• 동력기계공학회지
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• 제20권4호
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• pp.32-37
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• 2016

This paper proposes two measurement methods for injured rate of fish surface using color image segmentation method based on K-means clustering algorithm and Otsu's threshold algorithm. To do this task, the following steps are done. Firstly, an RGB color image of the fish is obtained by the CCD color camera and then converted from RGB to HSI. Secondly, the S channel is extracted from HSI color space. Thirdly, by applying the K-means clustering algorithm to the HSI color space and applying the Otsu's threshold algorithm to the S channel of HSI color space, the binary images are obtained. Fourthly, morphological processes such as dilation and erosion, etc. are applied to the binary image. Fifthly, to count the number of pixels, the connected-component labeling is adopted and the defined injured rate is gotten by calculating the pixels on the labeled images. Finally, to compare the performances of the proposed two measurement methods based on the K-means clustering algorithm and the Otsu's threshold algorithm, the edge detection of the final binary image after morphological processing is done and matched with the gray image of the original RGB image obtained by CCD camera. The results show that the detected edge of injured part by the K-means clustering algorithm is more close to real injured edge than that by the Otsu' threshold algorithm.

• 한국멀티미디어학회논문지
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• 제8권7호
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• pp.961-973
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• 2005

본 논문은 비트플레인 및 다중채널 특성을 이용한 컬러 영상의 적응 스테가노그라피 방법을 제안하였다. RGB 채널의 모든 비트플레인에 고정 임계값을 적용하여 정보를 삽입한 결과, 채널에 따른 화질 열화의 차이를 알 수 있었다. 따라서 본 연구에서는 BPCS (bit-plane complexity steganography) 방법의 고정 임계값 문제점을 해결하고 삽입용량과 화질을 개선하기 위하여 각 채널과 비트플레인 가중치를 정의하였다. 또한 비트플레인의 삽입 용량을 적응적으로 증가시키기 위하여, 커버 영상의 비트플레인 복잡도와 채널별 가중치를 이용하여 새로운 적응 임계값 설정 방법을 제안하였다. 실험에서는 컬러 영상에 동일한 화질과 동일한 정보량을 삽입하고, 이에 따른 삽입 용량과 채널별 화질을 비교하였다. 그 결과, 제안한 방법이 기존의 BPCS 방법보다 삽입 용량의 증가와 채널별 화질도 향상되었다.

• Applied Microscopy
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• 제46권1호
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• pp.6-13
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• 2016

Fluorescence lifetime imaging microscopy (FLIM) has been considered an effective technique to investigate chemical properties of the specimens, especially of biological samples. Despite of this advantageous trait, researchers in this field have had difficulties applying FLIM to their systems because acquiring an image using FLIM consumes too much time. Although analog mean-delay (AMD) method was introduced to enhance the imaging speed of commonly used FLIM based on time-correlated single photon counting (TCSPC), a real-time image reconstruction using AMD method has not been implemented due to its data processing obstacles. In this paper, we introduce a real-time image restoration of AMD-FLIM through fast parallel data processing by using Threading Building Blocks (TBB; Intel) and octa-core processor (i7-5960x; Intel). Frame rate of 3.8 frames per second was achieved in $1,024{\times}1,024$ resolution with over 4 million lifetime determinations per second and measurement error within 10%. This image acquisition speed is 184 times faster than that of single-channel TCSPC and 9.2 times faster than that of 8-channel TCSPC (state-of-art photon counting rate of 80 million counts per second) with the same lifetime accuracy of 10% and the same pixel resolution.

• Current Optics and Photonics
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• 제3권1호
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• pp.27-32
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• 2019

We present an autofocus tracking system implemented by the digital refocusing of digital holographic microscopy (DHM) and the tunability of an electrically tunable lens (ETL). Once the defocusing distance of an image is calculated with the DHM, then the focal plane of the imaging system is optically tuned so that it always gives a well-focused image regardless of the object location. The accuracy of the focus is evaluated by calculating the contrast of refocused images. The DHM is performed in an off-axis holographic configuration, and the ETL performs the focal plane tuning. With this proposed system, we can easily track down the object drifting along the depth direction without using any physical scanning. In addition, the proposed system can simultaneously obtain the digital hologram and the optical image by using the RGB channels of a color camera. In our experiment, the digital hologram is obtained by using the red channel and the optical image is obtained by the blue channel of the same camera at the same time. This technique is expected to find a good application in the long-term imaging of various floating cells.

• 한국게임학회 논문지
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• 제21권6호
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• pp.3-12
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• 2021

본 논문은 게임산업에서 브랜드 인지도와 브랜드 이미지에 영향을 미치는 주요 변수들의 관계와 브랜드 충성도 형성 과정을 실증분석 했다. 이를 위해, K-BPI 데이터로 5가지의 주요 변수 간 6가지 가설을 세우고 검정하였다. 그 결과, 브랜드 인지도에 미치는 효과는 유통접근성 만이 유의한 반면, 브랜드 이미지에는 마케팅 커뮤니케이션과 유통접근성 모두 유의한 효과를 보이는 것으로 나타났다. 브랜드 충성도에는 브랜드 이미지만 유의한 효과를 보였다. 따라서, 게임산업의 마케팅 커뮤니케이션 활동의 목표는 브랜드 이미지 개선으로 하는 것이 바람직하며, 체험과 같은 소비경험을 제고하는 전략이 중요한 것으로 보인다.

• Journal of Information Processing Systems
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• 제19권4호
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• pp.427-438
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• 2023

Plenty of works have indicated that single image super-resolution (SISR) models relying on synthetic datasets are difficult to be applied to real scene text image super-resolution (STISR) for its more complex degradation. The up-to-date dataset for realistic STISR is called TextZoom, while the current methods trained on this dataset have not considered the effect of multi-scale features of text images. In this paper, a multi-scale and attention fusion model for realistic STISR is proposed. The multi-scale learning mechanism is introduced to acquire sophisticated feature representations of text images; The spatial and channel attentions are introduced to capture the local information and inter-channel interaction information of text images; At last, this paper designs a multi-scale residual attention module by skillfully fusing multi-scale learning and attention mechanisms. The experiments on TextZoom demonstrate that the model proposed increases scene text recognition's (ASTER) average recognition accuracy by 1.2% compared to text super-resolution network.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.30-35
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• 2003

Flow characteristics of blood flow in a micro channel were investigated experimentally using a micro-PIV (Particle Image Velocimetry) velocity field measurement technique. The main objective of this study was to understand the real blood flow in micron-sized blood vessels. The Reynolds number based on the hydraulic diameter of micro-channel for deionized (DI) water was about Re=0.34. For each experimental condition, 100 instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity. In addition, the motion of RBC (Red Blood Cell) was visualized with a high-speed CCD camera. The captured flow images of nano-scale fluorescent tracer particles in DI water were clear and gave good velocity tracking-ability. However, there were substantial velocity variations in the central region of real blood flow in a micro-channel due to the presence of red blood cells.

• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.793-799
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• 2006

In this paper, the gate leakage current is first calculated using the experimental method between gate and drain by opening source electrode. the gate to drain current has been obtained with ground source. The difference between two currents has been tested and proves that the electric field generated by channel charge effect against the image force lowering.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.44-49
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• 2011

The need of data transmission in oceans and other underwater mediums are increasing day by day, so as the research. The underwater medium is very different from that of air. Propagation of electromagnetic wave in water or underground is very difficult because of the conductivity of the propagation materials. In this case, we usually use acoustic signals as ultrasonic but, they are not easy to transfer long distance with coherent method because of time varying multipaths, Doppler effects and attenuations. So, we use non-coherent methods such as FSK or ASK to communicate between long distances. But, as the propagation speed of acoustic wave is very slow, BW of the channel is narrow. It is very hard to guaranty the enough speed for the transmission of digital image data. In previous studies, we proposed this data communication protocol theoretically. In this paper, an underwater channel is modeled and this protocol is tested in this channel condition. The results show that the protocol is 4-6 times faster than ASK. Some relations and results are shown depending on the data length, channel length, bit rate etc.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.257-264
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• 2019

본 논문에서는 픽셀 기반 joint BDCP (bright and dark channel prior)와 계층적 양방향 필터를 적용하여 저 복잡도를 갖는 단일 영상 기반 안개 제거 기법을 제안한다. 픽셀 기반 joint BDCP는 기존의 패치 기반 DCP에 비해 연산량을 감소시키고, 픽셀 단위의 안개값 예측을 가능하게 하여 전달량 추정의 정확성을 높인다. 또한 에지를 보존하면서 평탄화 성능이 우수한 양방향 필터를 사용하여 전달량을 정련함으로써 후광 효과(halo effect)를 줄이고, 에지 성분에 대한 계층적 적용을 통해 반복 적용에 의한 연산량의 증가를 방지한다. 안개 성분이 포함된 다양한 영상에 대해 수행한 실험 결과는 제안하는 기법이 기존의 기법에 비해 우수한 안개 제거 성능을 보이면서 저 복잡도로 실행되어 다양한 분야에 응용될 수 있음을 나타낸다.