| 1. |
- Brydegaard, Mikkel, et al.
(författare)
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Photobleaching-Insensitive Fluorescence Diagnostics in Skin and Brain Tissue
- 2011
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Ingår i: IEEE Photonics Journal. - : Institute of Electrical and Electronics Engineers. - 1943-0655. ; 3:3, s. 407-421
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the possibility of using accurate prediction models for the prediction of protoporphyrin bleaching dynamics to achieve photobleaching-insensitive methods to improve the evaluation of data in an existing clinical fluorescence-guided resection technique. To simulate the scenario, measurements were carried out in vivo on skin of healthy volunteers using a compact fiber-based fluorescence spectroscopy system. We have developed an effective method for the parameterization of sequences of bleaching spectra. We analyze convergence and decay rates with respect to initial conditions and excitation irradiance. We also discuss the consequences and the potential for bleaching-insensitive measurements and their applicability in a few examples from in vivo open brain surgery.
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| 2. |
- Brydegaard, Mikkel, et al.
(författare)
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Versatile multispectral microscope based on light emitting diodes.
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 82:12
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Tidskriftsartikel (refereegranskat)abstract
- We describe the development of a novel multispectral microscope, based on light-emitting diodes, capable of acquiring megapixel images in thirteen spectral bands from the ultraviolet to the near infrared. The system captures images and spectra in transmittance, reflectance, and scattering modes. We present as examples of applications ground truth measurements for remote sensing and parasitology diagnostics. The system is a general purpose scientific instrument that could be used to develop dedicated simplified instruments with optimal bands and mode selection.
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| 3. |
- Lundin, Patrik, et al.
(författare)
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Passive unmanned sky spectroscopy for remote bird classification
- 2011
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Ingår i: Remote Sensing For Agriculture, Ecosystems, And Hydrology XIII. - : SPIE. - 0277-786X .- 1996-756X. ; 8174
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Konferensbidrag (refereegranskat)abstract
- We present a method based on passive spectroscopy with aim to remotely study flying birds. A compact spectrometer is continuously recording spectra of a small section of the sky, waiting for birds to obscure part of the field-of-view when they pass the field in flight. In such situations the total light intensity received through the telescope, looking straight up, will change very rapidly as compared to the otherwise slowly varying sky light. On passage of a bird, both the total intensity and the spectral shape of the captured light changes notably. A camera aimed in the same direction as the telescope, although with a wider field-of-view, is triggered by the sudden intensity changes in the spectrometer to record additional information, which may be used for studies of migration and orientation. Example results from a trial are presented and discussed. The study is meant to explore the information that could be gathered and extracted with the help of a spectrometer connected to a telescope. Information regarding the color, size and height of flying birds is discussed. Specifically, an application for passive distance determination utilizing the atmospheric oxygen A-band absorption at around 760 nm is discussed.
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| 4. |
- Lundin, Patrik, et al.
(författare)
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Remote nocturnal bird classification by spectroscopy in extended wavelength ranges
- 2011
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Ingår i: Applied Optics. - 2155-3165. ; 50:20, s. 3396-3411
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Tidskriftsartikel (refereegranskat)abstract
- We present optical methods at a wide range of wavelengths for remote classification of birds. The proposed methods include eye-safe fluorescence and depolarization lidar techniques, passive scattering spectroscopy, and infrared (IR) spectroscopy. In this paper we refine our previously presented method of remotely classifying birds with the help of laser-induced beta-keratin fluorescence. Phenomena of excitation quenching are studied in the laboratory and are theoretically discussed in detail. It is shown how the ordered microstructures in bird feathers induce structural "colors" in the IR region with wavelengths of around 3-6 mu m. We show that transmittance in this region depends on the angle of incidence of the transmitted light in a species-specific way and that the transmittance exhibits a close correlation to the spatial periodicity in the arrangement of the feather barbules. We present a method by which the microstructure of feathers can be monitored in a remote fashion by utilization of thermal radiation and the wing beating of the bird. (C) 2011 Optical Society of America
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| 5. |
- Thompson, Alex, et al.
(författare)
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Hyperspectral fluorescence lifetime fibre probe spectroscopy for use in the study and diagnosis of osteoarthritis and skin cancer
- 2011
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Ingår i: Optical Biopsy IX. - : SPIE. - 1605-7422. - 9780819484321 ; 7895
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Konferensbidrag (refereegranskat)abstract
- We present the application of two fibre-optic-coupled time-resolved spectrofluorometers and a compact steady-state diffuse reflected light/fluorescence spectrometer to in vivo and ex vivo studies of skin cancer and osteoarthritis. In a clinical study of skin cancer, 27 lesions on 25 patients were investigated in vivo before surgical excision of the region measured. Preliminary analysis reveals a statistically significant decrease in the autofluorescence lifetime of basal cell carcinomas compared to neighbouring healthy tissue. A study of autofluorescence signals associated with the onset of osteoarthritis indicates autofluorescence lifetime changes associated with collagen degradation.
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