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2. Functional imaging of the ocular fundus using an 8-band retinal multispectral imaging systemJ. Emanuel Ramos de Carvalho, Richelle J. M. Hoveling, Cornelis J. F. van Noorden, Reinier O. Schlingemann, Maurice C. G. Aalders, 2020, izvirni znanstveni članek Povzetek: Application of functional imaging in ophthalmology requires efficient imaging techniques that can detect and quantify chromophores to visualise processes in vivo. The aim of the present study was to develop and evaluate a fast and affordable imaging system. We describe an eight-band retinal multispectral imaging (MSI) system and compare it with a hyperspectral imaging (HSI) device. Determination of blood oxygen saturation was studied as proof of principle. Reflectance of incident light is measured as 1/absorbance at different wavelengths between 440 nm and 580 nm. Both devices have incorporated optical bandpass filters in a mydriatic fundus camera. The MSI system scans the retina at eight pre-defined wavelengths specific for the spectrum of haemoglobin. The HSI system acquires a full scan from 480 to 720 nm in 5 nm steps. A simple assessment of the ratio between the absorbance peaks of oxygenated haemoglobin (HbO2) and reduced haemoglobin (HbR) was not suitable for generating validated oxygenation maps of the retina. However, a correction algorithm that compares the measured reflectance with reflectance spectra of fully oxygenated and fully deoxygenated blood allowed our MSI setup to estimate relative oxygen saturation at higher levels, but underestimated relative oxygen saturation at lower levels. The MSI device generated better quality images than the HSI device. It allows customisation with filter sets optimised for other chromophores of interest, and augmented with extrinsic contrast imaging agents, it has the potential for a wider range of ophthalmic molecular imaging applications. Ključne besede: functional imaging, multispectral imaging, hyperspectral imaging, oximetry Objavljeno v DiRROS: 22.07.2024; Ogledov: 413; Prenosov: 266 Celotno besedilo (1,86 MB) Gradivo ima več datotek! Več... |
3. Effect of belowground deployment of entomopathogenic fungus Metarhizium brunneum on strawberry plants and aboveground pestsJaka Razinger, Darinka Koron, Špela Modic, Eva Praprotnik, Primož Žigon, Uroš Žibrat, Matej Knapič, Janez Lapajne, Andrej Vončina, Lovro Sinkovič, Nika Cvelbar Weber, 2023, drugi znanstveni članki Ključne besede: biological control, integrated pest management, agricultural entomology, entomopathogenic fungi, hyperspectral imaging, remote sensing, plant-microbe-pest interaction, plant physiology, rhizosphere competence Objavljeno v DiRROS: 27.07.2023; Ogledov: 547; Prenosov: 0 |
4. Estimating quantitative physiological and morphological tissue parameters of murine tumor models using hyperspectral imaging and optical profilometryTadej Tomanič, Luka Rogelj, Jošt Stergar, Boštjan Markelc, Tim Božič, Simona Kranjc Brezar, Gregor Serša, Matija Milanič, 2022, izvirni znanstveni članek Povzetek: Understanding tumors and their micro-environment are essential for successfuland accurate disease diagnosis. Tissuephysiology and morphology are altered intumors compared to healthy tissues, andthere is a need to monitor tumors and their surrounding tissues, includingblood vessels, non-invasively. This preliminary study utilizes a multimodaloptical imaging system combining hyperspectral imaging (HSI) and three-dimensional (3D) optical profilometry (OP) to capture hyperspectral imagesand surface shapes of subcutaneously grown murine tumor models. Hyper-spectral images are corrected with 3D OP data and analyzed using the inverse-adding doubling (IAD) method to extract tissue properties such as melaninvolume fraction and oxygenation. Blood vessels are segmented using theB-COSFIRE algorithm from oxygenation maps. From 3D OP data, tumor vol-umes are calculated and compared to manual measurements using a verniercaliper. Results show that tumors can be distinguished from healthy tissuebased on most extracted tissue parameters (p<0:05). Furthermore, blood oxy-genation is 50% higher within the blood vessels than in the surrounding tissue,and tumor volumes calculated using 3D OP agree within 26% with manualmeasurements using a vernier caliper. Results suggest that combining HSI andOP could provide relevant quantitative information about tumors and improvethe disease diagnosis. Ključne besede: medical physics, hyperspectral imaging, diffuse reflectance spectroscopy, blood vessels, tumors Objavljeno v DiRROS: 08.09.2022; Ogledov: 714; Prenosov: 246 Celotno besedilo (3,79 MB) |
5. Comparison of selected dimensionality reduction methods for detection of root-knot nematode infestations in potato tubers using hyperspectral imagingJanez Lapajne, Matej Knapič, Uroš Žibrat, izvirni znanstveni članek Ključne besede: hyperspectral imaging, dimensionality reduction, LDA, PLS, PCA, RandomForest, ReliefF, XGB, Meloidogyne, Solanum tuberosum Objavljeno v DiRROS: 06.09.2022; Ogledov: 665; Prenosov: 247 Celotno besedilo (1,79 MB) |
6. Discrimination between abiotic and biotic drought stress in tomatoes using hyperspectral imagingNik Susič, Uroš Žibrat, Saša Širca, Polona Strajnar, Jaka Razinger, Matej Knapič, Andrej Vončina, Gregor Urek, Barbara Gerič Stare, izvirni znanstveni članek Povzetek: Crop plants are subjected to various biotic and abiotic stresses. Both root-knot nematodes (biotic stress) and water deficiency (abiotic stress) lead to similar drought symptoms in the plant canopy. In this work, hyperspectral imaging was used for early detection of nematode infestation and water deficiency (drought) stress in tomato plants. Hyperspectral data in the range from 400 to 2500 nm of plants subjected to different watering regimes and nematode infestation levels were analysed by partial least squares – discriminant analysis (PLS-DA) and partial least squares – support vector machine (PLS-SVM) classification. PLS-SVM classification achieved up to 100% accuracy differentiating between well-watered and water-deficient plants, and between 90 and 100% when identifying nematode-infested plants. Grouping the data according to the time of imaging increased the accuracy of classification. Shortwave infrared spectral regions associated with the OH and CH stretches were most relevant for the identification of nematode infested plants and severity of infestation. This study demonstrates the capability of hyperspectral imaging to identify and discriminate between biotic and abiotic plant stresses. Ključne besede: nematode, Hyperspectral imaging, Drought stress, Root-knot nematode, Tomato Objavljeno v DiRROS: 20.07.2018; Ogledov: 4107; Prenosov: 2556 Celotno besedilo (847,87 KB) Gradivo ima več datotek! Več... |