• Title/Summary/Keyword: 시각적 성능

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Simulation of Sensor Measurements for Location Estimation of an Underwater Vehicle (수중 운반체 위치 추정 센서의 측정 시뮬레이션)

  • Han, Jun Hee;Ko, Nak Yong;Choi, Hyun Taek;Lee, Chong Moo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.26 no.3
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    • pp.208-217
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    • 2016
  • This paper describes a simulation method to generate sensor measurements for location estimation of an underwater robot. Field trial of a navigation method of an underwater robot takes much time and expenses and it is difficult to change the environment of the field trial as desired to test the method in various situations. Therefore, test and verification of a navigation method through simulation is inevitable for underwater environment. This paper proposes a method to generate sensor measurements of range, depth, velocity, and attitude taking the uncertainties of measurements into account through simulation. The uncertainties are Gaussian noise, outlier, and correlation between the measurement noise. Also, the method implements uncertainty in sampling time of measurements. The method is tested and verified by comparing the uncertainty parameters calculated statistically from the generated measurements with the designed uncertainty parameters. The practical feasibility of the measurement data is shown by applying the measurement data for location estimation of an underwater robot.

A Real-Time Stereoscopic Image Conversion Method Based on A Single Frame (단일 프레임 기반의 실시간 입체 영상 변환 방법)

  • Jung Jae-Sung;Cho Hwa-Hyun;Choi Myung-Ryul
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.43 no.1 s.307
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    • pp.45-52
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    • 2006
  • In this paper, a real-time stereoscopic image conversion method using a single frame from a 2-D image is proposed. The Stereoscopic image is generated by creating depth map using vortical position information and parallax processing. For a real-time processing of stereoscopic conversion and reduction of hardware complexity, it uses image sampling, object segmentation by standardizing luminance and depth map generation by boundary scan. The proposed method offers realistic 3-D effect regardless of the direction, velocity and scene conversion of the 2-D image. It offers effective stereoscopic conversion using images suitable conditions assumed in this paper such as recorded image at long distance, landscape and panorama photo because it creates different depth sense using vertical position information from a single frame. The proposed method can be applied to still image because it uses a single frame from a 2-D image. The proposed method has been evaluated using visual test and APD for comparing the stereoscopic image of the proposed method with that of MTD. It is confirmed that stereoscopic images conversed by the proposed method offers 3-D effect regardless of the direction and velocity of the 2-D image.

Design and Fabrication of 32x32 Foveated CMOS Retina Chip for Edge Detection with Local-Light Adaptation (국소 광적응 기능을 가지는 윤곽검출용 32x32 방사형 CMOS 시각칩의 설계 및 제조)

  • Park, Dae-Sik;Park, Jong-Ho;Kim, Kyung-Moon;Lee, Soo-Kyung;Kim, Hyun-Soo;Kim, Jung-Hwan;Lee, Min-Ho;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.11 no.2
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    • pp.84-92
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    • 2002
  • A $32{\times}32$ pixels foveated (linear-polar) structure retina chip with the function of local-light adaptation for edge detection has been designed and fabricated using CMOS technology. Human retina can detect a wide range of light intensity. In this study, we use the biologically-inspired visual signal processing mechanism that consists of photoreceptors, horizontal cells, and bipolar cells in order to implement the function of edge detection in the retina chip. For a local-light adaptive function, the size of receptive field is changed locally according to the input light intensity. The spatial distribution of sensing pixels in the foveated retina chip has the advantages of selective reduction of image data and good resolution in central part to carry out the elaborate image processing with still enough resolution in the outer parts. The designed chip has been fabricated using standard $0.6\;{\mu}m$ double-poly triple-metal CMOS technology and optimized using HSPICE simulator.

Develpment of Analysis and Evaluation Model for a bus Transit Route Network Design (버스 노선망 설계를 위한 평가모형 개발)

  • Han, Jong-Hak;Lee, Seung-Jae;Kim, Jong-Hyeong
    • Journal of Korean Society of Transportation
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    • v.23 no.2
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    • pp.161-172
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    • 2005
  • This study is to develop Bus Transit Route Analysis and Evaluation Model that can product the quantitative performance measures for Bus Transit Route Network Design. So far, in Korea, there are no so many models that evaluate a variety of other performance measures or service quality that are of concern to both the transit users and operator because of lower-level bus database system and transit route network analysis algorithm's limit. The BTRAEM in this research differ from the previous approach in that the BTRAEM employs a multiple path transit trip assignment model that explicitly considers the transfer and different travel time after boarding. And we develop input-output data structure and quantitative performance measure for the BTRAEM. In the numerical experimental applying BTRAEM to Mandl transit network, We got the meaningful results on performance measure of bus transit route network. In the future, we expect BTRAEM to give a good solution in real transit network.

The Accuracy Assessment of Species Classification according to Spatial Resolution of Satellite Image Dataset Based on Deep Learning Model (딥러닝 모델 기반 위성영상 데이터세트 공간 해상도에 따른 수종분류 정확도 평가)

  • Park, Jeongmook;Sim, Woodam;Kim, Kyoungmin;Lim, Joongbin;Lee, Jung-Soo
    • Korean Journal of Remote Sensing
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    • v.38 no.6_1
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    • pp.1407-1422
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    • 2022
  • This study was conducted to classify tree species and assess the classification accuracy, using SE-Inception, a classification-based deep learning model. The input images of the dataset used Worldview-3 and GeoEye-1 images, and the size of the input images was divided into 10 × 10 m, 30 × 30 m, and 50 × 50 m to compare and evaluate the accuracy of classification of tree species. The label data was divided into five tree species (Pinus densiflora, Pinus koraiensis, Larix kaempferi, Abies holophylla Maxim. and Quercus) by visually interpreting the divided image, and then labeling was performed manually. The dataset constructed a total of 2,429 images, of which about 85% was used as learning data and about 15% as verification data. As a result of classification using the deep learning model, the overall accuracy of up to 78% was achieved when using the Worldview-3 image, the accuracy of up to 84% when using the GeoEye-1 image, and the classification accuracy was high performance. In particular, Quercus showed high accuracy of more than 85% in F1 regardless of the input image size, but trees with similar spectral characteristics such as Pinus densiflora and Pinus koraiensis had many errors. Therefore, there may be limitations in extracting feature amount only with spectral information of satellite images, and classification accuracy may be improved by using images containing various pattern information such as vegetation index and Gray-Level Co-occurrence Matrix (GLCM).

A comparative study of cavitation inception of naval ship's propeller using on-board noise and vibration signals (선체 부착 소음/진동 센서를 이용한 함정 추진기 캐비테이션 초생 분석 비교 연구)

  • Hongseok Jeong;Hanshin Seol
    • The Journal of the Acoustical Society of Korea
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    • v.42 no.3
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    • pp.243-249
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    • 2023
  • The occurrence of cavitation on the propeller is directly linked to the naval ship's survivability, and it is necessary to design a propeller shape that delays the cavitation inception. However, the propeller cavitation can occur under various operating conditions, thus it is important to identify whether the propeller cavitation exists during operation as well as in the design phase. To this end, it is necessary to use noise or vibration signals on board to monitor the cavitation inception. In this study, a hydrophone and an accelerometer were installed on the ship hull right above the propeller to compare the performance of analyzing cavitation inception between acoustic and vibration signals. Also, a high speed camera was used to visually observe the occurrence of cavitation through an observation window. The measured results showed that the spectral shapes between acoustic and vibration signals were different, but the level increases at each frequency band and the overall level of the frequency band from 1 kHz to 10 kHz showed a similar tendency. The Detection of Envelope Modulation On Noise (DEMON) analysis also showed similar results for both acoustic and vibration signals, confirming that both hydrophones and accelerometers can be utilized in the analysis of cavitation inception.

Prediction of Amyloid β-Positivity with both MRI Parameters and Cognitive Function Using Machine Learning (뇌 MRI와 인지기능평가를 이용한 아밀로이드 베타 양성 예측 연구)

  • Hye Jin Park;Ji Young Lee;Jin-Ju Yang;Hee-Jin Kim;Young Seo Kim;Ji Young Kim;Yun Young Choi
    • Journal of the Korean Society of Radiology
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    • v.84 no.3
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    • pp.638-652
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    • 2023
  • Purpose To investigate the MRI markers for the prediction of amyloid β (Aβ)-positivity in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and to evaluate the differences in MRI markers between Aβ-positive (Aβ [+]) and -negative groups using the machine learning (ML) method. Materials and Methods This study included 139 patients with MCI and AD who underwent amyloid PET-CT and brain MRI. Patients were divided into Aβ (+) (n = 84) and Aβ-negative (n = 55) groups. Visual analysis was performed with the Fazekas scale of white matter hyperintensity (WMH) and cerebral microbleeds (CMB) scores. The WMH volume and regional brain volume were quantitatively measured. The multivariable logistic regression and ML using support vector machine, and logistic regression were used to identify the best MRI predictors of Aβ-positivity. Results The Fazekas scale of WMH (p = 0.02) and CMB scores (p = 0.04) were higher in Aβ (+). The volumes of hippocampus, entorhinal cortex, and precuneus were smaller in Aβ (+) (p < 0.05). The third ventricle volume was larger in Aβ (+) (p = 0.002). The logistic regression of ML showed a good accuracy (81.1%) with mini-mental state examination (MMSE) and regional brain volumes. Conclusion The application of ML using the MMSE, third ventricle, and hippocampal volume is helpful in predicting Aβ-positivity with a good accuracy.

Hybrid Tone Mapping Technique Considering Contrast and Texture Area Information for HDR Image Restoration (HDR 영상 복원을 위해 대비와 텍스쳐 영역 정보를 고려한 혼합 톤 매핑 기법)

  • Kang, Ju-Mi;Park, Dae-Jun;Jeong, Jechang
    • Journal of Broadcast Engineering
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    • v.22 no.4
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    • pp.496-508
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    • 2017
  • In this paper, we propose a Tone Mapping Operator (TMO) that preserves global contrast and precisely preserves boundary information. In order to reconstruct a High Dynamic Range (HDR) image to a Low Dynamic Range (LDR) display by using Threshold value vs. Intensity value (TVI) based on Human Visual System (HVS) and contrast value. As a result, the global contrast of the image can be preserved. In addition, by combining the boundary information detected using Guided Image Filtering (GIF) and the detected boundary information using the spatial masking of the Just Noticeable Difference (JND) model, And improved the perceived image quality of the output image. The conventional TMOs are classified into Global Tone Mapping (GTM) and Local Tone Mapping (LTM). GTM preserves global contrast, has the advantages of simple implementation and fast execution time, but it has a disadvantage in that the boundary information of the image is lost and the regional contrast is not preserved. On the other hand, the LTM preserves the local contrast and boundary information of the image well, but some areas are expressed unnatural like the occurrence of the halo artifact phenomenon in the boundary region, and the calculation complexity is higher than that of GTM. In this paper, we propose TMO which preserves global contrast and combines the merits of GTM and LTM to preserve boundary information of images. Experimental results show that the proposed tone mapping technique has superior performance in terms of cognitive quality.

A study of artificial neural network for in-situ air temperature mapping using satellite data in urban area (위성 정보를 활용한 도심 지역 기온자료 지도화를 위한 인공신경망 적용 연구)

  • Jeon, Hyunho;Jeong, Jaehwan;Cho, Seongkeun;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.55 no.11
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    • pp.855-863
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    • 2022
  • In this study, the Artificial Neural Network (ANN) was used to mapping air temperature in Seoul. MODerate resolution Imaging Spectroradiomter (MODIS) data was used as auxiliary data for mapping. For the ANN network topology optimizing, scatterplots and statistical analysis were conducted, and input-data was classified and combined that highly correlated data which surface temperature, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), time (satellite observation time, Day of year), location (latitude, hardness), and data quality (cloudness). When machine learning was conducted only with data with a high correlation with air temperature, the average values of correlation coefficient (r) and Root Mean Squared Error (RMSE) were 0.967 and 2.708℃. In addition, the performance improved as other data were added, and when all data were utilized the average values of r and RMSE were 0.9840 and 1.883℃, which showed the best performance. In the Seoul air temperature map by the ANN model, the air temperature was appropriately calculated for each pixels topographic characteristics, and it will be possible to analyze the air temperature distribution in city-level and national-level by expanding research areas and diversifying satellite data.

A Study on the Governance of U.S. Global Positioning System (미국 글로벌위성항법시스템(GPS)의 거버넌스에 관한 연구 - 한국형위성항법시스템 거버넌스를 위한 제언 -)

  • Jung, Yung-Jin
    • The Korean Journal of Air & Space Law and Policy
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    • v.35 no.3
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    • pp.127-150
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    • 2020
  • A Basic Plan for the Promotion of Space Development (hereinafter referred to as "basic plan"), which prescribes mid- and long-term policy objectives and basic direction-setting on space development every five years, is one of the matters to be deliberated by the National Space Committee. Confirmed February 2018 by the Committee, the 3rd Basic Plan has a unique matter, compared to the 2nd Basic Plan. It is to construct "Korean Positioning System(KPS)". Almost every country in the world including Korea has been relying on GPS. On the occasion of the shooting down of a Korean Air flight 007 by Soviet Russia, GPS Standard Positioning Service has been open to the world. Due to technical errors of GPS or conflict of interests between countries in international relations, however, the above Service can be interrupted at any time. Such cessation might bring extensive damage to the social, economic and security domains of every country. This is why some countries has been constructing an independent global or regional satellite navigation system: EU(Galileo), Russia(Glonass), India(NaVic), Japan(QZSS), and China(Beidou). So does South Korea. Once KPS is built, it is expected to make use of the system in various areas such as transportation, aviation, disaster, construction, defense, ocean, distribution, telecommunication, etc. For this, a pan-governmental governance is needed to be established. And this governance must be based on the law. Korea is richly experienced in developing and operating individually satellite itself, but it has little experience in the simultaneous development and operation of the satellites, ground, and users systems, such as KPS. Therefore we need to review overseas cases, in order to minimize trial and error. U.S. GPS is a classic example.