Index Trees for Efficient Deformable Shape-based Retrieval

An improved method for deformable shape-based image indexing and retrieval is described. A pre-computed index tree is used to improve the speed of our previously reported on-line model fitting method; simple shape features are used as keys in a pre-generated index tree of model instances. In addition, a coarse to fine indexing scheme is used at different levels of the tree to further improve speed while maintaining matching accuracy. Experimental results show that the speedup is significant, while accuracy of shape-based indexing is maintained. A method for shape population-based retrieval is also described. The method allows query formulation based on the population distributions of shapes in each image. Results of population-based image queries for a database of blood cell micrographs are shown.Office of Naval Research (Young Investigator Award, N00014-96-1-066); National Science Foundation (IIS-9624168, EIA-9623865

The variation of head shapes in 17-20 years old native fars male in Gorgan-North of Iran

Cephalic index and head shape are affected by geographical, gender, age and racial factors. This study carried out to determine cephalic index and head shape in 17-20 years old native Fars male in Gorgan, North of Iran. This descriptive study was done on 200 of 17-20 years old male native Fars by classic cephalometry in Gorgan, North of Iran. Mean and SD of cephalic index was 84.8 ± 6.9. The head shape of 52% of individuals was hyperbrachycephalic, 25% brachycephalic, 21.5% mesocephalic and 1.5% dolichocephalic. Native Fars individuals showed typical hyperbrachycephalic. In comparing to other studies in world, we can conclude that the role of racial/ethnic factor in cephalic diameters. © 2006 Sociedad Chilena de Anatomía

The effect of ethnic factor on cephalic index in 17-20 years old females of north of Iran [Efecto del factor étnico en el índice cefálico en mujeres entre 17 y 20 años de edad del norte de Irán]

Cephalic index and head shape are affected by geographical, gender, age, racial and ethnic factors. This study was carried out to determine cephalic index and head shape in 17-20 years old female in Gorgan, North of Iran. This descriptive and cross sectional study is undertaken on 410 normal 17-20 years old female (Turkman group: n=203, Fars group: n=207). The study was done by classic cephalometry in Gorgan North of Iran. Means and SD of cephalic index was 85 ± 4.5 and 82.8 ± 3.6 in native Fars and Turkman groups, respectively. Dominant and rare type of head shape in native Fars group were hyperbrachycephalic (53.6%) and dolichocephalic (15%), and in Turkman group were brachycephalic (58.1%) and dolichocephalic (0.05%), respectively. With noticing of our results and other studies in the world, we can conclude that the role of ethnic factor on head dimensions. © 2007 Sociedad Chilena de Anatomía

Alternative Kullback-Leibler information entropy for enantiomers

In our series of studies on quantifying chirality, a new chirality measure is proposed in this work based on the Kullback-Leibler information entropy. The index computes the extra information that the shape function of one enantiomer carries over a normalized shape function of the racemate, while in our previous studies the shape functions of the R and S enantiomers were used considering one as reference for the other. Besides being mathematically more elegant (symmetric, positive definite, zero in the case of a nonchiral system), this new index bears a more direct relation with chirality oriented experimental measurements such as circular dichroism (CD) and optical rotation measurements, where the racemate is frequently used as a reference, The five chiral halomethanes holding one asymmetric carbon atom and H, F, Cl, Br, and I as substituents have been analyzed. A comparison with our calculated optical rotation and with Avnir's Continuous Chirality Measure (CCM) is computed. The results show that with this index the emphasis lies on the differences between the noncoinciding substituents

Object recognition using shape-from-shading

This paper investigates whether surface topography information extracted from intensity images using a recently reported shape-from-shading (SFS) algorithm can be used for the purposes of 3D object recognition. We consider how curvature and shape-index information delivered by this algorithm can be used to recognize objects based on their surface topography. We explore two contrasting object recognition strategies. The first of these is based on a low-level attribute summary and uses histograms of curvature and orientation measurements. The second approach is based on the structural arrangement of constant shape-index maximal patches and their associated region attributes. We show that region curvedness and a string ordering of the regions according to size provides recognition accuracy of about 96 percent. By polling various recognition schemes. including a graph matching method. we show that a recognition rate of 98-99 percent is achievable

An Angiosperm species dataset reveals relationships between seed size and two-dimensional shape

Datasets containing information on seed size have been published and are currently available. Nevertheless, there is a lack in the literature of a dataset dedicated to seed shape. We present a preliminary version for a dataset on seed morphology based on a comparison of seed shape with geometric figures. Similarity of the outline of seed images with geometric models is considered as a basis to classify seeds according to the geometric figures they resemble (e.g., ellipse, oval, cardioid). This allows, first, the classification of plant species according to their geometric type of seed, and second, seed shape quantification. For each seed image, the percent of similarity of their outline with a geometric figure can be calculated as a J index. Similarity in absolute terms is considered only when the J index >90. This criterion is important to avoid ambiguity and increase discrimination. The dataset opens the possibility of studying the relationship between seed shape and other variables such as seed size, genome complexity, life form or adaptive responses

Chaotic Waveguide-Based Resonators for Microlasers

We propose the construction of highly directional emission microlasers using two-dimensional high-index semiconductor waveguides as {\it open} resonators. The prototype waveguide is formed by two collinear leads connected to a cavity of certain shape. The proposed lasing mechanism requires that the shape of the cavity yield mixed chaotic ray dynamics so as to have the appropiate (phase space) resonance islands. These islands allow, via Heisenberg's uncertainty principle, the appearance of quasi bound states (QBS) which, in turn, propitiate the lasing mechanism. The energy values of the QBS are found through the solution of the Helmholtz equation. We use classical ray dynamics to predict the direction and intensity of the lasing produced by such open resonators for typical values of the index of refraction.Comment: 5 pages, 5 figure