I-HAZE: a dehazing benchmark with real hazy and haze-free indoor images

Image dehazing has become an important computational imaging topic in the recent years. However, due to the lack of ground truth images, the comparison of dehazing methods is not straightforward, nor objective. To overcome this issue we introduce a new dataset -named I-HAZE- that contains 35 image pairs of hazy and corresponding haze-free (ground-truth) indoor images. Different from most of the existing dehazing databases, hazy images have been generated using real haze produced by a professional haze machine. For easy color calibration and improved assessment of dehazing algorithms, each scene include a MacBeth color checker. Moreover, since the images are captured in a controlled environment, both haze-free and hazy images are captured under the same illumination conditions. This represents an important advantage of the I-HAZE dataset that allows us to objectively compare the existing image dehazing techniques using traditional image quality metrics such as PSNR and SSIM

Experimental study of smouldering wildfire mitigation: spread, suppression and transition to flaming

Smouldering and flaming combustion are both important in wildfires, and one can lead to the other. Although the characteristic temperature, spread rate and power of smouldering are low compared to flaming combustion, smouldering is far more persistent. Peatland wildfires are dominated by smouldering combustion and have been reported to be some of the largest wildfires in terms of fuel consumption and pollutant emissions. Unfortunately, current fundamental understanding of smouldering wildfire is limited, resulting in ineffective mitigation strategies. In this thesis, novel experiments were developed to study three phenomena: smouldering peat fire, its suppression, and the transition from smouldering to flaming combustion. To understand the behaviour of smouldering under real conditions, the largest to-date peat wildfire experiment was conducted in Sumatra, Indonesia, investigating ignition, spread, emission and suppression. The fire was observed continuously for the first time propagating for 10 days during day and night times, and despite major rainfalls. Lab-scale experiments were conducted to study the suppression under variable flow rate and wetting agents. The minimum suppression column height at the lab-scale agrees with the field-scale experiment. The required volume of suppressant per mass of peat was constant, therefore suggesting a fundamental property, at around 5.7 L/kg-peat despite changes in flow rate and wetting agent concentration. To further understand the transition from smouldering to flaming combustion, a novel experimental rig was designed to investigate the role of wind. Compared to continuous wind exposure, transition from smouldering to flaming occurred earlier under pulse wind and depended less on sample size. The results in this thesis can help to improve prevention and mitigation efforts.Open Acces

Trajectories of Air Parcel Motions in Mars\u27 Atmosphere Computed Using HYSPLIT

An analysis of the advection of air parcels in the Martian atmosphere during the 2001 global dust storm through the use of three-dimensional trajectories is presented. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, well-known for trajectory, dispersion, and deposition modeling, and originally developed for Earth was modified for Mars to provide forward and backward trajectories. The custom HYSPLIT for Mars uses meteorological input generated by the NASA Ames Mars General Circulation Model (MGCM). The 2001 global dust storm was the earliest on record (Ls ~ 180°) and originated from local dust storms around the Hellas basin as the storm expanded asymmetrically to the east. Trajectories near Hellas and Claritas Fossae correspond with dust transport detected using satellite imagery. Forward trajectories at Ls = 184° from Hellas show flow to the south, transporting dust around the south polar cap, while after L¬s = 188° there is an eastward shift in propagation. Air parcel trajectories intersecting the surface during the dust storm may indicate the processes involved with global dust storms contributing to dust layers in the polar regions. Backward trajectories from Claritas Fossae reveal the dust activity in this region was the result of local dust storm activity instead of the propagation of dust eastward from the Hellas region

Low-cost and automated phenotyping system “Phenomenon” for multi-sensor in situ monitoring in plant in vitro culture

Background: The current development of sensor technologies towards ever more cost-effective and powerful systems is steadily increasing the application of low-cost sensors in different horticultural sectors. In plant in vitro culture, as a fundamental technique for plant breeding and plant propagation, the majority of evaluation methods to describe the performance of these cultures are based on destructive approaches, limiting data to unique endpoint measurements. Therefore, a non-destructive phenotyping system capable of automated, continuous and objective quantification of in vitro plant traits is desirable. Results: An automated low-cost multi-sensor system acquiring phenotypic data of plant in vitro cultures was developed and evaluated. Unique hardware and software components were selected to construct a xyz-scanning system with an adequate accuracy for consistent data acquisition. Relevant plant growth predictors, such as projected area of explants and average canopy height were determined employing multi-sensory imaging and various developmental processes could be monitored and documented. The validation of the RGB image segmentation pipeline using a random forest classifier revealed very strong correlation with manual pixel annotation. Depth imaging by a laser distance sensor of plant in vitro cultures enabled the description of the dynamic behavior of the average canopy height, the maximum plant height, but also the culture media height and volume. Projected plant area in depth data by RANSAC (random sample consensus) segmentation approach well matched the projected plant area by RGB image processing pipeline. In addition, a successful proof of concept for in situ spectral fluorescence monitoring was achieved and challenges of thermal imaging were documented. Potential use cases for the digital quantification of key performance parameters in research and commercial application are discussed. Conclusion: The technical realization of “Phenomenon” allows phenotyping of plant in vitro cultures under highly challenging conditions and enables multi-sensory monitoring through closed vessels, ensuring the aseptic status of the cultures. Automated sensor application in plant tissue culture promises great potential for a non-destructive growth analysis enhancing commercial propagation as well as enabling research with novel digital parameters recorded over time

Reduksjon av fotooksidasjon i meieriprodukter med skreddersydd lys barriere egenskaper i emballasje

Photooxidation is one of the major causes of food quality deterioration. Packaging is a common tool to protect against light and consequently prolong the shelf life of food. Transparent packaging materials are being widely used in the food industry so that the consumers can see the product prior to purchase. It is therefore a challenge to come up with innovative transparent packaging solutions that still have optimal light barrier properties. The aim of this thesis was to study the effect of different wavelengths of light and storage conditions on photooxidation in dairy products. The knowledge obtained from these photooxidation studies was then used to design appropriate light barrier packaging materials for preventing photooxidation in dairy products. Descriptive sensory evaluation has been the main method for measuring photooxidation in this study since it is sensitive and relevant. Fluorescence spectroscopy has been an important tool for studying and understanding the photobleaching going on in dairy products. The method allows monitoring of the photodegradation of the photosensitizers during light exposure, and can help to understand differences caused by different wavelengths of exposure light. Singlet Oxygen Sensor Green® (SOSG) reagent was applied for the first time in a food study. It was used to measure the amount of singlet oxygen formed in photooxidation Type II reaction. In these studies, we have observed that long wavelengths (> 550 nm) in the visible region (orange light) tended to give more photooxidation in milk than did shorter wavelengths (< 500 nm) of blue light. The photooxidation from light above 550 nm was most likely due to the naturally occurring photosensitizers chlorophyll and protoporphyrin IX which absorb light in this region. Additionally, β-carotene will probably act as an optical filter in the blue region (< 500 nm) reducing the amount of light to react with the photosensitizers absorbing in this region (riboflavin, chlorophyll and protoporphyrin IX). It was also documented that with regard to photooxidation there was an interaction effect between wavelength of light and the storage atmosphere. Wavelengths in the red region resulted in stronger photooxidation in low oxygen atmosphere, whereas blue light gave stronger phtooxidation in high oxygen atmosphere. This indicates that different photooxidation pathways are active for different wavelengths. In a study on cheese, it was shown that longer wavelengths also penetrated deeper into the food matrix, generating off-flavors further into the cheese than shorter wavelengths. This might also explain why longer wavelengths resulted in more photooxidation, and it also illustrated the importance of proper sampling with regard to studies of photooxidation. New transparent materials with tailor made light barrier were developed by using different pigments and additives and combinations of them. All films had a shade of green and transmitted light in the green region to avoid the main absorption areas of known photosensitizers in the blue and red regions. The best protection of photooxidation in pasteurized milk was obtained by blocking wavelengths below 450 nm and also minimizing light at wavelengths longer than 600 nm. The approach of first elucidating the photooxidation properties and then, based on this, design optimized packaging materials is a general methodology that can be used for other food products in the future.Lys-indusert oksidasjon er en av de viktigste årsakene til kvalitetsforringelse av mat. Emballasje er vanlig å bruke for å beskytte mot lys og dermed forlenge holdbarheten av matvarer. Transparente emballasje er mye brukt i næringsmiddelindustrien slik at forbrukerne kan se produktet før kjøp. Det er dermed en utfordring å komme opp med innovative, gjennomsiktig emballasjeløsninger som allikevel har optimale lysbarriereegenskaper. Målet med denne avhandlingen var å studere effekten av ulike bølgelengder av lys og lagringsbetingelser på fotooksidasjon i meieriprodukter. Resultatene fra disse forsøkene ble så benyttet som basis for å utforme emballasjematerialer med lysbarrierer for å hindre fotooksidasjon. Sensorisk evaluering var hovedmetoden for å måle graden av fotooksidasjon under ulike lagringsforhold fordi den er sensitiv og relevant. Fluorescensspektroskopi har vært et viktig verktøy for å studere lysets innvirkning på meieriprodukter. Metoden gjør det mulig å studere nedbrytningen av fotosensitisere i produkter utsatt for lys og kan gjøre det lettere å forstå forskjeller son skyldes ulike bølgelengder av lys. Singlet oxygen sensor green® (SOSG) reagens ble for første gang brukt i forsøk med matvarer. Reagenset ble brukt til å måle hvor mye singlet oksygen som ble dannet i fotoreaksjon Type II. Vi observerte at lengre bølgelengder (> 550 nm, oransje lys) resulterte i høyere fotooksidasjon i melk enn kortere bølgelengder (< 500 nm, blått lys). Fotooksidasjonen fra lys over 550 nm skyldtes sannsynligvis de naturlig forekommende fotosensitiserne klorofyll og protoporfyrin IX som absorberer lys i dette området. I tillegg vil β-karoten kunne fungere som et filter i det blå området og dermed redusere mengden lys som kan reagere med fotosensitiserne i dette området (riboflavin, klorofyll, protoporphyrin IX). Det ble også dokumentert en interaksjonseffekt mellom bølgelengde og atmosfære i forbindelse med fotooksidasjonen. Bølgelengder i det røde området forårsaket mer fotooksidasjon når oksygennivået var lavt mens bølgelengder i det blå området forårsaket derimot mer fotooksidasjon når oksygennivået var høyt. Dette indikerer at fotooksidasjonen benytter forskjellige reaksjonsveier ettersom lysets bølgelengde endres. Det ble påvist i ost at lengre bølgelengder trengte lengre ned i osten og forårsaket uønsket smak lengre inn enn kortere bølgelengder. Dette kan også forklare hvorfor det ble observert mer fotooksidasjon med lengre bølgelengder og viser viktigheten av riktig prøveinnsamling i studier på fotooksidasjon. Nye gjennomsiktige materialer med skreddersydde lysbarriereegenskaper ble utviklet ved bruk av forskjellige pigmenter og tilsetningsstoffer (og kombinasjoner av disse). Alle filmene var i forskjellige nyanser av grønt for å unngå absorbsjonsområdene til kjente fotosensitisere i de blå og røde områdene. Den beste beskyttelsen av pasteurisert melk ble oppnådd ved å blokkere bølgelengder under 450 nm og minimere lys med bølgelengder over 600 nm. Denne nye tilnærmingen kan justeres for å optimalisere emballasje for andre matvarer i fremtiden. Fremgangsmåten med først å bestemme fotooksidasjonsegenskapene og deretter, basert på dette, fremstille optimal emballasje er en generell metode som også kan bli benyttet for andre produkter.The Agricultural Food Research Foundatio