• Title/Summary/Keyword: False Region

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An automatic detection method for lung nodules based on multi-scale enhancement filters and 3D shape features

  • Hao, Rui;Qiang, Yan;Liao, Xiaolei;Yan, Xiaofei;Ji, Guohua
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.1
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    • pp.347-370
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    • 2019
  • In the computer-aided detection (CAD) system of pulmonary nodules, a high false positive rate is common because the density and the computed tomography (CT) values of the vessel and the nodule in the CT images are similar, which affects the detection accuracy of pulmonary nodules. In this paper, a method of automatic detection of pulmonary nodules based on multi-scale enhancement filters and 3D shape features is proposed. The method uses an iterative threshold and a region growing algorithm to segment lung parenchyma. Two types of multi-scale enhancement filters are constructed to enhance the images of nodules and blood vessels in 3D lung images, and most of the blood vessel images in the nodular images are removed to obtain a suspected nodule image. An 18 neighborhood region growing algorithm is then used to extract the lung nodules. A new pulmonary nodules feature descriptor is proposed, and the features of the suspected nodules are extracted. A support vector machine (SVM) classifier is used to classify the pulmonary nodules. The experimental results show that our method can effectively detect pulmonary nodules and reduce false positive rates, and the feature descriptor proposed in this paper is valid which can be used to distinguish between nodules and blood vessels.

Closely Spaced Target Detection using Intensity Sorting-based Context Awareness

  • Kim, Sungho;Won, Jin-Ju
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1839-1845
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    • 2016
  • Detecting remote targets is important to active protection system (APS) or infrared search and track (IRST) applications. In normal situation, the well-known constant false alarm rate (CFAR) detector works properly. However, decoys in APS or closely spaced targets in IRST degrade the detection capability by increasing background noise level in the CFAR detector. This paper presents a context aware CFAR detector by the intensity sorting and selection of background region to reduce the effect of neighboring targets that lead to incorrect estimation of background statistics. The existence of neighboring targets can be recognized by intensity sorting where neighboring targets usually show highest ranks. The proposed background statistics (mean, standard deviation) estimation method from median local pixels can be aware of the background context and reduce the effects of the neighboring targets, which increase the signal-to-clutter ratio. The experimental results on the synthetic APS sequence, real adjacent target sequence, and remote pedestrian sequence validated that the proposed method produced an enhanced detection rate with the same false alarm rate compared with the hysteresis-CFAR (H-CFAR) detection.

Two Cases of False Cord Schwannoma Treated with Transoral Laser Resection (가성대에 발생한 신경초종의 경구강 레이저 절제술 치험 2례)

  • Kim, Young-Rok;Kim, Sung-Won;Hong, Jong-Chul;Lee, Bong-Ju;Lee, Kang-Dae
    • Korean Journal of Head & Neck Oncology
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    • v.23 no.1
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    • pp.58-62
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    • 2007
  • Schwannoma is a benign well-encapsulated tumors arising from the sheath of Schwann cell of the peripheral motors, sensory, and cranial nerves, but not from the optic and olfactory nerves. Since it is relatively common in the head and neck region, it should be included in the differential diagnosis of head and neck tumor. However, reports of laryngeal involvement have rarely appeared in the literature. We have experienced a 50-year old woman and 39-year old woman with history of progressive voice change. We recognized a benign mass at the false cord area with the telelaryngoscope and CT. The tumors were successfully removed by transoral CO2 laser resection without tracheotomy.

Cloud-Type Classification by Two-Layered Fuzzy Logic

  • Kim, Kwang Baek
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.13 no.1
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    • pp.67-72
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    • 2013
  • Cloud detection and analysis from satellite images has been a topic of research in many atmospheric and environmental studies; however, it still is a challenging task for many reasons. In this paper, we propose a new method for cloud-type classification using fuzzy logic. Knowing that visible-light images of clouds contain thickness related information, while infrared images haves height-related information, we propose a two-layered fuzzy logic based on the input source to provide us with a relatively clear-cut threshold in classification. Traditional noise-removal methods that use reflection/release characteristics of infrared images often produce false positive cloud areas, such as fog thereby it negatively affecting the classification accuracy. In this study, we used the color information from source images to extract the region of interest while avoiding false positives. The structure of fuzzy inference was also changed, because we utilized three types of source images: visible-light, infrared, and near-infrared images. When a cloud appears in both the visible-light image and the infrared image, the fuzzy membership function has a different form. Therefore we designed two sets of fuzzy inference rules and related classification rules. In our experiment, the proposed method was verified to be efficient and more accurate than the previous fuzzy logic attempt that used infrared image features.

Reversible DNA Watermarking Technique Using Histogram Shifting for Bio-Security (바이오 정보보호 위한 히스토그램 쉬프팅 기반 가역성 DNA 워터마킹 기법)

  • Lee, Suk-Hwan;Kwon, Seong-Geun;Lee, Eung-Joo;Kwon, Ki-Ryong
    • Journal of Korea Multimedia Society
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    • v.20 no.2
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    • pp.244-253
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    • 2017
  • Reversible DNA watermarking is capable of continuous DNA storage and forgery prevention, and has the advantage of being able to analyze biological mutation processes by external watermarking by iterative process of concealment and restoration. In this paper, we propose a reversible DNA watermarking method based on histogram multiple shifting of noncoding DNA sequence that can prevent false start codon, maintain original sequence length, maintain high watermark capacity without biologic mutation. The proposed method transforms the non-coding region DNA sequence to the n-th code coefficients and embeds the multiple bits of the n-th code coefficients by the non-recursive histogram multiple shifting method. The multi-bit embedding process prevents the false start codon generation through comparison search between adjacent concealed nucleotide sequences. From the experimental results, it was confirmed that the proposed method has higher watermark capacity of 0.004-0.382 bpn than the conventional method and has higher watermark capacity than the additional data. Also, it was confirmed that false start codon was not generated unlike the conventional method.

Analysis of MX-TM CFAR Processors in Radar Detection (레이다 검파에서의 MX-TM CFAR 처리기들에 대한 성능 분석)

  • 김재곤;조규홍;김응태;이동윤;송익호;김형명
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1991.10a
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    • pp.92-95
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    • 1991
  • Constant false alarm rate(CFAR) processors are useful for detecting radar targets in background for which all parameters in the statistical distribution are not known and may be nonstationary. The well known "cell averging" (CA) CFAR processor is known to yield best performance in homogeneous case, but exhibits severe performance in the presence of an interfering target in the reference window or/and in the region of clutter edges. The "order statistics"(OS) CFAR processor is known to have a good performance above two nonhomogeneous cases. The modified OS-CFAR processor, known as "trimmed mean"(TM) CFAR processor performs somewhat better than the OS-CFAR processor by judiciously trimming the ordered samples. This paper proposes and analyzes the performance of a new CFAR processor called the "maximum trimmed mean"(MX-TM) CFAR processor combining the "greatest of"(GO) CFAR and TM-CFAR processors. The MAX operation is included to control false alarms at clutter edges. Our analyses show that the proposed CFAR processor has similar performance TM- and OS-CFAR processors in homogeneous case and in the precence of interfering targets, but can control the false rate in clutter edges. Simulation results are presented to demonstrate the qualitative effects of various CFAR processors in nonhomogeneous clutter environments.

A Study on the protection of false alarm in the UV/IR flame detector (불꽃 감지기에서 오동작 방지에 관한 연구)

  • Lim, Byung-Hyun;Park, Sung-Jin;Lim, Jong-Yeon;Hwang, Jong-Sun;Kim, Young-Min
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.209-212
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    • 2001
  • A flame detector responds either to radiant energy visible to the human eye or outside the range of human vision. Such a detector is sensitive to glowing embers, coals, or flames which radiate energy of sufficient intensity and spectral quality to actuate the alarm. An infra-red detectors can respond to the total IR component of the flame alone or in combination with flame flicker in the frequency range of 5 to 30 Hz. A major problem in the use of infrared detectors receiving total IR radiation is the possible interference of solar radiation in the infrared region. When detectors are located in places shielded from the sun, such as vaults, filtering or shielding the unit from the sun's rays is unnecessary. In this study, we proposed method for redue a false alarm with using filtering & sensor technology for distinguish of causes of raise a false alarm and pure flame.

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Translation- and Rotation-Invariant Fingerprint Authentication Based on Gabor Features (Gabor 특징에 기반한 이동 및 회전 불변 지문인증)

  • 김종화;조상현;성효경;최홍문
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.901-904
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    • 2000
  • A direct authentication from gray-scale image, instead of the conventional multi-step preprocessing, is proposed using Gabor filter-based features from the gray-scale fingerprint around core point. The core point is located as a reference point for the translation invariant matching. And its principal symmetry axis is detected for the rotation invariant matching from its neighboring region centered at the core point. And then fingerprint is divided into non-overlapping blocks with respect to the core point and features are directly extracted form the blocked gray level fingerprint using Gabor filter. The proposed fingerprint authentication is based on the Euclidean distance between the corresponding Gabor features of the input and the template fingerprints. Experiments are conducted on 300${\times}$300 fingerprints obtained from a CMOS sensor with 500 dpi resolution, and the proposed method could lower the False Reject Rate(FRR) to 18.2% under False Acceptance Rate(FAR) of 0%.

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The Surface Sidelobe Clutter and the False Alarm Probability of Target Detection for the HPRF Waveform of the Microwave Seeker (마이크로파 탐색기의 HPRF 파형에 대한 지표면 부엽클러터와 표적탐지 오류 확률)

  • Kim, Tae-Hyung;Yi, Jae-Woong;Byun, Young-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.4C
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    • pp.476-483
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    • 2009
  • Tracking and detecting targets by the microwave seeker is affected by the clutter reflecting from the earth's surface. In order to detect retreating targets in look-down scenario, which appear in the sidelobe clutter (SLC) region, in the microwave seeker of high pulse repetition frequency (HPRF) mode, it is necessary to understand statistical characteristics of the surface SLC. Statistical analysis of SLC has been conducted for several kinds of the surface using data obtained by the captive flight test of the microwave seeker in the HPRF mode. The probability density function (PDF) fitting is conducted for several kinds and conditions of the surface. PDFs and PDF parameters, which best describe statistical distribution of the SLC power, are estimated. By using the estimated PDFs and PDF parameters, analyses for setting the target-detection thresholds, which give a desired level of target-detection false alarm probability, are made. These analysis materials for statistical characteristics of SLC power and the target-detection threshold can be used in various fields, such as development of a target-detection method, the constant false alarm rate processing.

Is the diagnosis of calcified laryngeal cartilages on panoramic radiographs possible?

  • Cagirankaya, Leyla Berna;Akkaya, Nursel;Akcicek, Gokcen;Dogru, Hatice Boyacioglu
    • Imaging Science in Dentistry
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    • v.48 no.2
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    • pp.121-125
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    • 2018
  • Purpose: Detecting laryngeal cartilages (triticeous and thyroid cartilages) on panoramic radiographs is important because they may be confused with carotid artery calcifications in the bifurcation region, which are a risk factor for stroke. This study assessed the efficiency of panoramic radiography in the diagnosis of calcified laryngeal cartilages using cone-beam computed tomography (CBCT) as the reference standard. Materials and Methods: A total of 312 regions(142 bilateral, 10 left, 18 right) in 170 patients(140 males, 30 females) were examined. Panoramic radiographs were examined by an oral and maxillofacial radiologist with 11 years of experience. CBCT scans were reviewed by 2 other oral and maxillofacial radiologists. The kappa coefficient(${\kappa}$) was calculated to determine the level of intra-observer agreement and to determine the level of agreement between the 2 methods. Diagnostic indicators(sensitivity, specificity, accuracy, and false positive and false negative rates) were also calculated. P values <.05 were considered to indicate statistical significance. Results: Eighty-two images were re-examined to determine the intra-observer agreement level, and the kappa coefficient was calculated as 0.709 (P<.05). Statistically significant and acceptable agreement was found between the panoramic and CBCT images (${\kappa}=0.684$ and P<.05). The sensitivity, specificity, diagnostic accuracy rate, the false positive rate, and the false negative rate of the panoramic radiographs were 85.4%, 83.5%, 84.6%, 16.5%, and 14.6%, respectively. Conclusion: In most cases, calcified laryngeal cartilages could be diagnosed on panoramic radiographs. However, due to variation in the calcifications, diagnosis may be difficult.