• Title/Summary/Keyword: Visual defect

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Defect Detection Method using Human Visual System and MMTF (MMTF와 인간지각 특성을 이용한 결함성분 추출기법)

  • Huh, Kyung-Moo;Joo, Young-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.12
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    • pp.1094-1098
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    • 2013
  • AVI (Automatic Vision Inspection) systems automatically detect defect features and measure their sizes via camera vision. Defect detection is not an easy process because of noises from various sources and optical distortion. In this paper the acquired images from a TFT panel are enhanced with the adoption of an HVS (Human Visual System). A human visual system is more sensitive on the defect area than the illumination components because it has greater sensitivity to variations of intensity. In this paper we modified an MTF (Modulation Transfer Function) in the Wavelet domain and utilized the characteristics of an HVS. The proposed algorithm flattens the inner illumination components while preserving the defect information intact.

Assessment of the Relationship between Vigabatrin and Visual Field Defect in Children (항경련제 Vigabatrin이 시야에 미치는 영향)

  • Chung, Sa Jun;Chung, Yong Hwan;Cho, Eu Hyun
    • Clinical and Experimental Pediatrics
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    • v.45 no.12
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    • pp.1546-1550
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    • 2002
  • Purpose : The authors carried out this study to determine the relationship between vigabatrin (VGB) and visual field defect.. Methods : Seventy eight patients older than 8 years who had epilepsy which had developed and been diagnosed, and were receiving add-on therapy, were the subjects of this study. If suspicious results were obtained from the initial test with the Humphrey automatic perimeter, the patient was tested again with the Goldman perimeter. Follow-up examinations were performed on these patients after 6 months. Results : In this study, five of the 78 patients had suspicious primary test results, but upon the second examination they were all found to be normal. Thus there were no patients with visual field defects. Conclusion : VGB is a drug which may cause visual field defects, but in this study no patients presented with this symptom. Instead of limiting the use of VGB due to the adverse effect of visual field defect in the initial treatment of partial seizure and infantile spasm untreatable with other medication, if used with care it may not cause serious problems. Screening for visual defect is recommended, and in patients taking VGB regular examination is necessary.

Modified Trans-Middle Temporal Gyrus Approach for Trigonal Tumor to Preserve Visual Field

  • Choi, Jeong-Wook;Jung, Shin;Jung, Tae-Young;Jang, Woo-Youl;Moon, Kyung-Sub;Kim, In-Young
    • Journal of Korean Neurosurgical Society
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    • v.50 no.6
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    • pp.538-541
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    • 2011
  • Objective : We evaluated a modified trans-middle temporal gyrus (MTG) approach with good postoperative visual preservation for patients with trigonal tumors. Methods : Three patients with a trigonal tumor were treated via the modified trans-MTG approach guided by a neuro-navigator. Modified trans-MTG approach involve the incision at the MTG within 5 mm to the superior temporal sulcus. This approach makes a proper trajectory to the trigone but also reduces the retraction injury of MTG as little as possible to prevent postoperative visual field defect. Preoperative and postoperative visual field examination using perimetry was performed to evaluate the visual field. Results : Three patients underwent surgery for lymphoma in the right trigone, meningioma in the left trigone, and focal enhancing nodule in the right paratrigonal area, respectively. In case of lymphoma, preoperative examination showed a left homonymous hemianopsia : one week later after surgery, a visual field examination was performed and revealed improvement of the visual field defect. In case of the meningioma, the preoperative examination showed no visual field defect : one month later, the visual field had no defect. In case of the enhancing nodule, preoperative visual field testing revealed a partial left homonymous hemianopsia. Visual examination within one month after surgery showed no visual field defect. All three patients treated with the modified trans-MTG approach showed no visual deterioration after surgery. Conclusion : The modified trans-MTG approach provides a safe and useful technique for trigonal tumors without postoperative visual field deterioration and affords adequate exposure of the trigonal tumor with a short trajectory.

Automatic Visual Inspection System Development for Tarpaulin's Pinholes Defect Detection (다포린 원단의 함침 자동 검출 시스템 개발)

  • O, Chun-Seok;Lee, Hyeon-Min
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.6
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    • pp.1973-1979
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    • 2000
  • Driving the need for machine vision system is growing consumer demand for quality and defect-free products. Especially it is the most important in tarpaulin's manufacturing process achieves automatically by machine vision instead of by man vision. In this paper pinholes detection is performed by using morphology algorithms. Top hat transform is one of morphology applications. This transform take high performance of defect detection in the case that unexpected changes occur in some non-uniform background. For pinholes defect, automatic visual inspection system has been developed, which was composed by a line-scan camera, illumination, a frame grabber, a motor driver and control units. This system has excellent capacity to defect pinholes to the 0.1 mm by 0.5 mm in size and to work in moving objects by maximum 20 m/min in speed.

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Local Binary Feature and Adaptive Neuro-Fuzzy based Defect Detection in Solar Wafer Surface (지역적 이진 특징과 적응 뉴로-퍼지 기반의 솔라 웨이퍼 표면 불량 검출)

  • Ko, JinSeok;Rheem, JaeYeol
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.2
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    • pp.57-61
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    • 2013
  • This paper presents adaptive neuro-fuzzy inference based defect detection method for various defect types, such as micro-crack, fingerprint and contamination, in heterogeneously textured surface of polycrystalline solar wafers. Polycrystalline solar wafer consists of various crystals so the surface of solar wafer shows heterogeneously textures. Because of this property the visual inspection of defects is very difficult. In the proposed method, we use local binary feature and fuzzy reasoning for defect detection. Experimental results show that our proposed method achieves a detection rate of 80%~100%, a missing rate of 0%~20% and an over detection (overkill) rate of 9%~21%.

A Surgical Case of Lymphocytic Hypophysitis with Progressive Visual Worsening

  • Shin, Hee-Sup;Park, Bong-Jin;Lim, Young-Jin
    • Journal of Korean Neurosurgical Society
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    • v.42 no.3
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    • pp.216-219
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    • 2007
  • Lymphocytic hypophysitis is a clinically rare disease, and it has been known to be an autoimmune disease which mainly affects pregnant women at the end of gestation or right after delivery. The authors experienced a case of lymphocytic hypophysitis in a 29-year-old pregnant woman with rapid progressing visual disturbance. Sella MRI showed a mass-like lesion of hypophysis and hypertrophy of pituitary stalk with evidences of hypopituitarism. Cesarean section was done and then TSA was performed. The pathologic diagnosis was lymphocytic hypophysitis. After TSA, visual acuity was improved and visual field defect was recovered. She was given thyroid hormone replacement therapy because of transient partial hypopituitarism for 6 months after surgery. One must consider the probability of lymphocytic hypophysitis, if there are alteration of visual acuity and visual field defect which aggravate rapidly during pregnancy due to mass effect, decreased serum hormonal levels shown in hypopituitarism and sella MRI findings of hypertrophy of pituitary stalk and enlargement of pituitary gland.

Visual Field Defect after Taking Atorvastatin/Ezetimibe, a Case Study (Atorvastatin/ezetimibe 복합제 복용 후 발생한 시야결손 부작용 사례보고)

  • Kim, Jiyoon;Lee, Kyunggyu;Kim, Junyoung;Lee, Jung-Min;Kim, Na-Young;Lee, Mo-Se;Ji, Eunhee
    • Korean Journal of Clinical Pharmacy
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    • v.29 no.2
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    • pp.133-137
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    • 2019
  • Atorvastatin is one of the most widely prescribed medications for dyslipidemia treatment. In Korea, post combined therapy with ezetimibe, a 73-year-old woman was reported by a community pharmacy to have experienced visual field defect, which recovered after drug discontinuation. She had never experienced this symptom before, and several studies have reported an association between use of statins and visual disorders such as blurred vision, diplopia, and cataract. Blockage of cholesterol accumulation, oxidative stress, or myopathy is expected to be a cause of this symptom. Naranjo scale, Korean causality assessment algorithm (Ver.2), and World Health Organization-Uppsala Monitoring Center (WHO-UMC) criteria were the three tools used to determine causality between the visual disorder and atorvastatin. The results represent 'probable', 'certain', and 'probable/likely' causality, respectively. Our results, in combination with a review of literature, indicate that ocular adverse effects are highly likely related to atorvastatin.

A case study of bilateral superior altitudinal hemianopia in a stroke patient treated with Korean Medicine (뇌졸중 후 양안의 동측 상방 수평반맹을 호소하는 환자 한의 치험 1례)

  • Choi, Jeong-Woo;Kim, Seo-Young;Kim, Ha-Ri;Shin, Hee-Yeon;Yang, Seung-Bo;Cho, Seung-Yeon;Park, Seong-Uk;Ko, Chang-Nam;Park, Jung-Mi
    • The Journal of the Society of Stroke on Korean Medicine
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    • v.20 no.1
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    • pp.43-52
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    • 2019
  • ■ Objectives The purpose is to report the case of Korean medicine in the treatment of bilateral superior altitudinal hemianopia after a stroke. ■ Methods The patient was treated with acupuncture, electroacupuncture, bee venom, and herbal medicine. The visual field defect was assessed using humphrey visual field analyzer and confrontation visual field test. ■ Results After treatment, humphrey visual field analyzer and confrontation visual field test showed improvement in field of vision ■ Conclusion This study suggested that Korean medical treatment could be an effective option for treating visual field defect after stroke.

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Development of Probability Based Defect Verification Algorithm for Automatic Visual Inspection (자동외관검사를 위한 확률기반 불량 확인 알고리즘 개발)

  • Kim, Youngheub;Ryu, Sun-Joong
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.2
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    • pp.1-8
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    • 2017
  • The visual inspection of electronic parts consists of two steps: automatic visual inspection and verification inspection. In the stage of a verification inspection, the human inspector sequentially inspects all the areas which detected in the automatic inspection. In this study, we propose an algorithm to determine the order of verification inspection by Bayes inference well known in the field of machine learning. This is a method of prioritizing a region estimated to have a high probability of defect using experience data of past inspection. This algorithm was applied to the visual inspection of ultraviolet filters to verify its effectiveness. As a result of the comparison experiment, it was confirmed that the verification inspection can be completed 30% of the conventional method by adapting proposed algorithm.

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Coating defect classification method for steel structures with vision-thermography imaging and zero-shot learning

  • Jun Lee;Kiyoung Kim;Hyeonjin Kim;Hoon Sohn
    • Smart Structures and Systems
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    • v.33 no.1
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    • pp.55-64
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    • 2024
  • This paper proposes a fusion imaging-based coating-defect classification method for steel structures that uses zero-shot learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured by an infrared (IR) camera, while photos of the coating surface are captured by a charge-coupled device (CCD) camera. The measured heat responses and visual images are then analyzed using zero-shot learning to classify the coating defects, and the estimated coating defects are visualized throughout the inspection surface of the steel structure. In contrast to older approaches to coating-defect classification that relied on visual inspection and were limited to surface defects, and older artificial neural network (ANN)-based methods that required large amounts of data for training and validation, the proposed method accurately classifies both internal and external defects and can classify coating defects for unobserved classes that are not included in the training. Additionally, the proposed model easily learns about additional classifying conditions, making it simple to add classes for problems of interest and field application. Based on the results of validation via field testing, the defect-type classification performance is improved 22.7% of accuracy by fusing visual and thermal imaging compared to using only a visual dataset. Furthermore, the classification accuracy of the proposed method on a test dataset with only trained classes is validated to be 100%. With word-embedding vectors for the labels of untrained classes, the classification accuracy of the proposed method is 86.4%.