation and emission. To the best of the authors’ knowledge, this is the only snapshot multispectral imaging method that has this ability, allowing us to even sense and differentiate between light of equal wavelengths emitted from the same fluorescing species but where the signal components stem from different excitation sources. The current implementation of the technique allows us to simultaneously gather 24 different spectral images on a single detector, from which we demonstrate the ability to visualize and distinguish up to nine fluorophores within the visible wavelength range.
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