| 1. |
- Kirkeby, Carsten, et al.
(författare)
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Advances in automatic identification of flying insects using optical sensors and machine learning
- 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
- Worldwide, farmers use insecticides to prevent crop damage caused by insect pests, while they also rely on insect pollinators to enhance crop yield and other insect as natural enemies of pests. In order to target pesticides to pests only, farmers must know exactly where and when pests and beneficial insects are present in the field. A promising solution to this problem could be optical sensors combined with machine learning. We obtained around 10,000 records of flying insects found in oilseed rape (Brassica napus) crops, using an optical remote sensor and evaluated three different classification methods for the obtained signals, reaching over 80% accuracy. We demonstrate that it is possible to classify insects in flight, making it possible to optimize the application of insecticides in space and time. This will enable a technological leap in precision agriculture, where focus on prudent and environmentally-sensitive use of pesticides is a top priority.
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| 2. |
- Barup, Kerstin, et al.
(författare)
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Multi-disciplinary lidar applications
- 2010
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Ingår i: Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2010. - 2162-2701. - 9781557528803
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Konferensbidrag (refereegranskat)abstract
- Lidar is a powerful technique normally associated with atmospheric monitoring. However, lidar techniques, also of the laser-induced fluorescence and laser-induced breakdown spectroscopy varieties, provide many new possibilities in unconventional fields including cultural heritage and ecological applications.
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| 3. |
- Boateng, Rabbi, et al.
(författare)
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Mapping of Algae on Walls with a 3D Printed Hyperspectral Fluorescence Lidar
- 2023
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Ingår i: Frontiers in Optics : Proceedings Frontiers in Optics + Laser Science 2023, FiO, LS 2023 - Proceedings Frontiers in Optics + Laser Science 2023, FiO, LS 2023. - 9781957171296
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Konferensbidrag (refereegranskat)abstract
- Mapping of algae on facades and difficult-to-reach parts of tall buildings is demonstrated using a low-cost 3D-printed hyperspectral fluorescence lidar (HSFL). The 3D-printed HSFL has the potential for rapid and cost-effective remote assessment of algae.
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| 4. |
- Boateng, Rabbi, et al.
(författare)
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Remote Vegetation Diagnostics in Ghana with a Hyperspectral Fluorescence Lidar
- 2023
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 29:4: Biophotonics, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Spectral imaging and lidar methods for the characterization of vegetation are vital for understanding plants and, in turn, food security, biodiversity, and vegetation health in a changing climate. While novel hyperspectral imaging, canopy lidar,and solar-induced fluorescence provide details on species, state, structure, and plant physiology, such data come from different instruments. Thus, post-processing and data fusion struggles with synchronization, spatial overlap, and resolution issues. Especially in the tropical regions of sub-Saharan Africa, these complex, expensive, and bulky instruments remain inaccessible. Here, in Ghana, we have built a low-cost, lightweight, and realistic instrument for simultaneously acquiring hyperspectral data of vegetation fluorescence and canopy structure with perfect spatial overlap. In this paper, we demonstrate the application of the hyperspectral fluorescence lidar for diagnostics and species specificity of locally significant crops. We demonstrate simultaneous range and fluorescence measurements of forest canopy, conducted in full sunlight. Our results indicate that the upper side of the leaves shows a more substantial deviation for stressed plants, whilethe lower side shows greater contrast for plant species. This new and simple tool provides a combined method for hyperspectral classification and assessment of the physiological state while also reporting the vegetation height over ground and its diversity.
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| 5. |
- Brydegaard, Mikkel
(författare)
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Advantages of shortwave infrared LIDAR entomology
- 2014
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Ingår i: Imaging and Applied Optics - Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2014. - Washington, D.C. : OSA. - 2162-2701. - 9781557523082 - 9781557523082
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Konferensbidrag (refereegranskat)abstract
- Challenges of insect monitoring is revised. I present our new lidar, and use remote dark-field monitoring as well as hyperspectral push-broom imaging to argue why lidar entomology is significantly improved when implemented at telecom wavelengths.
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| 6. |
- Brydegaard, Mikkel
(författare)
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Aspects of Optical Broad Band Spectroscopy and Information Extraction - Applications in Medicine and Ecology
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present thesis describes a number of aspects of modern electro-optical measurement technology also known as bio-photonics; this includes instrumentation, applications, sample interaction and data interpretation. The methods employed operate over several domains, and light measurements are discretized both in intensity, space, angle, time, polarization and energy. Mainly the spectral domain is investigated over two orders of magnitude from deep ultraviolet to thermal infrared, and mainly broad spectral features in solid and liquid samples are studied. The intensity employed ranges from microwatts to megawatts, time processes are studied between hundred picoseconds to weeks and measurement are carried out from the micrometer scale and up to hundreds of meters. An important aspect of this thesis is the development of realistic instrumentation with the intention that research should benefit the supporting society; this is a key point for the success of academic research in the developing world but also goes hand-in-hand with innovation, commercialization and entrepreneurship in Scandinavia. For this reason the thesis also encompasses a number of patent applications filed during the thesis work. Most of these realistic setups are based on spectroscopy using inexpensive light emitting diodes. Their application for medical diagnosis has been demonstrated with fiber sensors in the context of oncology, and microscopy in relation to parasitology. The thesis also covers optical diagnostics of animal populations of different species on the habitat scale; these studies are pursued by the use of laser radar (lidar) or telescopes. In these areas novel approaches for remotely classifying marked or unmarked flying animals open for the investigation of a new type of questions in field entomology and ornithology. In optical applications for medicine as well as ecology the understanding of the light interaction with complex biological tissue types is essential. Several aspects of such interaction are treated in the thesis. The complex optical interrogation together with the broad and overlapping spectral features in solid samples implies that an empirical approach of data evaluation and computer learning is often more valuable than forward modeling of expected signals. An ongoing theme throughout this thesis is data reduction and chemometrical evaluation. Here discrete light measurements and linear algebra form the basis for advanced statistical evaluation. This applies to the spectral domain where redundancy can be removed, but also topics such as dynamical processes and texture analysis are approached in the temporal and spatial domains, respectively.
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| 7. |
- Brydegaard, Mikkel, et al.
(författare)
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Broad-band multispectral microscope for imaging transmission spectroscopy employing an array of light-emitting diodes
- 2009
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Ingår i: American Journal of Physics. - : American Association of Physics Teachers (AAPT). - 0002-9505 .- 1943-2909. ; 77:2, s. 104-110
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Tidskriftsartikel (refereegranskat)abstract
- Optical spectral analysis and multispectral imaging provide powerful means for characterizing samples in a wide variety of applications and on many spatial scales. We present a simple implementation of these techniques in the context of microscopy. A modified commercial microscope equipped with a CMOS imaging detector, combined with an array of light emitting diodes with emission ranging from ultraviolet to near-infrared wavelengths, is described, and examples of information enhancement using multivariate analysis are presented.
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| 8. |
- Brydegaard, Mikkel, et al.
(författare)
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Can the narrow red bands of dragonflies be used to perceive wing interference patterns?
- 2018
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 8:11, s. 5369-5384
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Tidskriftsartikel (refereegranskat)abstract
- Despite numerous studies of selection on position and number of spectral vision bands, explanations to the function of narrow spectral bands are lacking. We investigate dragonflies (Odonata), which have the narrowest spectral bands reported, in order to investigate what features these narrow spectral bands may be used to perceive. We address whether it is likely that narrow red bands can be used to identify conspecifics by the optical signature from wing interference patterns (WIPs). We investigate the optical signatures of Odonata wings using hyperspectral imaging, laser profiling, ellipsometry, polarimetric modulation spectroscopy, and laser radar experiments. Based on results, we estimate the prospects for Odonata perception of WIPs to identify conspecifics in the spectral, spatial, intensity, polarization, angular, and temporal domains. We find six lines of evidence consistent with an ability to perceive WIPs. First, the wing membrane thickness of the studied Odonata is 2.3 μm, coinciding with the maximal thickness perceivable by the reported bandwidth. Second, flat wings imply that WIPs persist from whole wings, which can be seen at a distance. Third, WIPs constitute a major brightness in the visual environment only second after the solar disk. Fourth, WIPs exhibit high degree of polarization and polarization vision coincides with frontal narrow red bands in Odonata. Fifth, the angular light incidence on the Odonata composite eye provides all prerequisites for direct assessment of the refractive index which is associated with age. Sixth, WIPs from conspecifics in flight make a significant contribution even to the fundamental wingbeat frequency within the flicker fusion bandwidth of Odonata vision. We conclude that it is likely that WIPs can be perceived by the narrow red bands found in some Odonata species and propose future behavioral and electrophysiological tests of this hypothesis.
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| 9. |
- Brydegaard, Mikkel, et al.
(författare)
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Chemometric approach to chromatic spatial variance. Case study: patchiness of the Skyros wall lizard
- 2012
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Ingår i: Journal of Chemometrics. - : Wiley. - 0886-9383. ; 26:6, s. 246-255
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we demonstrate how to take advantage of the large number of spatial samples provided by commercial multispectral RGB imagers. We investigate the possibility to use various multidimensional histograms and probability distributions for decomposition and predictive models. We show how these methods can be used in an example using images of different Skyros wall lizards and demonstrate improved performance in prediction of color morph compared with traditional parameterization techniques of spatial variance. Copyright (c) 2012 John Wiley & Sons, Ltd.
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| 10. |
- Brydegaard, Mikkel, et al.
(författare)
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Complete parameterization of temporally and spectrally resolved laser induced fluorescence data with applications in bio-photonics
- 2015
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Ingår i: Chemometrics and Intelligent Laboratory Systems. - : Elsevier BV. - 0169-7439. ; 142, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- We present a set of spectrally and temporally resolved clinical fluorescence data-with two separate excitation wavelengths-that was recorded in vivo. We demonstrate that data in the spectral and temporal domains are in certain ways coupled and provide a method for integrated and effective parameterization of spectrally and temporally resolved fluorescence (i.e., time-resolved emission spectra). This parameterization is based on linear algebra, matrix formulation and system identification. We demonstrate how to empirically extract single exponentially decaying components and provide rectified emission spectra without prior knowledge. We investigate the potential for improved cancer diagnostics according to the reduced parameters along the various domains. In this case, in terms of cancer diagnostics, we were unable to identify any benefits of simultaneously measuring both the temporal and spectral properties of the observed fluorescence. However, we note that this may be explained by an important experimental bias present in many studies of optical cancer diagnostics, namely, that, in general, suspected lesions always differ visually from the neighboring healthy tissue. (C) 2015 Elsevier B.V. All rights reserved.
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