Discriminative Shape Alignment

Abstract A fundamental challenge for behavioral neuroscientists is to accurately quantify (dis)similarities in animal behavior without excluding inherent variability present between individuals. We explored two new applications of curve and shape alignment techniques to address this issue. As a proof-of-concept we applied these methods to compare normal or alarmed behavior in pairs of medaka (Oryzias latipes). The curve alignment method we call Behavioral Distortion Distance (BDD) revealed that alarmed fish display less predictable swimming over time, even if individuals incorporate the same action patterns like immobility, sudden changes in swimming trajectory, or changing their position in the water column. The Conformal Spatiotemporal Distance (CSD) technique on the other hand revealed that, in spite of the unpredictability, alarmed individuals exhibit lower variability in overall swim patterns, possibly accounting for the widely held notion of “stereotypy” in alarm responses. More generally, we propose that these new applications of established computational geometric techniques are useful in combination to represent, compare, and quantify complex behaviors consisting of common action patterns that differ in duration, sequence, or frequency.

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Evaluating Shape Alignment via Ensemble Visualization

IEEE Computer Graphics and Applications ◽

10.1109/mcg.2015.70 ◽

2016 ◽

Vol 36 (3) ◽

pp. 60-71 ◽

Cited By ~ 6

Author(s):

Mukund Raj ◽

Mahsa Mirzargar ◽

J. Samuel Preston ◽

Robert M. Kirby ◽

Ross T. Whitaker

Keyword(s):

Shape Alignment ◽

Ensemble Visualization

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A Variational Framework for Partially Occluded Image Segmentation using Coarse to Fine Shape Alignment and Semi-Parametric Density Approximation

2007 IEEE International Conference on Image Processing ◽

10.1109/icip.2007.4378885 ◽

2007 ◽

Author(s):

Lin Yang ◽

David J. Foran

Keyword(s):

Image Segmentation ◽

Density Approximation ◽

Shape Alignment ◽

Parametric Density ◽

Variational Framework ◽

Partially Occluded ◽

Coarse To Fine

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Alignment of transtibial prostheses based on rollover shape principles

Prosthetics and Orthotics International ◽

10.1080/03093640308726664 ◽

2003 ◽

Vol 27 (2) ◽

pp. 89-99 ◽

Cited By ~ 35

Author(s):

A. H. Hansen ◽

M. R. Meier ◽

M. Sam ◽

D. S. Childress ◽

M. L. Edwards

Keyword(s):

Low Income ◽

A Priori ◽

The Elderly ◽

Low Income Countries ◽

Alignment Algorithm ◽

Shape Alignment ◽

Prosthetic Alignment ◽

Alignment System ◽

Prosthetic Feet ◽

The Ideal

The authors examined the rollover shape alignment hypothesis, which states that prosthetic feet are aligned by matching their rollover shapes with an “ideal” shape. The “ideal” shape was considered to be the rollover shape of the ablebodied footankle system. An alignment algorithm and computational alignment system were developed to set transtibial alignments based on this hypothesis. Three prosthetic feet with considerably different rollover shapes were either aligned using the alignment system or not aligned (i.e. used previous foot's alignment), and then were aligned by a team of prosthetists. No significant differences were found between rollover shapes aligned by the computational alignment system and those based on standard clinical techniques (p = 0.944). Significant differences were found between the “no alignment” shapes and the prosthetist alignment shapes (p = 0.006), and between the “no alignment” shapes and the computational alignment system shapes (p = 0.024). The results of the experiment support the hypothesis that the goal of alignment is to match the prosthetic foot's rollover shape, as closely as possible, with an “ideal” shape. The hypothesis is also supported by its ability to explain the results of previous studies. Using an “ideal” rollover shape or surface as a goal for prosthetic alignment could lead to a priori alignment, eliminating the need for alignment hardware in some cases. Being able to build the alignment into a prosthesis without special hardware could be beneficial in lowincome countries and in the fabrication of lightweight prostheses for the elderly.

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