Measurement of asymmetry of stripe patterns in animals
22 Jul 2012-pp 1-5
TL;DR: In this article, the deviation from perfect symmetry of the left and right sides of a bilateral animal is known to indicate the developmental stress of the animal and has been used to study the general health of a population.
Abstract: The deviation from perfect symmetry of the left and right sides of a bilateral animal is known to indicate the developmental stress of the animal. It has also been used to study the general health of a population. For animals like tigers and zebras which have natural stripes on their bodies, the asymmetry between the two sides can be measured by analysing the stripe patterns taken from images of these animals. In this paper we propose an algorithm for measuring this asymmetry. We use a Short-Time Fourier Transform based approach to measure the local frequencies at different locations and compare the resulting frequency maps. The mean absolute error between the left and right frequency maps yields a measure of the asymmetry. Our results show a surprising level of asymmetry in tiger stripes compared to zebras.
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Journal Article•
TL;DR: A new framework is presented to take into account the social media bias when using this data source to provide wildlife population size estimates and it is shown that, surprisingly, this is a learnable and potentially solvable problem.
Abstract: We are losing biodiversity at an unprecedented scale and in many cases, we do not even know the basic data for the species. Traditional methods for wildlife monitoring are inadequate. Development of new computer vision tools enables the use of images as the source of information about wildlife. Social media is the rich source of wildlife images, which come with a huge bias, thus thwarting traditional population size estimate approaches. Here, we present a new framework to take into account the social media bias when using this data source to provide wildlife population size estimates. We show that, surprisingly, this is a learnable and potentially solvable problem.
5 citations
Cites background from "Measurement of asymmetry of stripe ..."
...Since not all animal species exhibit bilateral symmetry [46], it may be the case that an individual cannot be identified in every picture....
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TL;DR: This is the first known use of geometric morphometrics to quantify coat pattern uniqueness, using a model species to provide baseline individual morphological variation, and measures of coat pattern similarity have a place in phenotypic monitoring and identification.
3 citations
References
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TL;DR: A new definition of scale-space is suggested, and a class of algorithms used to realize a diffusion process is introduced, chosen to vary spatially in such a way as to encourage intra Region smoothing rather than interregion smoothing.
Abstract: A new definition of scale-space is suggested, and a class of algorithms used to realize a diffusion process is introduced. The diffusion coefficient is chosen to vary spatially in such a way as to encourage intraregion smoothing rather than interregion smoothing. It is shown that the 'no new maxima should be generated at coarse scales' property of conventional scale space is preserved. As the region boundaries in the approach remain sharp, a high-quality edge detector which successfully exploits global information is obtained. Experimental results are shown on a number of images. Parallel hardware implementations are made feasible because the algorithm involves elementary, local operations replicated over the image. >
12,560 citations
"Measurement of asymmetry of stripe ..." refers methods in this paper
...The corrected patch is given by IN (i, j) = I(i, j)−mI σI (3)...
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20 Jun 2005
TL;DR: The face recognition grand challenge (FRGC) is designed to achieve this performance goal by presenting to researchers a six-experiment challenge problem along with data corpus of 50,000 images.
Abstract: Over the last couple of years, face recognition researchers have been developing new techniques. These developments are being fueled by advances in computer vision techniques, computer design, sensor design, and interest in fielding face recognition systems. Such advances hold the promise of reducing the error rate in face recognition systems by an order of magnitude over Face Recognition Vendor Test (FRVT) 2002 results. The face recognition grand challenge (FRGC) is designed to achieve this performance goal by presenting to researchers a six-experiment challenge problem along with data corpus of 50,000 images. The data consists of 3D scans and high resolution still imagery taken under controlled and uncontrolled conditions. This paper describes the challenge problem, data corpus, and presents baseline performance and preliminary results on natural statistics of facial imagery.
2,595 citations
"Measurement of asymmetry of stripe ..." refers methods in this paper
...We use the same values for our application as well....
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TL;DR: A fast fingerprint enhancement algorithm is presented, which can adaptively improve the clarity of ridge and valley structures of input fingerprint images based on the estimated local ridge orientation and frequency.
Abstract: In order to ensure that the performance of an automatic fingerprint identification/verification system will be robust with respect to the quality of input fingerprint images, it is essential to incorporate a fingerprint enhancement algorithm in the minutiae extraction module. We present a fast fingerprint enhancement algorithm, which can adaptively improve the clarity of ridge and valley structures of input fingerprint images based on the estimated local ridge orientation and frequency. We have evaluated the performance of the image enhancement algorithm using the goodness index of the extracted minutiae and the accuracy of an online fingerprint verification system. Experimental results show that incorporating the enhancement algorithm improves both the goodness index and the verification accuracy.
2,212 citations
"Measurement of asymmetry of stripe ..." refers methods in this paper
...We use the same values for our application as well....
[...]
...The corrected patch is given by IN (i, j) = I(i, j)−mI σI (3)...
[...]
TL;DR: Why, then, all the recent (and not so recent) interest in such minor, nondirectional deviations from bilateral symmetry [fluctuating asymmetry (FA)?
Abstract: With these words Darwin opened a brief paragraph citing observations antithetical to his supposition: anecdotal reports of the inheritance of characters missing from one side of the body. His initial hunch, however, has stood the test of time: Genetic studies have confirmed that where only small, random deviations from bilateral symmetry exist, the deviations in a particular direction have little or no measurable heritability (17, 47, 51, 65a, 73a, 74, 91). The genetic basis of bilateral symmetry thus appears to differ fundamentally from that of virtually all other morphological features. Why, then, all the recent (and not so recent) interest in such minor, nondirectional deviations from bilateral symmetry [fluctuating asymmetry (FA); 60 cited in 99]? Four reasons. First, FA relates in a curious way to what is perhaps the major unsolved general problem in modem biology: the orderly expression of genotypes as complex, three-dimensional phenotypes. As was emphasized in a flurry of activity in the mid to late 1950s, and many times since, FA provides an appealing measure of 'developmental noise,' or minor environmentally induced departures from some ideal developmental program (101). Its appeal derives from an a priori knowledge of the ideal: perfect bilateral symmetry. For unilateral characters, the ideal is rarely known (but see 1, 2, and 59 for one possible approach). A second reason for interest in
2,025 citations
"Measurement of asymmetry of stripe ..." refers background in this paper
...This deviation, (called Fluctuating Asymmetry) is thought to reflect stresses during development of the animal [1]....
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TL;DR: This work presents a multiscale method in which a nonlinear diffusion filter is steered by the so-called interest operator (second-moment matrix, structure tensor), and an m-dimensional formulation of this method is analysed with respect to its well-posedness and scale-space properties.
Abstract: The completion of interrupted lines or the enhancement of flow-like structures is a challenging task in computer vision, human vision, and image processing. We address this problem by presenting a multiscale method in which a nonlinear diffusion filter is steered by the so-called interest operator (second-moment matrix, structure tensor). An m-dimensional formulation of this method is analysed with respect to its well-posedness and scale-space properties. An efficient scheme is presented which uses a stabilization by a semi-implicit additive operator splitting (AOS), and the scale-space behaviour of this method is illustrated by applying it to both 2-D and 3-D images.
868 citations
"Measurement of asymmetry of stripe ..." refers methods in this paper
...The corrected patch is given by IN (i, j) = I(i, j)−mI σI (3)...
[...]