• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2809-2815
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• 1999

Level set, and active contour(snakes) models are extensively used for image segmentation or shape extraction in computer vision. Snakes utilize the energy minimization concepts, and level set is based on the curve evolution in order to extract contours from image data. In general, these two models have their own drawbacks. For instance, snake acts pooly unless it is placed close to the wanted shape boundary, and it has difficult problem when image has multiple objects to be extracted. But, level set method is free of initial curve position problem, and has ability to handle topology of multiple objects. Nevertheless, level set method requires much more calculation time compared to snake model. In this paper, we use good points of two described models and also apply multi resolution algorithm in order to speed up the process without decreasing the performance of the shape extraction.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2798-2800
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• 2003

Active contour models(called Snakes) are methods for the image segmentation. Many researchers have developed snake algorithms and then published such as GVF, GGF snake. In this paper, we present a pre-process for GGF snake algorithm. This process removes noise so that snakes can flow smoothly. In experiment, we compared a image removed noise with a image corrupted by noise. In result, the pre-process produced a good image for GGF Snake and is necessary.

• Journal of the korean veterinary medical association
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• v.50 no.4
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• pp.253-255
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• 2014

• Journal of the korean veterinary medical association
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• v.50 no.5
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• pp.316-319
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• 2014

• Parasites, Hosts and Diseases
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• v.54 no.4
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• pp.423-429
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• 2016

Cryptosporidium is an important pathogen causing gastrointestinal disease in snakes and is distributed worldwide. The main objectives of this study were to detect and identify Cryptosporidium species in captive snakes from exotic pet shops and snake farms in Thailand. In total, 165 fecal samples were examined from 8 snake species, boa constrictor (Boa constrictor constrictor), corn snake (Elaphe guttata), ball python (Python regius), milk snake (Lampropeltis triangulum), king snake (Lampropeltis getula), rock python (Python sebae), rainbow boa (Epicrates cenchria), and carpet python (Morelia spilota). Cryptosporidium oocysts were examined using the dimethyl sulfoxide (DMSO)-modified acid-fast staining and a molecular method based on nested-PCR, PCR-RFLP analysis, and sequencing amplification of the SSU rRNA gene. DMSO-modified acid-fast staining revealed the presence of Cryptosporidium oocysts in 12 out of 165 (7.3%) samples, whereas PCR produced positive results in 40 (24.2%) samples. Molecular characterization indicated the presence of Cryptosporidium parvum (mouse genotype) as the most common species in 24 samples (60%) from 5 species of snake followed by Cryptosporidium serpentis in 9 samples (22.5%) from 2 species of snake and Cryptosporidium muris in 3 samples (7.5%) from P. regius.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.705-716
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• 2002

This paper proposes a method which visualizes MRI head data in 3 dimensions with direct volume rendering. Though surface rendering is usually used for MRI data visualization, it has some limits of displaying little speckles because it loses the information of the speckles in the surfaces while acquiring the information. Direct volume rendering has ability of displaying little speckles, but it doesn't treat MRI data because of the data features of MRI. In this paper, we try to visualize MRI head data in 3 dimensions as follows. First, we separate the brain region from the head region of MRI head data, next increase the pixel level of the brain region, then combine the brain region with the increased pixel level and the head region without brain region, last visualizes the combined MRI head data with direct volume rendering. We segment the brain region from head region based on histogram threshold, morphology operations and snakes algorithm. The proposed segmentation method shows 91~95% similarity with a hand segmentation. The method rather clearly visualizes the organs of the head in 3 dimensions.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.42-53
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• 2017

One of the negative ecological effects following road construction is roadkill; animals die on the roads after being struck by vehicles. Roadkills have been a major concern in South Korea due to the large mountain areas in the country and have been mentioned as a causal factor for the decline in wildlife. Although snake roadkills frequently occur, as with mammals, birds, and amphibians, there are not many related studies done on snake roadkills. In this study, we determined snake roadkill patterns in the northeast part of South Korea including most of the Gangwon-do areas and parts of Gyeonggi-do, Chungcheongbuk-do, and Gyeongsangbuk-do by analyzing the snake roadkills found between May 2007 and Aug 2012. We identified a total of 155 roadkilled snakes from 10 different species. Red-sided water snake (Rhabdophis tigrinus), Red-tongue viper snake (Gloydius ussuriensis), Cat snake (Elaphe dione), Red-banded snake (Dinodon rufozonatus), and Viper snake (Gloydius brevicaudus) accounted for more than 90% of the total cases. It was found that more active forager snakes were killed than sit-and-wait foragers, more male snakes were killed than female snakes, and more adult snakes were killed than subadult snakes. The snake roadkill frequency was the highest in September between the altitudes of 200 and 400 m, and on roads between either a mountain and a body of water or between a mountain and a crop field. Our results are expected to enhance the understanding of snake roadkills in general and to determine the areas, specific sites and species for planning projects for snake roadkill reduction in the northeast of South Korea.

• Journal of KIISE:Software and Applications
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• v.27 no.7
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• pp.731-741
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• 2000

This paper proposes a method to detect a facial region and extract facial features which is crucial for visual recognition of human faces. In this paper, we extract the MER(Minimum Enclosing Rectangle) of a face and facial components using projection analysis on both edge image and binary image. We use an active contour model(snakes) for extraction of the contours of eye, mouth, eyebrow, and face in order to reflect the individual differences of facial shapes and converge quickly. The determination of initial contour is very important for the performance of snakes. Particularly, we detect Minimum Enclosing Rectangle(MER) of facial components and then determine initial contours using general shape of facial components within the boundary of the obtained MER. We obtained experimental results to show that MER extraction of the eye, mouth, and face was performed successfully. But in the case of images with bright eyebrow, MER extraction of eyebrow was performed poorly. We obtained good contour extraction with the individual differences of facial shapes. Particularly, in the eye contour extraction, we combined edges by first order derivative operator and zero crossings by second order derivative operator in designing energy function of snakes, and we achieved good eye contours. For the face contour extraction, we used both edges and grey level intensity of pixels in designing of energy function. Good face contours were extracted as well.

• Korean Journal of Environment and Ecology
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• v.31 no.5
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• pp.455-460
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• 2017

Since a new (unrecorded) species was reported in 2016, a total of four sea snake species are currently listed in Korean waters. Although the possibility of year-round inhabitation of sea snakes in Korean waters has increased due to climate change, the related studies are scarce because of the lack of human resources and available equipment. We placed posters and banners requesting voluntary information on sea snakes in coastal regions and Jeju Island to obtain information on sea snake distributions in the coasts of South Korea and possible specimens through volunteer activities. As a result, we received total 45 reliable reports, including photographs or video, between March 2013 and December 2016. Eighteen reports on three sea snake species and thirteen capture cases of two species were submitted from Jeju Island and southern coastal regions of Korea mostly between August and November. There were twenty-seven false reports including seven cases of terrestrial snakes, eighteen fishes, and one each of invertebrate and inanimate material. Based on the results, we proposed the effective way of sea snake surveys using volunteers.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.85-92
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• 2014

In order to study the home range of the red-tongue viper snake (Gloydis ussuriensis) and the short-tailed viper snake (Gloydius saxatilis) belonging to the viperidae of squamat in Korea, we implanted radio-transmitters which were weighed less than 5% of individual mass in them and traced their location by radio-tracking. Surgeries for transmitter insertion were performed on 5 red-tongue viper snakes and 6 short-tailed viper snakes (total 11 individuals) and the average ratio of transmitter mass to body mass were 4.2% and 2.2%, respectively. After radio-transmitter implantation, all short-tailed viper snakes survived but 4 out of 5 red-tongue viper snakes did not survive during the convalescence stage, showing only 20% of survival rate. The results suggest that the ratio of transmitter mass to body mass should be less than 3.6% at least in these species, although previous studies have recommended various ranges from 1% to 7% as the acceptable ratios.