In this review paper, a qualitative comparison of the performance of nine different segmentation algorithms on a data base of infrared images of vehicles is described. The segmentation methods are categorised accordin...
详细信息
In this review paper, a qualitative comparison of the performance of nine different segmentation algorithms on a data base of infrared images of vehicles is described. The segmentation methods are categorised according to their mode of operation into three distinct generic classes of algorithm: namely ‘grey level threshold techniques’, ‘three dimensional histogram methods’ and ‘pixel classification techniques’. Each segmentation technique is guided to a subset of the image by a spoke filter detection algorithm which locates regions of the scene that most resemble blob shaped man-made objects. A short list of four segmentation algorithms is compiled, of which two methods from the ‘pixel classification’ class, aK-nearest neighbour (KNN) and a Bayesian algorithm, are selected. The final preference is for the Bayesian technique, the KNN method being less favoured owing to the higher computational burden.
We distinguish between the roles played by spatial attention and conscious intention in terms of their impact on the processing of segmentation signals, like discontinuities in lines, associated with the act of scruti...
详细信息
We distinguish between the roles played by spatial attention and conscious intention in terms of their impact on the processing of segmentation signals, like discontinuities in lines, associated with the act of scrutinizing. We showed previously that the processing of discontinuities in lines can be activated. This is evidenced by an impairment in the detection of a gap between parallel elements when it follows a gap between collinear elements in the same location and orientation. This effect is no longer observed if attention is divided between two gaps in the first stimulus. The results from this study show that focusing attention on a gap between collinear elements is not enough to observe a modulation, consistently with the need to integrate, rather than to separate, collinear elements in usual conditions. The modulation is sensitive to the conscious expectations of subjects, suggesting that an intention can trigger modulations that spatial attention cannot. (c) 2005 Elsevier Inc. All rights reserved.
This article presents an analysis of multidimensional segregation in Stockholm. Drawing on official statistics and existing empirical research, spatial and socio-economic segregation are found to be increasingly tied ...
详细信息
This article presents an analysis of multidimensional segregation in Stockholm. Drawing on official statistics and existing empirical research, spatial and socio-economic segregation are found to be increasingly tied to ethnicity, in a global city largely divided between affluent inner-city and marginalized peripheral boroughs. The analysis finds that migration flows' impact on Stockholm's asymmetric development must be understood in a historical perspective, as particular interactions between structural constraints and individual factors, generated by ongoing processes of residential segregation and labour market segmentation. Coinciding with Sweden's shift towards refugee and family dependent immigration, these processes are traced to public policies driving housing market liberalization and financialization, and labour market bifurcation. Reversal of the city's pronounced segregation, where cumulative interactions of segmentation processes cause a vicious circle of downward assimilation of less-qualified migrants and reactive ethnicity among marginalized immigrant youths, constitutes a formidable task Swedish Governments have so far failed to properly address.
暂无评论