Research in interactive scene analysis

Cooperative (man-machine) scene analysis techniques were developed whereby humans can provide a computer with guidance when completely automated processing is infeasible. An interactive approach promises significant near-term payoffs in analyzing various types of high volume satellite imagery, as well as vehicle-based imagery used in robot planetary exploration. This report summarizes the work accomplished over the duration of the project and describes in detail three major accomplishments: (1) the interactive design of texture classifiers; (2) a new approach for integrating the segmentation and interpretation phases of scene analysis; and (3) the application of interactive scene analysis techniques to cartography

Historical collaborative geocoding

The latest developments in digital have provided large data sets that can increasingly easily be accessed and used. These data sets often contain indirect localisation information, such as historical addresses. Historical geocoding is the process of transforming the indirect localisation information to direct localisation that can be placed on a map, which enables spatial analysis and cross-referencing. Many efficient geocoders exist for current addresses, but they do not deal with the temporal aspect and are based on a strict hierarchy (..., city, street, house number) that is hard or impossible to use with historical data. Indeed historical data are full of uncertainties (temporal aspect, semantic aspect, spatial precision, confidence in historical source, ...) that can not be resolved, as there is no way to go back in time to check. We propose an open source, open data, extensible solution for geocoding that is based on the building of gazetteers composed of geohistorical objects extracted from historical topographical maps. Once the gazetteers are available, geocoding an historical address is a matter of finding the geohistorical object in the gazetteers that is the best match to the historical address. The matching criteriae are customisable and include several dimensions (fuzzy semantic, fuzzy temporal, scale, spatial precision ...). As the goal is to facilitate historical work, we also propose web-based user interfaces that help geocode (one address or batch mode) and display over current or historical topographical maps, so that they can be checked and collaboratively edited. The system is tested on Paris city for the 19-20th centuries, shows high returns rate and is fast enough to be used interactively.Comment: WORKING PAPE

Development of a method for mapping the highest coastline in Sweden using breaklines extracted from high resolution digital elevation models

[b]Utveckling av en metod för att kartera högsta kustlinjen i Sverige med hjälp av brytlinjer extraherade från högupplösta höjdmodeller[/b] Högsta kustlinjens (HK) geografiska läge i landskapet markerar gränsen mellan subakvatiskt och supraakvatiskt avsatta sediment. Idag varierar HKs höjd över havet från några få m.ö.h. i Skåne till omkring 289 m.ö.h. i Ångermanland på grund av den glacialisostatiska landhöjningen. Högkvalitativ HK-data är av intresse bland annat vid markanvändnings- och samhällsplanering och vid rekonstruktion av historiska havsnivåer och händelser i Östersjöns havsbassäng. Den här studien har undersökt möjligheten att använda brytlinjer i terrängen, extraherade från så kallade ”land surface parameters” (LSPs) som genererats ur högupplöst höjddata, för att automatisera karteringen av HK i svallade områden i Sverige. För att uppskatta lämpliga skaldimensioner som framhäver terrängbrytlinjer av intresse för studien testades ett intervall av fönsterstorlekar för terrängparameterberäkningarna. Fyra stycken semi-automatiserade metoder för att extrahera brytlinjer baserade på markytans krökning utvecklades i ESRIs ArcGIS 10.2.2 for Desktop och tillämpades på två pilotområden i Sverige. Metoderna är uppbyggda av ett gemensamt steg där brytlinjerna extraheras och ett individuellt steg där brytlinjerna klassificeras med olika grad av automation. För att jämföra HK-kartorna genererade från de utvecklade metoderna med HK-kartor som manuellt karterats från högupplösta terrängskuggningskartor och med HK-data som idag finns tillgänglig hos Sveriges geologiska undersökning (SGU) beräknades klassificeringsnoggrannhet och höjdfel för samtliga kartor i förhållande till referensdata. Studien fann att en 22x22m fönsterstorlek var framgångsrik för att extrahera brytlinjer av markytans krökning relaterad till strandvallar och glaciala lineationer som används för att kartera HK i pilotområdena. Noggrannhetsutvärderingen indikerar att tre av de utvecklade metoderna genererar HK-kartor med högre noggrannhet än SGUs HK-data, och liknande till högre noggrannhet än HK-kartor baserade på HK-punkter manuellt karterade från högupplösta terrängskuggningskartor. Metoderna som använder en manuell klassificering av brytlinjerna visade en högre noggrannhet än metoderna som använder en automatiserad klassificering av brytlinjerna. Denna studie visar att brytlinjer av markytans krökning genererade från högupplösta höjdmodeller kan användas för att göra kartering av HK i svallade områden mer automatiserad, strukturerad och reproducerbar samtidigt som man uppnår liknande noggrannhet som vid manuell kartering baserad på terrängskuggningskartor.[b]Development of a method for mapping the highest coastline in Sweden using breaklines extracted from high resolution digital elevation models[/b] The geospatial position of the highest coastline (HCL) defines the boundary between subaquatic and supra-aquatic deposited sediments. Today the HCL is located at different elevations throughout Sweden, a few m.a.s.l. in southern Scania to around 289 m.a.s.l. at the coast of Ångermanland, due to the glacio-isostatic rebound. High quality data of the HCL is of interest e.g. in land-use and spatial planning and when reconstructing historical sea levels and events within the Baltic Sea Basin. In this study the use of land surface parameter (LSP) breakline extraction methods applied on high resolution DEMs for automating mapping of the HCL in wave washed areas in Sweden was investigated. Appropriate scale dimensions for enhancing breaklines of interest was estimated by testing a range of moving window sizes for the LSP computations. Four semi-automated mapping methods based on curvature breakline extraction was developed in ESRI’s ArcGIS 10.2.2 for Desktop and applied on two pilot areas in Sweden. The methods consist of a common breakline extraction step and individual breakline classification steps with differing grade of automation. To compare the HCL maps generated by the developed methods with HCL maps manually mapped from high resolution hillshade maps and with the current HCL data supplied by the Geological Survey of Sweden (SGU) classification accuracies and elevation errors were computed using a reference data set. A 22x22m moving window size was found successful for the extraction of curvature breaklines related to wave washed features and glacial flow lineation features used to map the HCL within the pilot areas under investigation. The accuracy assessment indicates that three of the developed methods generate HCL maps with accuracies above the current HCL data provided by SGU and accuracies similar to or above HCL maps based on manually mapped HCL data points. Higher accuracies were found for the methods using a manual classification of the extracted breaklines than for the methods using an automated classification of the extracted breaklines. This study found that, by applying curvature breakline extraction methods on high resolution DEMs, HCL mapping in wave washed areas can be made more automated, structured and reproducible while still reaching similar accuracies as manual hillshade mapping methods.[b]Mapping the highest coastline using high resolution elevation data[/b] The highest position the coastline had after the last ice age is called the highest coastline (HCL). Today the HCL is located at different elevations throughout Sweden, a few m.a.s.l. in southern Scania to around 289 m.a.s.l. at the coast of Ångermanland, due to the glacio-isostatic rebound. The glacio-isostatic rebound occurs at different rates in Sweden, depending on to what extent the ground at a location was depressed by the weight of the ice-sheet. Today the HCL can be mapped by determining the elevation of relict landforms connected to the HCL e.g. the highest beach ridge formed by wave washing action of a historical sea. High quality data of the HCL is of interest e.g. in land-use and spatial planning and when reconstructing historical sea levels and events within the Baltic Sea Basin. Using a high resolution digital elevation model (DEM), landforms connected to the HCL can be identified with high precision. Manual digital mapping using a detailed DEM can be time-demanding and therefore partly automated mapping methods using Geographical Information Systems (GIS) are of interest when working with large areas. This study investigates the possibilities to automate the mapping of the HCL by extracting information of landforms connected to the HCL from Sweden’s national high resolution DEM. The main aim of this study was to develop a structured and reproducible method for mapping the HCL while reaching similar accuracies as manual digital mapping methods and higher accuracies than the current HCL data available at the Geological Survey of Sweden (SGU). Four mapping methods with differing automation were developed using GIS. The methods consists of two main parts: part 1 where maximum and minimum curvature information of the topography is extracted from the DEM, generating curvature breaklines which describe concave and convex surfaces of landforms, and part 2 where the breaklines are classified into landforms connected to the HCL. HCL maps produced by the developed methods were compared with manually mapped HCL maps and the HCL data supplied by the SGU. Three of the developed methods were found to generate HCL maps with the desired accuracies aimed for. Higher accuracies were found for the developed methods using a manual classification of the extracted breaklines in part 2 than for the methods using an automated classification of the breaklines. This study shows that HCL mapping, in areas where wave washed landforms are dominant, can be made more automated while still reaching similar accuracies as manual digital mapping methods

Analysis of multispectral signatures and investigation of multi-aspect remote sensing techniques

Two major aspects of remote sensing with multispectral scanners (MSS) are investigated. The first, multispectral signature analysis, includes the effects on classification performance of systematic variations found in the average signals received from various ground covers as well as the prediction of these variations with theoretical models of physical processes. The foremost effects studied are those associated with the time of day airborne MSS data are collected. Six data collection runs made over the same flight line in a period of five hours are analyzed, it is found that the time span significantly affects classification performance. Variations associated with scan angle also are studied. The second major topic of discussion is multi-aspect remote sensing, a new concept in remote sensing with scanners. Here, data are collected on multiple passes by a scanner that can be tilted to scan forward of the aircraft at different angles on different passes. The use of such spatially registered data to achieve improved classification of agricultural scenes is investigated and found promising. Also considered are the possibilities of extracting from multi-aspect data, information on the condition of corn canopies and the stand characteristics of forests

Methodology and Algorithms for Pedestrian Network Construction

With the advanced capabilities of mobile devices and the success of car navigation systems, interest in pedestrian navigation systems is on the rise. A critical component of any navigation system is a map database which represents a network (e.g., road networks in car navigation systems) and supports key functionality such as map display, geocoding, and routing. Road networks, mainly due to the popularity of car navigation systems, are well defined and publicly available. However, in pedestrian navigation systems, as well as other applications including urban planning and physical activities studies, road networks do not adequately represent the paths that pedestrians usually travel. Currently, there are no techniques to automatically construct pedestrian networks, impeding research and development of applications requiring pedestrian data. This coupled with the increased demand for pedestrian networks is the prime motivation for this dissertation which is focused on development of a methodology and algorithms that can construct pedestrian networks automatically. A methodology, which involves three independent approaches, network buffering (using existing road networks), collaborative mapping (using GPS traces collected by volunteers), and image processing (using high-resolution satellite and laser imageries) was developed. Experiments were conducted to evaluate the pedestrian networks constructed by these approaches with a pedestrian network baseline as a ground truth. The results of the experiments indicate that these three approaches, while differing in complexity and outcome, are viable for automatically constructing pedestrian networks

EXTRACTION of DEMS and ORTHOIMAGES from ARCHIVE AERIAL IMAGERY to SUPPORT PROJECT PLANNING in CIVIL ENGINEERING

Archive aerial photos represent a valuable heritage to provide information about land content and topography in the past years. Today, the availability of low-cost and open-source solutions for photogrammetric processing of close-range and drone images offers the chance to provide outputs such as DEM's and orthoimages in easy way. This paper is aimed at demonstrating somehow and to which level of accuracy digitized archive aerial photos may be used within a such kind of low-cost software (Agisoft Photoscan Professional®) to generate photogrammetric outputs. Different steps of the photogrammetric processing workflow are presented and discussed. The main conclusion is that this procedure may come to provide some final products, which however do not feature the high accuracy and resolution that may be obtained using high-end photogrammetric software packages specifically designed for aerial survey projects. In the last part a case study is presented about the use of four-epoch archive of aerial images to analyze the area where a tunnel has to be excavated

A High-Resolution Airborne Color-Infrared Camera Water Mask for the NASA ABoVE Campaign

The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July and August 2017 as part of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced from high-resolution (1 m), co-registered AirSWOT CIR imagery using a semi-automated, object-based water classification. The imagery and resulting high-resolution water masks are available as open-access datasets and support interpretation of AirSWOT radar and other coincident ABoVE image products, including LVIS, UAVSAR, AIRMOSS, AVIRIS-NG, and CFIS. These synergies offer promising potential for multi-sensor analysis of Arctic-Boreal surface water bodies. In total, 3167 km2 of open surface water were mapped from 23,380 km2 of flight lines spanning 23 degrees of latitude and broad environmental gradients. Detected water body sizes range from 0.00004 km2 (40 m2) to 15 km2. Power-law extrapolations are commonly used to estimate the abundance of small lakes from coarser resolution imagery, and our mapped water bodies followed power-law distributions, but only for water bodies greater than 0.34 (±0.13) km2 in area. For water bodies exceeding this size threshold, the coefficients of power-law fits vary for different Arctic-Boreal physiographic terrains (wetland, prairie pothole, lowland river valley, thermokarst, and Canadian Shield). Thus, direct mapping using high-resolution imagery remains the most accurate way to estimate the abundance of small surface water bodies. We conclude that empirical scaling relationships, useful for estimating total trace gas exchange and aquatic habitats on Arctic-Boreal landscapes, are uniquely enabled by high-resolution AirSWOT-like mappings and automated detection methods such as those developed here

Shoreline Evolution: Prince George County, Virginia Upper Chippokes Creek, James and Appomattox River Shorelines

Prince George County is situated between on the James River between Upper Chippokes Creek and the Appomattox Rivers (Figure 1). Because the County’s shoreline is continually changing, determining where the shoreline was in the past, how far and how fast it is moving, and what factors drive shoreline change will help define where the shoreline will be going in the future. These rates and patterns of shore change along Chesapeake Bay’s estuarine shores will differ through time as winds, waves, tides and currents shape and modify coastlines by eroding, transporting and depositing sediments. The purpose of this report is to document how the shore zone of Prince George County has evolved since 1937. Aerial imagery was taken for most of the Bay region beginning that year and can be used to assess the geomorphic nature of shore change. Aerial photos show how the coast has changed, how beaches, dunes, bars, and spits have grown or decayed, how barriers have breached, how inlets have changed course, and how one shore type has displaced another or has not changed at all. Shore change is a natural process but, quite often, the impacts of man, through shore hardening or inlet stabilization, come to dominate a given shore reach. In addition to documenting historical shorelines, the change in shore positions along the larger creeks in Prince George County will be quantified in this report. The shorelines of very irregular coasts, small creeks and around inlets, and other complicated areas will be shown but not quantified