• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1748-1759
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• 2018

Weber Local Descriptor (WLD) is a stable and effective feature extraction algorithm, which is based on Weber's Law. It calculates the differential excitation information and direction information, and then integrates them to get the feature information of the image. However, WLD only considers the center pixel and its contrast with its surrounding pixels when calculating the differential excitation information. As a result, the illumination variation is relatively sensitive, and the selection of the neighbor area is rather small. This may make the whole information is divided into small pieces, thus, it is difficult to be recognized. In order to overcome this problem, this paper proposes Weber Symmetrical Local Graph Structure (WSLGS), which constructs the graph structure based on the $5{\times}5$ neighborhood. Then the information obtained is regarded as the differential excitation information. Finally, we demonstrate the effectiveness of our proposed method on the database of ORL, JAFFE and our own built database, high-definition infrared faces. The experimental results show that WSLGS provides higher recognition rate and shorter image processing time compared with traditional algorithms.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.179-185
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• 1991

We examined optimum culture conditions of Rhodopseudomonas sphaeroides B5 for effective utilization of substrate and sunlight for hydrogen production. The optimum concentration range of DL-lactate as electron donor for hydrogen production by resting cells was from 5 to 50mM, and optimun CN ratio (lactate/glutamat) for maintenence of hydrogen production activity by growing cultures was from 5 to 6. Hydrogen production by the cultures of low cell density (0.36mg/ml dry cells) was saturated with 10 Klux light intensity. Under constant illumination of 50Klux which was set up as the average medium value of annual variation of sunlight intensity, hydrogen production with various cell densities in the culture resulted in highest production rate (132${\mu}$l/hr/mg dry cells) up to 0.64mg/ml dry cells. However, the amount of total hydrogen production was saturated with cell density of 2.1mg/ml dry cells. In addition to these, the optimum inner thickness pervious to light of the culture vessel for hydrogen production which was measured under sunlight was 5 cm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.58-64
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• 2016

In this paper presents Robust k-means clustering-based high-speed bar code decoding method to blur and lighting. for fast operation speed and robust decoding to blur, proposed method uses adaptive local threshold binarization methods that calculate threshold value by dividing blur region and a non-blurred region. Also, in order to prevent decoding fail from the noise, decoder based on k-means clustering algorithm is implemented using area data summed pixel width line of the same number of element. Results of simulation using samples taken at various worst case environment, the average success rate of proposed method is 98.47%. it showed the highest decoding success rate among the three comparison programs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.233-240
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• 2011

A field server was developed by using ubiquitous sensor network technology to monitor the abrupt weather variation in local or mountain area. The data transmissions between deployed field servers in local terrain are very important technology in disaster prevention monitoring system. Weather related information such as temperature, humidity, illumination, atmospheric pressure, dew point and meteorological data are collected from the designated field at a regular interval. The received information from the multiple sensors located at the sensor field is used flooding routing protocol transmission techniques and the sensing data is transferred to gateway through multi-hop method. Telosb sensor node are programmed by nesC language in TinyOS platform to monitor the weather parameters of the local terrain.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.67-73
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• 2010

In this paper, a new face detection method that is more accurate than the conventional methods is proposed. This method utilizes a hybrid of Hausdorff distance based on the geometric similarity between the two sets of points and the LBP distance based on the distribution of local micro texture of an image. The parameters for normalization and the optimal blending factor of the two different metrics were calculated from training sample images. Popularly used face database was used to show that the proposed method is more effective and robust to the variation of the pose, illumination, and back ground than the methods based on the Hausdorff distance or LBP distance. In the particular case, the average error distance between the detected and the true face location was reduced to 47.9% of the result of LBP method, and 22.8% of the result of Hausdorff method.

• The Journal of the Korea Contents Association
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• v.11 no.3
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• pp.18-25
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• 2011

In a manufacturing process of metal coins, surface defects of coins are manually detected. This paper describes an new method for detecting surface defects of metal coins on a moving conveyor belt using image processing. This method consists of multiple procedures: segmentation of a coin from the background, alignment of the coin to the model, projection of the aligned coin to the best eigen image space, and detection of defects by comparison of the projection error with an adaptive threshold. In these procedures, the alignement and the projection are newly developed in this paper for the detection of coin surface defects. For alignment, we use the histogram of the segmented coin, which converts two-dimensional image alignment to one-dimensional alignment. The projection reduces the intensity variation of the coin image caused by illumination and coin rotation change. For projection, we build multiple eigen image spaces and choose the best eigen space using estimated coin direction. Since each eigen space consists of a small number of eigen image vectors, we can implement the projection in real- time.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.145-145
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• 2011

Light-emitting diodes (LEDs) based on III-nitrides compound semiconductors have achieved a high performance device available for display and illumination sector. However, the conventional c-plane oriented LED structures are still showing several problems given by the quantum confined Stark effect (QCSE) due to the effects of strong piezoelectric and spontaneous polarizations. The QCSE results in spatial separation of electron and hole wavefunctions in quantum wells, thereby decreasing the internal quantum efficiency and red-shifting the emission wavelength. Due to demands for improvement of device performance, nonpolar structure has been attracting attentions, since the quantum wells grown on nonpolar templates are free from the QCSE. However, current device performance for nonpolar LEDs is still lower than those for conventional LEDs. In this study, we discuss the potential possibilities of nonpolar LEDs for commercialization. In this study, we characterized current-light output power relation of the a-plane InGaN/GaN LEDs structures with the variation of quantum well structures. On-wafer electroluminescence measurements were performed with short pulse (10 us) and low duty factor (1 %) conditions applied for eliminating thermal effects. The well and barrier widths, and indium compositions in quantum well structures were changed to analyze the efficiency droop phenomenon.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.45-52
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• 2003

Red ginsengs are inspected manually by examining those in the dark room with back light illumination. Manual inspection is often influenced by physical condition of inspectors. Sometimes. the best grade, heaven. has some inner holes though it was inspected by a specialist. In order to resolve this problem, this study was performed to develop image processing algorithm to detect the inner holes in the x-ray image of ginseng. Because of little gray value difference between background and ginseng in the image. simple thresholding method was not appropriate. Modified watershed algorithm was used to differentiate the inner holes from background and normal ginseng body. Inner hole edge region detected by watershed algorithm consists of many number of blobs including normal portions. With line profile analysis with scanning one line at a time beginning the starting point. it shelved two peaks both ends representing extracting each blobs. in which setting threshold value as of lower peak value enabled us to obtain inner hole image. Once this procedure has to be done till the finishing point it is completing inner hole detection for one blob. Thus. conducting ail blobs by this procedure is completing inner detection of one whole ginseng. Detection results of the inner holes fer various size of red ginsengs were good even though there was small detection variation. 6.2%. according to position of x-rat tube.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.74-78
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• 2007

We report theoretical and experimental results for application of transmittance-controlled photomask technology to ArF lithography. The transmittance-controlled photomask technology is thought to be a promising technique fo critical dimension (CD) uniformity correction on a wafer by use of phase patterns on the backside of a photomask. We could theoretically reproduce experimental results for illumination intensity drop with respect to the variation of backside phase patterns by considering light propagation from the backside to the front side of a photomask at the ArF lithography wavelength. We applied the transmittance-controlled photomask technology to ArF lithography for a critical layer of DRAM (Dynamic Random Access Memory) having a 110-nm design rule and found that the in-field CD uniformity value was improved from 13.8 nm to 9.7 nm in $3{\sigma}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.1-8
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• 1984

The tools and techniques for measuring the spectral distribution of light emitted by, transmitted by, or reflected from food surfaces are described for determining the extent to which original natural color is preserved in processing and subsequent storage of foods. Color differences may be evaluated indirectly in terms of some physical characteristic of the sample or extracted fraction thereof that is largely responsible for the color characteristics. For evaluation more directly in terms of what the observer actually seen, color differences are measured by reflectance spectrophotometry and photoelectric colorimetry and expressed as differences in psychophysical indexes such as luminous reflectance and chromaticity. The standard system, against which other systems could be compared, is the one recommended by the International Committee on illumination and which is based on the 'standard observer', which is a simulated standard eye, consisting of three primary color filters Z, with X being essentially amber in color, Y, green and Z, blue. Any spectrophotometric curve of reflectance obtained from the surface of an object can be integrated in terms of X, Y and Z. Psychophysical notation may be converted by standard methods to the colorimetrically more descriptive terms of Munsell hue, value and chroma.