• Title/Summary/Keyword: Spatial target

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A Study on the Development of New Coded Targets for a Mobile Mapping System (차량측량시스템을 위한 코드 타겟 개발에 관한 연구)

  • Eom, Woo-Hak;Kim, Byung-Guk
    • Journal of Korea Spatial Information System Society
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    • v.5 no.2 s.10
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    • pp.83-89
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    • 2003
  • In this study, a new coded targets that being suitable for a Mobile Mapping System and method of automated target recognition and coordinates determination of center point was developed, the purpose of a Mobile Mapping System is acquisition and logging data around the road for the camera calibration and the Exterior orientation of system, target installed previously and CCD cameras captured the image, target center point was observed by hands, but using coded target, target recognition and center point observation process will be automated effectively, in addition we keeped up the consistency of photo coordinates observation.

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The spatial-effect profile of visual attention in perception and memory (지각과 단기 기억 수준에 발현되는 주의 효과의 공간적 연장 패턴 비교)

  • Hyun, Joo-Seok
    • Korean Journal of Cognitive Science
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    • v.19 no.3
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    • pp.311-330
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    • 2008
  • The effect of spatial attention gradually decreases as a function of the distance between the locus of attention and a target. According to this hypothesis, we tested the spatial-effect profile of visual attention when it operates on perception and memory. Experiment 1 measured accuracy of discriminating the color of a simultaneously masked target after presenting a pre-cue to either at the target location or away from the target (perception-intensive task). Experiment 2 measured accuracy of recognizing the color of several items at and around the pre-cued location (memory-intensive task). In the perception-intensive condition, the accuracy gradually dropped as the distance between the cue and target location increases. However, in the memory-intensive condition, subjects remembered only the item at the cued location. This suggests spatial attention in a memory-intensive process would operate on object-based representations. Experiment 2 showed the object-based effect observed in Experiment 1 can be also present in perception under a special circumstance. The results indicate that spatial attention can operate on object-based representations in a memory-intensive process whereas it flexibly can operate either on location-based or object-based representations in a perception-intensive process.

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Small Target Detection Using 3-dimensional Bilateral Filter (3차원 양방향 필터를 이용한 소형 표적 검출)

  • Bae, Tae-Wuk
    • Journal of Korea Multimedia Society
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    • v.16 no.6
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    • pp.746-755
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    • 2013
  • This paper presents a three dimensional bilateral filter detecting target trajectory, extracting spatial target information using two dimensional bilateral filter and temporal target information using one dimensional bilateral filter. In order to discriminate edge pixel with flat background and target region spatially and temporally, spatial and temporal variance are used for an image and temporal profile. With this procedure, background and background profile are predicted without original target through two dimensional and one dimensional bilateral filter. Finally, using spatially predicted background and temporally predicted background profile, small target can be detected. For comparison of existing target detection methods and the proposed method, the receiver operating characteristics (ROC) is used in experimental results. Experimental results show that the proposed method has superior target detection rate and lower false alarm rate.

Human's Spatial Cognition Using Auditory Stimulation

  • Yu, M.;Park, Y.G.;Jeong, S.H.;Chong, W.S.;Kwon, T.K.;Hong, C.U.;Kim, N.G.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.202-205
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    • 2004
  • This paper represents the role of pinna in localizing target direction. Specially, this paper described what is the role of right-side pinna versus left-side pinna. In this experiment, one side of the pinna function was distorted intentionally by inserting a short tube on the ear canal. The localization error caused by right and left side pinna distortion was investigated. Since a laser pointer showed much less error (0.5%) in localizing target position than FASTRAK (30%) that has been generally used, it was used for the pointing task. It was found that harmonic components were not essential for the auditory target localization, however, non-harmonic nearby frequency components were more important to localize target direction of sound. We have found that the right pinna is one of the most important functions in localizing target direction and pure tone with only one frequency component is confusing for localization.

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A Study on Optimal Hydrophone Arrangement for The Direction Finding of High Speed Moving Target in Underwater (수중에서 고속 기동하는 표적의 방위 탐지를 위한 최적의 청음기 배치 연구)

  • Han, Min-Su;Choi, Jae-Yong;Kang, Dong-Seok;Son, Kweon;Lee, Phil-ho
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.3
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    • pp.369-375
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    • 2017
  • One of good DF(Direction Finding) methods is based on TDOA(Time Difference of Arrival) estimation when finding underwater moving target. For small DF error, high time resolution A/D(Analog-to-digital) conversion board and long baseline are needed. But the result of sea trial about close-range and high speed moving target, spatial correlation coefficient and appeared poor properties below 0.3 when hydrophone arrangement are separated over 6 ${\lambda}$ because of underwater fading channel. And we also find out that the distance between hydrophone should be under 4 ${\lambda}$ apart to take advantage of spatial correlation coefficient gain and performance of DF in underwater moving channel environments.

The Effect of Spatial Attention in Hangul Word Recognition: Depending on Visual Factors (한글 단어 재인에서 시각적 요인에 따른 공간주의의 영향)

  • Ko Eun Lee;Hye-Won Lee
    • Korean Journal of Cognitive Science
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    • v.34 no.1
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    • pp.1-20
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    • 2023
  • In this study, we examined the effects of spatial attention in Hangul word recognition depending on visual factors. The visual complexity of words (Experiment 1) and contrast (Experiment 2) were manipulated to examine whether the effect of spatial attention differs depending on visual quality. Participants responded to words with and without codas in experiment 1 and words in high-contrast and low-contrast conditions in experiment 2. The effects of spatial attention were investigated by calculating the difference in performance between the condition where spatial cues were given at the target location (valid trial) and the condition where the spatial cues were not given at the target location (invalid trial) as the cuing effects. As a result, the cuing effects were similar depending on the complexity of the words. It indicates that the effects of spatial attention were not different across the visual complexity conditions. The cuing effects were greater in the low-contrast condition than in the high-contrast condition. The greater effect of spatial attention when the contrast is low was explained as a mechanism of signal enhancement.

The Intuitive Change of Virtual Wand Style in Spatial Sketch System (가상 완드 스타일의 직관적인 변형을 지원하는 공간 스케치 시스템)

  • Nam, Sang-Hun;Chai, Young-Ho
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.56-61
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    • 2009
  • According to the target object for designer to sketch, an effective style or shape of input device can be defined differently. The general spatial sketching system that support various types of wand assist sketching effectively as changing suitable wand shape to the part of a target object. We suggest the idea of changing wand style by altering the posture of a 3D wand. This allows a designer to work in an intuitive way without being interrupted by complicated menus. We implement the various wand styles to the spatial sketching system with cubic-based drawing technique.

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Effects of JPEG Compression on Joint Transform Correlator

  • Widjaja, Joewono;Suripon, Ubon
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1662-1665
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    • 2004
  • A real-time joint transform correlator by using JPEG-compressed reference images is proposed as practical solution to storage problem and improvement of processing time of automatic target recognition system [1]. Effects of compression on recognition performance of join transform correlator are quantitatively investigated under situations where the target is suffered from noise and has contrast difference with respect to the reference. Two images with different spatial-frequency contents and contrast were used as the test scenes. The simulation results show that, the recognition performance of joint transform correlator by using the compressed reference images with high spatial-frequency components is more sensitive to noise and contrast difference than the low spatial-frequency image.

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SAR RETURN SIGNAL SYNTHESIS IN TIME-SPATIAL DOMAIN

  • Shin Dongseok;Kim Moon-Gyu;Kwak Sunghee
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.729-732
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    • 2005
  • This paper describes a time-spatial domain model for simulating raw data acquisition of space-borne SAR system. The position, velocity and attitude information of the platform at a certain time instance is used for deriving sensor-target model. Ground target is modelled by a set of point scatters with reflectivity and two-dimensional ground coordinates. The signal received by SAR is calculated for each slow and fast time instance by integrating the reflectivity and phase values from all target point scatters. Different from frequency domain simulation algorithms, the proposed time domain algorithm can provide fully physical modelling of SAR raw data simulation without any assumptions or approximations.

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A search mechanism for moving objects in a spatial database (공간 데이타베이스에서 이동 객체의 탐색기법)

  • 유병구;황수찬;백중환
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.35C no.1
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    • pp.25-33
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    • 1998
  • This paepr presents an algorithm for searching an object in a fast way which contains a continuous moving object in multi-dimensional spatical databases. This algorithm improves the search method of R-tree for the case that a target object is continuously moving in a spatial database. It starts the searching from the current node instead of the root of R-tree. Thus, the algorithm will find the target object from the entries of current node or sibling nodes in the most cases. The performance analysis shows that it is more efficient than the existing algorithm for R-tree when search windows or target objects are continuously moving.

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