Browsing by Subject "Spectral content"

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Open Access
Detection of heterogeneous structures using hierarchical segmentation
(IEEE, 2011) Akçay, H. Gokhan; Aksoy, Selim
We present an unsupervised hierarchical segmentation algorithm for detecting complex heterogeneous image structures that are comprised of simpler homogeneous primitive objects. The first step segments primitive objects with uniform spectral content. Then, the co-occurrence information between neighboring regions is modeled and clustered. We assume that dense clusters of this co-occurrence space can be considered significant. Finally, the neighboring regions within these clusters are merged to obtain the next level in the segmentation hierarchy. The experiments show that the algorithm that iteratively clusters and merges region groups is able to segment heterogeneous structures in a hierarchical manner. © 2011 IEEE.
Open Access
Finding compound structures in images using image segmentation and graph-based knowledge discovery
(IEEE, 2009-07) Zamalieva, Daniya; Aksoy, Selim; Tilton J. C.
We present an unsupervised method for discovering compound image structures that are comprised of simpler primitive objects. An initial segmentation step produces image regions with homogeneous spectral content. Then, the segmentation is translated into a relational graph structure whose nodes correspond to the regions and the edges represent the relationships between these regions. We assume that the region objects that appear together frequently can be considered as strongly related. This relation is modeled using the transition frequencies between neighboring regions, and the significant relations are found as the modes of a probability distribution estimated using the features of these transitions. Experiments using an Ikonos image show that subgraphs found within the graph representing the whole image correspond to parts of different high-level compound structures. ©2009 IEEE.
Open Access
Hierarchical segmentation of complex structures
(IEEE, 2010) Akçay, H. Gökhan; Aksoy, Selim; Soille P.
We present an unsupervised hierarchical segmentation algorithm for detection of complex heterogeneous image structures that are comprised of simpler homogeneous primitive objects. An initial segmentation step produces regions corresponding to primitive objects with uniform spectral content. Next, the transitions between neighboring regions are modeled and clustered. We assume that the clusters that are dense and large enough in this transition space can be considered as significant. Then, the neighboring regions belonging to the significant clusters are merged to obtain the next level in the hierarchy. The experiments show that the algorithm that iteratively clusters and merges region groups is able to segment high-level complex structures in a hierarchical manner. © 2010 IEEE.