Dragan Ahmetovic

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Independent mobility in unfamiliar environments is a significant challenge for people with severe vision impairment. Among other problems, one specific issue concerns the identification of those road signs which can be recognized by sight only. In this paper we present ZebraLocalizer, an application for mobile devices that identifies zebra crossings and(More)
—Autonomous mobility is a challenge for visually impaired people. In the last years, a number of solutions have been proposed in the scientific literature to support visually impaired people during road crossing. In our previous work we presented ZebraLocalizer a mobile application that detects zebra crossings and guides the user to safely cross. In this(More)
In this paper we propose a computer vision-based technique that mines existing spatial image databases for discovery of zebra crosswalks in urban settings. Knowing the location of crosswalks is critical for a blind person planning a trip that includes street crossing. By augmenting existing spatial databases (such as Google Maps or OpenStreetMap) with this(More)
It is well known that mathematics presents a number of hindrances to visually impaired students. In case of function graphs, for example, several assistive solutions have been proposed to enhance their accessibility. Unfortunately, both hardware tools (e.g., tactile paper) and existing software applications cannot guarantee, at the same time, a clear(More)
—Many solutions proposed in the literature to enforce privacy in presence of location information use, implicitly or explicitly , spatial granularities. However, most of the contributions do not describe the formal and computational properties of this tool in details. In this paper we propose three families of spatial granularities, specifically designed(More)
Tablet computers are becoming a common tool to support learning since primary school. Indeed, many didactic applications are already available on online stores. Most of these applications engage the child by immersing the educational purpose of the software within an entertaining environment, often in the form of a game with sophisticated graphic and(More)
In the last years several solutions were proposed to support people with visual impairments or blindness during road crossing. These solutions focus on computer vision techniques for recognizing pedestrian crosswalks and computing their relative position from the user. Instead, this contribution addresses a different problem; the design of an auditory(More)
NavCog is a novel smartphone navigation system for people with visual impairments or blindness, capable of assisting the users during autonomous mobility in complex and unfamiliar indoor/outdoor environments. The accurate localization achieved by NavCog is used for precise turn-by-turn way-finding assistance as the first step, but the ultimate goal is to(More)