Grouping and segmentation in a hierarchy of graphs
We review multilevel hierarchies under the special aspect of their potential for segmentation and grouping. The one-to-one correspondence between salient image features and salient model features are ...
Alternating minimization multigrid algorithms for transmission tomography
The problem of image formation for X-ray transmission tomography is formulated as a statistical inverse problem. The maximum likelihood estimate of the attenuation function is sought. Using convex opt...
Proc. SPIE, Vol. 5299, 205 (2004);
doi:10.1117/12.543423
Online Publication Date: 25 June 2004
Conference Date: Monday 19 January 2004
Conference Location: San Jose, CA, USA
Conference Title: Computational Imaging II
Conference Chairs: Charles A. Bouman, Eric L. Miller
Priortheories have assumed that human problem solving involves estimating distancesamong states and performing search through the problem space. Therole of mental representation in those theories was minimal. Resultsof our recent experiments suggest that humans are able tosolve some difficult problems quickly and accurately. Specifically, in solvingthese problems humans do not seem to rely on distancesor on search. It is quite clear that producing goodsolutions without performing search requires a very effective mental representation.In this paper we concentrate on studying the nature ofthis representation. Our theory takes the form of a graphpyramid. To verify the psychological plausibility of this theory wetested subjects in a Euclidean Traveling Salesman Problem in thepresence of obstacles. The role of the number and sizeof obstacles was tested for problems with 6-50 cities. Weanalyzed the effect of experimental conditions on solution time percity and on solution error. The main result is thattime per city is systematically affected only by the sizeof obstacles, but not by their number, or by thenumber of cities.