545 research outputs found
SnowWatch: A multi-modal citizen science application
No full textThe demo presents Snow Watch, a citizen science system that supports the acquisition and processing of mountain images for the purpose of extracting snow information, predicting the amount of water available in the dry season, and supporting a multi-objective lake regulation problem. We discuss how the proposed architecture has been rapidly prototyped using a general-purpose architecture to collect sensor and user-generated Web content from heterogeneous sources, process it for knowledge extraction, relying on the contribution of voluntary crowds, engaged and retained with gamification techniques
A framework for outdoor mobile augmented reality and its application to mountain peak detection
No full textOutdoor augmented reality applications project information of interest onto views of the world in real-time. Their core challenge is recognizing the meaningful objects present in the current view and retrieving and overlaying pertinent information onto such objects. In this paper we report on the development of a framework for mobile outdoor augmented reality application, applied to the overlay of peak information onto views of mountain landscapes. The resulting app operates by estimating the virtual panorama visible from the viewpoint of the user, using an online Digital Terrain Model (DEM), and by matching such panorama to the actual image framed by the camera. When a good match is found, meta-data from the DEM (e.g., peak name, altitude, distance) are projected in real time onto the view. The application, besides providing a nice experience to the user, can be employed to crowdsource the collection of annotated mountain images for environmental applications
Estimating Snow Cover from Publicly Available Images
No full textIn this paper, we study the problem of estimating snow cover in mountainous regions, that is, the spatial extent of the earth surface covered by snow. We argue that publicly available visual content, in the form of user-generated photographs and image feeds from outdoor webcams, can both be leveraged as additional measurement sources, complementing existing ground, satellite, and airborne sensor data. To this end, we describe two content acquisition and processing pipelines that are tailored to such sources, addressing the specific challenges posed by each of them, e.g., identifying the mountain peaks, filtering out images taken in bad weather conditions, and handling varying illumination conditions. The final outcome is summarized in a snow cover index, which indicates for a specific mountain and day of the year the fraction of visible area covered by snow, possibly at different elevations. We created a manually labeled dataset to assess the accuracy of the image snow covered area estimation, achieving 90.0% precision at 91.1% recall. In addition, we show that seasonal trends related to air temperature are captured by the snow cover index
Compressing web Geodata for real-time environmental applications
No full textThe advent of connected mobile devices has caused an unprecedented availability of geo-referenced user-generated content, which can be exploited for environment monitoring. In particular, Augmented Reality (AR) mobile applications can be designed to enable citizens collect observations, by overlaying relevant meta-data on their current view. This class of applications rely on multiple meta-data, which must be properly compressed for transmission and real-time usage. This paper presents a two-stage approach for the compression of Digital Elevation Model (DEM) data and geographic entities for a mountain environment monitoring mobile AR application. The proposed method is generic and could be applied to other types of geographical data
Multimedia on the Mountaintop: Using public snow images to improve water systems operation
No full textThis paper merges multimedia and environmental research to verify the utility of public web images for improving water management in periods of water scarcity, an increasingly critical event due to climate change. A multimedia processing pipeline fetches mountain images from multiple sources and extracts virtual snow indexes correlated to the amount of water accumulated in the snow pack. Such indexes are used to predict water availability and design the operating policy of Lake Como, Italy. The performance of this informed policy is contrasted, via simulation, with the current operation, which depends only on lake water level and day of the year, and with a policy that exploits official Snow Water Equivalent (SWE) estimated from ground stations data and satellite imagery. Virtual snow indexes allow improving the system performance by 11.6% w.r.t. The baseline operation, and yield further improvement when coupled with official SWE information, showing that the two data sources are complementary. The proposed approach exemplifies the opportunities and challenges of applying multimedia content analysis methods to complex environmental problems
Towards an unbiased approach for the evaluation of social data geolocation
No full textWe present a study that reveals a significant statistical bias in the distributions of geolocated and non-geolocated social data. We state that this bias affects the real performance of social geolocation algorithms and can impair the results of these algorithms, which are commonly trained and tested on datasets consisting of crawled geolocated data. At last, we propose the construction of an a-posteriori geolocated dataset for an unbiased estimation of new and state-of-the-art algorithms alike
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