• Title/Summary/Keyword: Local histogram equalization

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Extraction of Tongue Region using Graph and Geometric Information (그래프 및 기하 정보를 이용한 설진 영역 추출)

  • Kim, Keun-Ho;Lee, Jeon;Choi, Eun-Ji;Ryu, Hyun-Hee;Kim, Jong-Yeol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.11
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    • pp.2051-2057
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    • 2007
  • In Oriental medicine, the status of a tongue is the important indicator to diagnose one's health like physiological and clinicopathological changes of inner parts of the body. The method of tongue diagnosis is not only convenient but also non-invasive and widely used in Oriental medicine. However, tongue diagnosis is affected by examination circumstances a lot like a light source, patient's posture and doctor's condition. To develop an automatic tongue diagnosis system for an objective and standardized diagnosis, segmenting a tongue is inevitable but difficult since the colors of a tongue, lips and skin in a mouth are similar. The proposed method includes preprocessing, graph-based over-segmentation, detecting positions with a local minimum over shading, detecting edge with color difference and estimating edge geometry from the probable structure of a tongue, where preprocessing performs down-sampling to reduce computation time, histogram equalization and edge enhancement. A tongue was segmented from a face image with a tongue from a digital tongue diagnosis system by the proposed method. According to three oriental medical doctors' evaluation, it produced the segmented region to include effective information and exclude a non-tongue region. It can be used to make an objective and standardized diagnosis.

Automatic Registration between Multiple IR Images Using Simple Pre-processing Method and Modified Local Features Extraction Algorithm (단순 전처리 방법과 수정된 지역적 피쳐 추출기법을 이용한 다중 적외선영상 자동 기하보정)

  • Kim, Dae Sung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.6
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    • pp.485-494
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    • 2017
  • This study focuses on automatic image registration between multiple IR images using simple preprocessing method and modified local feature extraction algorithm. The input images were preprocessed by using the median and absolute value after histogram equalization, and it could be effectively applied to reduce the brightness difference value between images by applying the similarity of extracted features to the concept of angle instead of distance. The results were evaluated using visual and inverse RMSE methods. The features that could not be achieved by the existing local feature extraction technique showed high image matching reliability and application convenience. It is expected that this method can be used as one of the automatic registration methods between multi-sensor images under specific conditions.

Implementation of Image Enhancement Filter System Using Genetic Algorithm (유전자 알고리즘을 이용한 영상개선 필터 시스템 구현)

  • Gu, Ji-Hun;Dong, Seong-Su;Lee, Jong-Ho
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.51 no.8
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    • pp.360-367
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    • 2002
  • In this paper, genetic algorithm based adaptive image enhancement filtering scheme is proposed and Implemented on FPGA board. Conventional filtering methods require a priori noise information for image enhancement. In general, if a priori information of noise is not available, heuristic intuition or time consuming recursive calculations are required for image enhancement. Contrary to the conventional filtering methods, the proposed filter system can find optimal combination of filters as well as their sequent order and parameter values adaptively to unknown noise types using structured genetic algorithms. The proposed image enhancement filter system is mainly composed of two blocks. The first block consists of genetic algorithm part and fitness evaluation part. And the second block consists of four types of filters. The first block (genetic algorithms and fitness evaluation blocks) is implemented on host computer using C code, and the second block is implemented on re-configurabe FPGA board. For gray scale control, smoothing and deblurring, four types of filters(median filter, histogram equalization filter, local enhancement filter, and 2D FIR filter) are implemented on FPGA. For evaluation, three types of noises are used and experimental results show that the Proposed scheme can generate optimal set of filters adaptively without a pioi noise information.

A Study on the Recognition of Defected Fingerprint Using Chain Code (체인 코드를 이용한 훼손된 지문의 인식에 관한 연구)

  • 조민환
    • Journal of the Korea Society of Computer and Information
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    • v.8 no.4
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    • pp.63-68
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    • 2003
  • Almost the system are usually taken by means of shapes and positions of ridge's end-points and bifurcation in the fingerprint recognition. but we studied about recognition of polluted fingerprint by chain code ridges. the results and sequence of processing are summarized as follows. (1)Capture several kinds of polluted fingerprint image. (2)Preprocessing(median filtering for removing noises, local and global histogram equalization, dilation and erosion, thinning and remove pseudo image), (3)Rebuild ridge line after Least Square Processing, (4)Compute distribution of chain code vector, (5)The results are almost same values of each vector of preprocessed fingerprint images. From the results, we can surmised more successful fingerprints recognition system in combination with other system by singular points

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Local Histogram Equalization Method based on Multiple Layers Overlapped Block for Image Contrast Enhancement (이미지 컨트라스트 향상을 위한 다중 레이어 오버랩 블록 기반 로컬 히스토그램 평활화 기법)

  • Kim, Min-Sil;Kim, Jong-Ho;Choe, Yoon-Sik
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2012.07a
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    • pp.279-282
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    • 2012
  • 로컬 히스토그램 평활화(LHE)는 영상에서 로컬 정보를 강조하기 위한 효율적인 알고리즘 중 하나이다. 그러나 이 알고리즘은 스펙클 노이즈를 증폭시키는 단점을 가진다. 따라서, 기존의 로컬 히스토그램 평활화 기법을 확장한 다중 레이어 블록 오버랩 히스토그램 평활화 기법을 이용하여 기존 로컬 히스토그램 평활화 기법들의 문제점을 해결하고자 하였다. 이 방법은 3단계-컨트라스트 향상 단계, 노이즈 제거 단계, 통합 단계로 이루어진다. 제안된 방법에서는 기존 방법의 컨트라스트 향상 단계에서 일반적인 로컬 히스토그램 평활화 방법이 아닌 컨트라스트를 제한하는 적응적인 히스토그램 평활화 기법을 적용하고, 노이즈 제거 단계에서 새로운 바이레터럴 필터를 적용하였다. 즉, 기존 방법의 문제점들을 해결하도록 알고리즘을 변형하여 기존 알고리즘의 성능을 개선하였다. 실험 결과는 제안된 방법이 기존의 방법 및 잘 알려진 로컬 히스토그램 평활화 기법들과 비교하여 좋은 성능을 내는 것을 확인하였다.

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Application Feasibility Study of Non-local Means Algorithm in a Miniaturized Vein Near-infrared Imaging System (정맥 관찰용 소형 근적외선 영상 시스템에서의 비지역적평균 알고리즘 적용 가능성 연구)

  • Hyun-Woo Jeong;Youngjin Lee
    • Journal of the Korean Society of Radiology
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    • v.17 no.5
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    • pp.679-684
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    • 2023
  • Venous puncture is widely used to obtain blood samples for pathological examination. Because the invasive venipuncture method using a needle is repeatedly performed, the pain suffered by the patient increases, so our research team pre-developed a miniaturized near-infrared (NIR) imaging system in advance. To improve the image quality of the acquired NIR images, this study aims to model the non-local means (NLM) algorithm, which is well known to be efficient in noise reduction, and analyze its applicability in the system. The developed NIR imaging system is based on the principle that infrared rays pass through dichroic and long-pass filters and are detected by a CMOS sensor module. The proposed NLM algorithm is modeled based on the principle of replacing the pixel from which noise is to be removed with a value that reflects the distances between surrounding pixels. After acquiring an NIR image with a central wavelength of 850 nm, the NLM algorithm was applied to segment the final vein area through histogram equalization. As a result, the coefficient of variation of the NIR image of the vein using the NLM algorithm was 0.247 on average, which was an excellent result compared to conventional filtering methods. In addition, the dice similarity coefficient value of the NLM algorithm was improved by 62.91 and 9.40%, respectively, compared to the median filter and total variation methods. In conclusion, we demonstrated that the NLM algorithm can acquire accurate segmentation of veins acquired with a NIR imaging system.

A Method for Finger Vein Recognition using a New Matching Algorithm (새로운 정합 알고리즘을 이용한 손가락 정맥 인식 방법)

  • Kim, Hee-Sung;Cho, Jun-Hee
    • Journal of KIISE:Software and Applications
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    • v.37 no.11
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    • pp.859-865
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    • 2010
  • In this paper, a new method for finger vein recognition is proposed. Researchers are recently interested in the finger vein recognition since it is a good way to avoid the forgery in finger prints recognition and the inconveniences in obtaining images of the iris for iris recognition. The vein images are processed to obtain the line shaped vein images through the local histogram equalization and a thinning process. This thinned vein images are processed for matching, using a new matching algorithm, named HS(HeeSung) matching algorithm. This algorithm yields an excellent recognition rate when it is applied to the curve-linear images processed through a thinning or an edge detection. In our experiment with the finger vein images, the recognition rate has reached up to 99.20% using this algorithm applied to 650finger vein images(130person ${\times}$ 5images each). It takes only about 60 milliseconds to match one pair of images.

Uniform Load Distribution Using Sampling-Based Cost Estimation in Parallel Join (병렬 조인에서 샘플링 기반 비용 예측 기법을 이용한 균등 부하 분산)

  • Park, Ung-Gyu
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.6
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    • pp.1468-1480
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    • 1999
  • In database systems, join operations are the most complex and time consuming ones which limit performance of such system. Many parallel join algorithms have been proposed for the systems. However, they did not consider data skew, such as attribute value skew (AVS) and join product skew (JPS). In the skewness environments, performance of framework for a uniform load distribution and an efficient parallel join algorithm using the framework to handle AVS and JPS. In our algorithm, we estimate data distributions of input and output relations of join operations using the sampling methodology and evaluate join cost for the estimated data distributions. Finally, using the histogram equalization method we distribute data among nodes to achieve good load balancing among nodes in the local joining phase. For performance comparison, we present simulation model of our algorithm and other join algorithms and present the result of some simulation experiments. The results indicate that our algorithm outperforms other algorithms in the skewed case.

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Systematic Approach to The Extraction of Effective Region for Tongue Diagnosis (설진 유효 영역 추출의 시스템적 접근 방법)

  • Kim, Keun-Ho;Do, Jun-Hyeong;Ryu, Hyun-Hee;Kim, Jong-Yeol
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.6
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    • pp.123-131
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    • 2008
  • In Oriental medicine, the status of a tongue is the important indicator to diagnose the condition of one's health like the physiological and the clinicopathological changes of internal organs in a body. A tongue diagnosis is not only convenient but also non-invasive, and therefore widely used in Oriental medicine. However, the tongue diagnosis is affected by examination circumstances like a light source, patient's posture, and doctor's condition a lot. To develop an automatic tongue diagnosis system for an objective and standardized diagnosis, segmenting a tongue region from a facial image captured and classifying tongue coating are inevitable but difficult since the colors of a tongue, lips, and skin in a mouth are similar. The proposed method includes preprocessing, over-segmenting, detecting the edge with a local minimum over a shading area from the structure of a tongue, correcting local minima or detecting the edge with the greatest color difference, selecting one edge to correspond to a tongue shape, and smoothing edges, where preprocessing consists of down-sampling to reduce computation time, histogram equalization, and edge enhancement, which produces the region of a segmented tongue. Finally, the systematic procedure separated only a tongue region from a face image with a tongue, which was obtained from a digital tongue diagnosis system. Oriental medical doctors' evaluation for the results illustrated that the segmented region excluding a non-tongue region provides important information for the accurate diagnosis. The proposed method can be used for an objective and standardized diagnosis and for an u-Healthcare system.