503 research outputs found

    Removing the texture feature response to object boundaries

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    Texture is a spatial property and thus any features used to describe it must be calculated within a neighbourhood. This process of integrating information over a neighbourhood leads to what we will refer to as the texture boundary response problem, where an unwanted response is observed at object boundaries. This response is due to features being extracted from a mixture of textures and/or an intensity edge between objects. If segmentation is performed using these raw features this will lead to the generation of unwanted classes along object boundaries. To overcome this, post processing of feature images must be performed to remove this response before a classification algorithm can be applied. To date this problem has received little attention with no evaluation of the alternative solutions available in the literature of which we are aware. In this work we perform an evaluation of known solutions to the boundary response problem and discover separable median filtering to be the curre nt best choice. An in depth evaluation of the separable median filtering approach shows that it fails to remove certain parts or types of object boundary response. To overcome this failing we propose two alternative techniques which involve either post processing of the separable median filtered result or an alternative filtering technique

    Preliminary Results of a Spatial Analysis of Dublin City’s Bike Rental Scheme

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    We present some initial observations on the usage and flow patterns of the DublinBikes (DB) bicycle rental scheme across Dublin city. In September 2009 Dublin City in conjunction with outdoor advertising company JC Decaux made 450 bicycles publicly available from 40 locations around the city in a scheme called DublinBikes (DB). Cycling, as a commuting mode forms an important part of the Irish Government's Transport policy for Ireland up to 2020 stating that "a culture of cycling will be developed by 2020 to envisage around 160,000 people cycling for their daily commute, up from 35,000 in 2006"(DOT, 2009). We follow Froehlich et al (2008) who find usage patterns from these bike rental schemes can "infer cultural and geographical aspects of the city and predict future bike station usage behaviour" when combined with geographical information and local knowledge. Data captured on DB and presented in this paper covers the period of September 20th 2009 to February 15th 2010 inclusive

    Complementary texture and intensity gradient estimation and fusion for watershed segmentation

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    In this paper, we identify two current challenges associated with watershed segmentation algorithms which attempt to fuse the visual cues of texture and intensity. The first challenge is that most existing techniques use a competing gradient set which does not allow boundaries to be defined in terms of both visual cues. The second challenge is that these techniques fail to account for the spatial uncertainty inherent in texture gradients. We present a watershed segmentation algorithm which provides a suitable solution to both these challenges and minimises the spatial uncertainty in boundary localisation. This is achieved by a novel fusion algorithm which uses morphological dilation to integrate intensity and texture gradients.Aquantitative and qualitative evaluation of results is provided demonstrating that our algorithm outperforms three existing watershed algorithms

    Evaluating Twitter for Use in Environmental Awareness Campaigns

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    Many studies have shown that the effective harnessing of ICTs is critical in local, national, and global efforts to adapt and mitigate the effects of climate change. Citizens must be provided with accurate information about environmental issues and should receive this through the most effective communication channels available. In this paper we describe work in progress in evaluating Twitter as a means of distributing environmental information to citizens. This work will attempt to measure how effective the Twitter medium can be in environmental awareness campaigns for issues such as climate change by carrying out an analysis of a regularly updated database of Twitter messages. This work will also look to establish if users are environmental issues through their Twitter networks

    Preliminary Results of a Spatial Analysis of Dublin City’s Bike Rental Scheme

    Get PDF
    We present some initial observations on the usage and flow patterns of the DublinBikes (DB) bicycle rental scheme across Dublin city. In September 2009 Dublin City in conjunction with outdoor advertising company JC Decaux made 450 bicycles publicly available from 40 locations around the city in a scheme called DublinBikes (DB). Cycling, as a commuting mode forms an important part of the Irish Government's Transport policy for Ireland up to 2020 stating that "a culture of cycling will be developed by 2020 to envisage around 160,000 people cycling for their daily commute, up from 35,000 in 2006"(DOT, 2009). We follow Froehlich et al (2008) who find usage patterns from these bike rental schemes can "infer cultural and geographical aspects of the city and predict future bike station usage behaviour" when combined with geographical information and local knowledge. Data captured on DB and presented in this paper covers the period of September 20th 2009 to February 15th 2010 inclusive

    Effective Vector Data Transmission and Visualization Using HTML5

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    In this paper we evaluate the potential of the next major revision of HTML (Hypertext Markup Language), that is HTML5, to provide an effective platform for the transmission and visualization of vector based geographical data. Relative to the current version of HTML, HTML 4.01, HTML5 offers an improved platform to perform these tasks through greater interoperability with existing technologies and the introduction of many new API’s. Visualization of vector data can be achieved using the new methods of inline-SVG and the Canvas API. An analysis of the pros and cons of each method is presented. HTML5 introduces a novel WebSocket API which defines a full-duplex communication channel between client and server. This provides improved data communication both in terms of bandwidth utilization and network latency relative to existing push technologies. To demonstrate the effectiveness of HTML5 for vector data delivery a novel selective progressive transmission methodology is implemented using the WebSocket and Canvas API’s
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