User-assisted intrinsic images

For many computational photography applications, the lighting and materials in the scene are critical pieces of information. We seek to obtain intrinsic images, which decompose a photo into the product of an illumination component that represents lighting effects and a reflectance component that is the color of the observed material. This is an under-constrained problem and automatic methods are challenged by complex natural images. We describe a new approach that enables users to guide an optimization with simple indications such as regions of constant reflectance or illumination. Based on a simple assumption on local reflectance distributions, we derive a new propagation energy that enables a closed form solution using linear least-squares. We achieve fast performance by introducing a novel downsampling that preserves local color distributions. We demonstrate intrinsic image decomposition on a variety of images and show applications.National Science Foundation (U.S.) (NSF CAREER award 0447561)Institut national de recherche en informatique et en automatique (France) (Associate Research Team “Flexible Rendering”)Microsoft Research (New Faculty Fellowship)Alfred P. Sloan Foundation (Research Fellowship)Quanta Computer, Inc. (MIT-Quanta T Party

Visualization for exploratory analysis of spatio-temporal data

Analysis of spatio-temporal data has become critical with the emerge of ubiquitous location sensor technologies and applications keeping track of such data. Especially with the widespread availability of low cost GPS devices, it is possible to record data about the location of people and objects at a large scale. Data visualization plays a key role in the successful analysis of these kind of data. Due to the complex nature of this analysis process, current approaches and analytical tools fail to help spatio-temporal thinking and they are not effective when solving large range of problems. In this work, we propose an interactive visualization tool to support human analyst understand user behaviors by analyzing location patterns and anomalies in massive collections of spatio-temporal data. The tool that we developed within this work combines a geovisualization framework with 3D visualizations and histograms. Tool's effectiveness in exploratory analysis is tested by trend analysis and anomaly detection in a real mobile service dataset with almost 1.5 million rows

An evaluation of partial differential equations based digital inpainting algorithms

Partial Differential equations (PDEs) have been used to model various phenomena/tasks in different scientific and engineering endeavours. This thesis is devoted to modelling image inpainting by numerical implementations of certain PDEs. The main objectives of image inpainting include reconstructing damaged parts and filling-in regions in which data/colour information are missing. Different automatic and semi-automatic approaches to image inpainting have been developed including PDE-based, texture synthesis-based, exemplar-based, and hybrid approaches. Various challenges remain unresolved in reconstructing large size missing regions and/or missing areas with highly textured surroundings. Our main aim is to address such challenges by developing new advanced schemes with particular focus on using PDEs of different orders to preserve continuity of textural and geometric information in the surrounding of missing regions. We first investigated the problem of partial colour restoration in an image region whose greyscale channel is intact. A PDE-based solution is known that is modelled as minimising total variation of gradients in the different colour channels. We extend the applicability of this model to partial inpainting in other 3-channels colour spaces (such as RGB where information is missing in any of the two colours), simply by exploiting the known linear/affine relationships between different colouring models in the derivation of a modified PDE solution obtained by using the Euler-Lagrange minimisation of the corresponding gradient Total Variation (TV). We also developed two TV models on the relations between greyscale and colour channels using the Laplacian operator and the directional derivatives of gradients. The corresponding Euler-Lagrange minimisation yields two new PDEs of different orders for partial colourisation. We implemented these solutions in both spatial and frequency domains. We measure the success of these models by evaluating known image quality measures in inpainted regions for sufficiently large datasets and scenarios. The results reveal that our schemes compare well with existing algorithms, but inpainting large regions remains a challenge. Secondly, we investigate the Total Inpainting (TI) problem where all colour channels are missing in an image region. Reviewing and implementing existing PDE-based total inpainting methods reveal that high order PDEs, applied to each colour channel separately, perform well but are influenced by the size of the region and the quantity of texture surrounding it. Here we developed a TI scheme that benefits from our partial inpainting approach and apply two PDE methods to recover the missing regions in the image. First, we extract the (Y, Cb, Cr) of the image outside the missing region, apply the above PDE methods for reconstructing the missing regions in the luminance channel (Y), and then use the colourisation method to recover the missing (Cb, Cr) colours in the region. We shall demonstrate that compared to existing TI algorithms, our proposed method (using 2 PDE methods) performs well when tested on large datasets of natural and face images. Furthermore, this helps understanding of the impact of the texture in the surrounding areas on inpainting and opens new research directions. Thirdly, we investigate existing Exemplar-Based Inpainting (EBI) methods that do not use PDEs but simultaneously propagate the texture and structure into the missing region by finding similar patches within the rest of image and copying them into the boundary of the missing region. The order of patch propagation is determined by a priority function, and the similarity is determined by matching criteria. We shall exploit recently emerging Topological Data Analysis (TDA) tools to create innovative EBI schemes, referred to as TEBI. TDA studies shapes of data/objects to quantify image texture in terms of connectivity and closeness properties of certain data landmarks. Such quantifications help determine the appropriate size of patch propagation and will be used to modify the patch propagation priority function using the geometrical properties of curvature of isophotes, and to improve the matching criteria of patches by calculating the correlation coefficients from the spatial, gradient and Laplacian domains. The performance of this TEBI method will be tested by applying it to natural dataset images, resulting in improved inpainting when compared with other EBI methods. Fourthly, the recent hybrid-based inpainting techniques are reviewed and a number of highly performing innovative hybrid techniques that combine the use of high order PDE methods with the TEBI method for the simultaneous rebuilding of the missing texture and structure regions in an image are proposed. Such a hybrid scheme first decomposes the image into texture and structure components, and then the missing regions in these components are recovered by TEBI and PDE based methods respectively. The performance of our hybrid schemes will be compared with two existing hybrid algorithms. Fifthly, we turn our attention to inpainting large missing regions, and develop an innovative inpainting scheme that uses the concept of seam carving to reduce this problem to that of inpainting a smaller size missing region that can be dealt with efficiently using the inpainting schemes developed above. Seam carving resizes images based on content-awareness of the image for both reduction and expansion without affecting those image regions that have rich information. The missing region of the seam-carved version will be recovered by the TEBI method, original image size is restored by adding the removed seams and the missing parts of the added seams are then repaired using a high order PDE inpainting scheme. The benefits of this approach in dealing with large missing regions are demonstrated. The extensive performance testing of the developed inpainting methods shows that these methods significantly outperform existing inpainting methods for such a challenging task. However, the performance is still not acceptable in recovering large missing regions in high texture and structure images, and hence we shall identify remaining challenges to be investigated in the future. We shall also extend our work by investigating recently developed deep learning based image/video colourisation, with the aim of overcoming its limitations and shortcoming. Finally, we should also describe our on-going research into using TDA to detect recently growing serious “malicious” use of inpainting to create Fake images/videos

Web-based Stereoscopic Collaboration for Medical Visualization

Medizinische Volumenvisualisierung ist ein wertvolles Werkzeug zur Betrachtung von Volumen- daten in der medizinischen Praxis und Lehre. Eine interaktive, stereoskopische und kollaborative Darstellung in Echtzeit ist notwendig, um die Daten vollständig und im Detail verstehen zu können. Solche Visualisierung von hochauflösenden Daten ist jedoch wegen hoher Hardware- Anforderungen fast nur an speziellen Visualisierungssystemen möglich. Remote-Visualisierung wird verwendet, um solche Visualisierung peripher nutzen zu können. Dies benötigt jedoch fast immer komplexe Software-Deployments, wodurch eine universelle ad-hoc Nutzbarkeit erschwert wird. Aus diesem Sachverhalt ergibt sich folgende Hypothese: Ein hoch performantes Remote- Visualisierungssystem, welches für Stereoskopie und einfache Benutzbarkeit spezialisiert ist, kann für interaktive, stereoskopische und kollaborative medizinische Volumenvisualisierung genutzt werden. Die neueste Literatur über Remote-Visualisierung beschreibt Anwendungen, welche nur reine Webbrowser benötigen. Allerdings wird bei diesen kein besonderer Schwerpunkt auf die perfor- mante Nutzbarkeit von jedem Teilnehmer gesetzt, noch die notwendige Funktion bereitgestellt, um mehrere stereoskopische Präsentationssysteme zu bedienen. Durch die Bekanntheit von Web- browsern, deren einfach Nutzbarkeit und weite Verbreitung hat sich folgende spezifische Frage ergeben: Können wir ein System entwickeln, welches alle Aspekte unterstützt, aber nur einen reinen Webbrowser ohne zusätzliche Software als Client benötigt? Ein Proof of Concept wurde durchgeführt um die Hypothese zu verifizieren. Dazu gehörte eine Prototyp-Entwicklung, deren praktische Anwendung, deren Performanzmessung und -vergleich. Der resultierende Prototyp (CoWebViz) ist eines der ersten Webbrowser basierten Systeme, welches flüssige und interaktive Remote-Visualisierung in Realzeit und ohne zusätzliche Soft- ware ermöglicht. Tests und Vergleiche zeigen, dass der Ansatz eine bessere Performanz hat als andere ähnliche getestete Systeme. Die simultane Nutzung verschiedener stereoskopischer Präsen- tationssysteme mit so einem einfachen Remote-Visualisierungssystem ist zur Zeit einzigartig. Die Nutzung für die normalerweise sehr ressourcen-intensive stereoskopische und kollaborative Anatomieausbildung, gemeinsam mit interkontinentalen Teilnehmern, zeigt die Machbarkeit und den vereinfachenden Charakter des Ansatzes. Die Machbarkeit des Ansatzes wurde auch durch die erfolgreiche Nutzung für andere Anwendungsfälle gezeigt, wie z.B. im Grid-computing und in der Chirurgie

Kahden muuttujan sävyjen sekoitus – väriasteikoiden suunnittelu kahden muuttujan koropleettikartoille räätälöidyllä työkalulla

Bivariate maps are a type of map visualization where two related data series are displayed at once for each data point. They can answer questions of how two variables interrelate in a geographical context using several kinds of encodings — visual variables — such as shape or color. The most common types are choropleth maps that use color hue and lightness to encode data and symbol-based maps that use shape size for both data series. Bivariate maps have seen a minor surge in popularity with new software tools but remain an understudied visualization type with a lack of clear usage recommendations. The thesis consists of a theoretical and a practical part. The purpose was to collate existing recommendations about the design of bivariate maps and determine whether they are considered a useful type of visualization. The theoretical part was a literature survey of relevant visualization and cartography literature, including empirical studies. I also sought to see whether bivariate choropleths are considered more effective than other types. The practical part was building a web tool prototype for bivariate color scale creation limited to choropleth maps, the Bivariate hue blender. The tool uses the Hue-Chroma-Lightness (HCL) color space for scheme design. By rotating the hue angle of an input color by a user-defined amount, a new color can be created. Intermediate colors are generated by blending these two with each other and a light secondary input color. The primary purpose of the tool was to improve color scheme creation and the building process used the framework of research-based design. It involved building the tool, using it to evaluate seven existing palettes, and creating three new palettes. These were applied to four different bivariate maps using statistical data from Finland in two different geographical divisions. Test data was selected using contingency table visualizations to ensure that all classes contain values. In addition to the color scales, a bivariate ordinal texture design was created. Bivariate maps were found to be grouped in categories using the concept of integral and separable dimensions. Bivariate choropleth maps were found to be a relevant visualization type, provided that the data is suitable, and that the number of classes is no larger than 9. An issue pertaining to color contrast was identified — accessibility guidelines stipulate a lightness difference between adjacent hues that require the use of strokes in most choropleth maps. Questions concerning effectiveness of other types, how bivariate symbols interact and how viewers can use bivariate maps for analytical tasks remain unresolved. The tool was subjectively found to enable better control over bivariate color scale creation than other similar software. The evaluated bivariate palettes had issues in lightness uniformity and separation of colors, which could be resolved in the three new palettes. These were found to be at least as practical as the seven initial palettes. This work has concluded that bivariate maps can be considered useful in special cases with the right data, which should encourage visualization designers to employ them. It has contributed a prototype tool that aids the creation of new perceptually uniform color scales for bivariate choropleth maps. Three new colorblind-safe 3×3 palettes are an addition to the limited set of schemes in active use. The method of selecting data using contingency tables can aid in creating bivariate maps.Kahden muuttujan tietokartat ovat visualisointityyppi, jossa kaksi toisiinsa liittyvää tietosarjaa näytetään kunkin datapisteen kohdalla. Niillä voidaan tutkia kuinka kaksi muuttujaa ovat yhteydessä toisiinsa maantieteellisessä kontekstissa, käyttämällä useita erilaisia visuaalisia muuttujia – kuten muotoa tai väriä. Yleisimpiä tyyppejä ovat koropleettikartat, joissa käytetään värin sävyä ja vaaleutta tietojen esittämiseen, sekä symbolikartat, joissa käytetään muodon kokoa molemmille datasarjoille. Kahden muuttujan karttojen suosio on kasvanut uusien ohjelmistotyökalujen myötä, mutta ne ovat edelleen vähän tutkittu visualisointityyppi, josta puuttuvat selkeät käyttösuositukset. Opinnäytetyöni koostuu teoreettisesta ja käytännön osasta. Tarkoituksena on ollut koota olemassa olevia suosituksia kahden muuttujan kartoista ja selvittää, pidetäänkö niitä hyödyllisenä visualisointityyppinä. Teoriaosuus on kirjallisuuskatsaus visualisointi- ja kartografiakirjallisuuteen, mukaan luettuna myös empiiriset tutkimukset. Pyrin myös selvittämään, pidetäänkö kahden muuttujan koropleettikarttoja tehokkaampina kuin muita kahden muuttujan karttatyyppejä. Käytännön osuus on verkkotyökalun prototyyppi, Bivariate hue blender, joka on tehty kahden muuttujan väriasteikkojen luomista varten. Työkalu käyttää Hue-Chroma-Lightness (HCL; sävy, kromaattisuus, vaaleus) -väriavaruutta. Kun syötetyn värin sävykulmaa kääntää, syntyy uusi väri. Alkuperäisestä ja uudesta väristä luodaan kaksi erillistä väriasteikkoa vaaleasta aloitussävystä ja näitä yhdistämällä muodostetaan asteikon välivärit. Työkalun ensisijaisena tarkoituksena on ollut helpottaa väriasteikkojen luomista. Sen kehittämisessä on sovellettu tutkimukseen perustuvaa suunnittelua. Työkalun avulla on arvioitu seitsemän palettia ja luotu kolme uutta. Näitä on sovellettu neljään erilaiseen kahden muuttujan karttaan, joissa on käytetty tilastotietoja Suomesta kahden eri maantieteellisen jaon mukaan. Väriasteikkojen lisäksi on luotu kuviotekstuuri. Tutkimuksessa todetaan, että kahden muuttujan kartat voidaan jakaa luokkiin käyttäen kokonaisten ja eroteltavien ulottuvuuksien käsitettä. Koropleettikarttojen todetaan olevan toimiva laji, kunhan aineisto on sopiva ja luokkia enintään yhdeksän. Työssä tunnistettiin värikontrastiin liittyvä ongelma – esteettömyysohjeissa määrätyt vierekkäisten sävyjen vaaleuserot edellyttävät ääriviivojen käyttöä useimmissa kartoissa. Tutkimuksessa auki jäävät kysymykset koskevat muiden tyyppien tehokkuutta, kaksimuuttujaisten symbolien vuorovaikutusta ja sitä, kuinka katsoja lukee ja käyttää näitä karttoja. Työkalun voidaan todeta subjektiivisesti mahdollistavan paremman hallinnan kaksimuuttujaväriasteikkojen luomisessa vastaaviin ohjelmiin verrattuna. Arvioiduissa paleteissa oli ongelmia vaaleuden tasaisuudessa ja värien erottelussa, jotka nyt voitiin ratkaista kolmessa uudessa paletissa. Näiden todetaan olevan ainakin yhtä käytännöllisiä kuin seitsemän alkuperäistä palettia. Työn loppupäätelmä on, että kaksimuuttujaisia karttoja voidaan pitää hyödyllisinä tietyissä tapauksissa ja niihin soveltuvalla datalla, mikä voi kannustaa visualisointisuunnittelijoita käyttämään niitä. Työn tuloksena on prototyyppityökalu, joka auttaa luomaan uusia tasajakoisia väriskaaloja kahden muuttujan koropleettikarttoja varten. Kolme uutta palettia on lisäys aktiivisessa käytössä olevien kaksimuuttujaisten palettien rajalliseen joukkoon. Kontingenssitaulukoihin perustuva aineiston valintamenetelmä voi auttaa suunnittelijoita kahden muuttujan karttojen luomisessa

Hydrogeological and hydrochemical investigations in the Rioverde basin, Mexico

The study area is part of a 4500 km2 large sedimentary basin, the Rioverde basin, in the central-northern part of Mexico at altitudes of 1000 masl surrounded by the volcanics of the Mesa Central to the east and the Sierra Madre Occidental to the west. Average annual temperatures in the basin are approximately 21°C, precipitation is about 500 mm/a. Typical for a semiaride climate rainfall occurs in few, heavy rain events during the rainy season around September while in other months, especially February and March there may be no rainfall at all. Potential evaporation with about 1600 mm/a exceeds precipitation by far. The biggest town, Rioverde, is located in the southern part of the basin, on the southern riverside of the river rio verde, that crosses the basin from the west to the east. Westsouthwest of the town Rioverde the area around the village El Refugio is intensively used for irrigation agriculture. The irrigation water is provided by a karst spring with a yield of about 4.35 m3/s, the Media Luna, and approximately 600 wells, about 10 of them garantueeing also Rioverde´s drinking water supply. North of Rioverde around the village of Pastora agriculture is limited especially due to soil properties and water quality, drinking water is supplied by tanks. The whole eastern part of the basin is sparsely populated wasteland. The most important structure for the geological development in this area and the deposition of the corresponding rocks is the platform Valles - San Luis Potosi that formed during the Appalachian (Permian-Triassic) and remained emerged during the entire Triassic and Jurassic. At the beginning of Cretaceous the platform subsided and the oldest sediments that can be found at the basin´s margins and underneath the Quarternary basin fill in the basin are Cretaceous limestones. At the transition from Cretaceous to Tertiary compressive tectonical forces from the SW related to the subduction of the Farallon plate caused the formation of a basin and range province today bordering the basin to the north and northeast. Subsequent extension enabled acid volcanic extrusions, mainly rhyoliths, today forming the basin´s eastern border. It could be shown in this study that the sedimentary basin is a tectonical graben structure formed at the transition from Tertiary to Quarternary. The main thrust of this graben structure probably is an elongation of the Meozoic platform that was activated again. The further Quarternary development was reconstructed for the first time in this thesis. The sudden subsidence of the graben is supposed to have created a drainageless depression, filled by shallow lakes and puddles which were subject to intensive evaporation in the semiaride environment. The deposition of chalk and later on gypsum happens in this period. It is assumed that the river rio verde filled the depression rather fast with debris from the nearby Sierra creating a deltaic fan of gravel, sand and clay in the southwestern part of the basin. Later on basalts and tuffs intruded in these Quarternary sediments. The youngest deposits are caliche and travertine which were differentiated in this study. The whole depth of the Quarternary basin fill was found to be around 200 m in average, 450 m at the most. Starting with these new ideas about geology and tectonics a hydrogeological model for the southern part of the basin was set up for the first time in a serie of many previous projects. The model was based on both hydraulic parameters as the calculations of the groundwater recharge, the catchment area and the groundwater flow direction, obtained from the interpretation of time series of groundwater table determinations, and hydrogeochemical results from the field campaign in July and October 1999. Reverse geochemical modeling with PhreeqC2, done for 4 representative wells, proved the created model to be consistent. Concerning hydraulic parameters the most important results are the following: Two main aquifers exist in the basin, a confined Cretaceous and an unconfined Quarternary one both interconnected without distinct aquiclud in between. The main recharge area for the Cretaceous aquifer was proven to be the Sierra west of the basin; in the basin groundwater recharge was calculated to be very low. The calculated amount of recharged groundwater for the basin´s southwestern part equals the yield of the karst spring Media Luna (4.35 m3/s), while in the northwestern part it is only one quarter of that. The main drain in the southwestern part is the river rio verde causing a general groundwater flow for both aquifers from the west to the east, while in the northwestern part the shallow groundwater (Alluvium) flow it is from the east to the west, probably due to the influence of the graben fault zone with higher permeability. No man made declining of the groundwater table was detected in Pastora area, while severe drawdown of -10 to -15 m from 1972-1997 was documented for El Refugio. South of El Refugio, near El Jabali, several former dug wells are dry and new wells have been drilled with watertables 4-15 m below the bottom of the old dug wells. This is consistents with reports of former wetlands that are cultivated farmland nowadays and indicates drawdown of the groundwater table over a large area. For detailed chemical investigations (main ions, trace elements, isotopes, pesticides) two distinct areas were choosen, El Refugio and Pastora. Observations from previous projects were confirmed for Pastora area with high mineralization and Ca2+ and SO4 2- concentrations close to gypsum saturation resulting from the contact with Quarternary evaporites. Considering El Refugio reported low mineralization and a predominancy of Ca2+ and HCO3- could only be confirmed for the deep wells tapping Cretaceous groundwater but also Quarternary groundwater through leakage conditions or due to the fact having a screen in both Quarternary and Cretaceous aquifer. Shallow wells in El Refugio show the influence of Quarternary evaporites, yet not as high as in Pastora. The system of karst springs with the biggest karst spring, Media Luna, it´s smaller neighbour Anteojitos (0.25 m3/s) and Ojo de Agua de Solano, the spring of the river rio verde, are characterized by increased concentrations of Ca2+ and SO4 2- supposed to result from the contact to a Cretaceous gypsum formation (Guaxcama) at the bottom of the Cretaceous limestone. The idea that the 6 different outlets from the karst spring Media Luna spill water from different horizons or aquifers was disproved by direct sampling of the outlets by scuba diving. The reported high arsenic concentrations of 1-5 mg/L that originally were the main point of concern fortunately were neither confirmed in the above described wells and springs nor in about 30 further wells spread all over the southern part of the basin. A new method for determining both total arsenic and As(III) directly on-site was tested and though some handicaps like handling, reaction time and calibration, especially for speciation, still have to be improved, the equipment was proved to work in general. Comparison with laboratory HGAAS showed a maximum negative deviation of -5.6 mg/L and a maximum positive deviation of +2.2 mg/L. Increased pesticide concentrations, especially DDT (2-6 mg/L) as well as a, b, g-HCH (0.08-1.1 mg/L), heptachlor (0.02-0.2 mg/L), dieldrin (0.03-0.4 mg/L), aldrin (0.05-1 mg/L) and endrin (0.06-0.3 mg/L), in all of Rioverde´s drinking water wells, except for the youngest well San Diego drilled in 1999, remain the most severe concern from the chemical part of this study. The presentation of the geological and hydrogeological results (mapping part of this thesis) was not done in the traditional way of printed maps, but as multi-layer digital atlas (supplied on a 650 MB CD) containing the vector objects geology (basis information taken from existing geological maps, checked at about 85 outcrops and modified), tectonics and watersheds/flowpaths, the raster objects digital elevation model (DEM), various false color Landsat images, soil classes and potential land use maps and a contour map with the depth of the Quarternary basin fill as well as numerous databases about the geological outcrops, drillings, geophysics, rock samples, meteorological stations, river flow gauges, groundwater tables from 1972-1999, pumping tests, hydrogeochemical results from July and October 1999 and arsenic concentrations in the whole southern part of the basin. Additionally detailed description for all the wells and springs sampled during the field campaign was performed collecting information about the location, environment and use of the wells, well depth, yield and construction, well equipment, operation, time series of groundwater tables and previous hydrogeochemical analysis.researc

Effects of Complementary use of Organic and Inorganic fertilizers on the growth and yield of Cucumber (Cucumu sativus. L.) on an ultisol

A field study was conducted in 2008 and 2009 early cropping seasons to assess the response of cucumber (Cucumus sativus L.) to complementary use of organic and inorganic fertilizers in Uyo agro-ecology. The fertilizer treatments were: NPK (15:15:15) at 100 and 200 kgha-1, poultry manure (PM) at 5 and 10 tha-1 , and complementary application of 100 kgha-1 of NPK + 5 tha-1 of PM, 100 kgha-1 of NPK + 10 tha-1 of PM, 200 kgha1 of NPK +5 tha-1 of PM ,200 kgha-1 of NPK +10 tha-1 of PM and control (no fertilizer). Results showed significant differences (P<0.05) in all the growth and yield parameters considered in both cropping seasons. The combined application of 200 kgha-1 of NPK and 10 tha-1 of PM performed better than sole application of either organic or inorganic fertilizer, with fresh fruit yield of 14.63 and 14.92 tha-1 in 2008 and 2009, respectively and exceeded other treatments by 1 -76% and 1-73% in 2009 and 2010, respectively. This indicates strongly the synergistic benefits of using both organic and inorganic fertilizers even at lower rates