• 제목/요약/키워드: Image size

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고압환경에서 이미지 프로세싱 기법을 이용한 액적크기 측정 (Drop Size Measurement using Image Processing Method under High Ambient Pressure Condition)

  • 임병직;길태옥;정기훈;윤영빈
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2003년도 추계학술대회 논문집
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    • pp.111-114
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    • 2003
  • Drop size is one of the most important parameters which are control the performance of the engine using liquid fuel/oxidizer and drop formation is mainly controlled by aerodynamic force caused by ambient gas. Because of this, empirical data and correlation acquired under standard ambient condition are not valid. So experiments under high ambient pressure condition to measure the drop size using image processing method And find the empirical correlation between SMD and chamber pressure(density), injection velocity.

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드론 영상으로부터 월동 작물 분류를 위한 의미론적 분할 딥러닝 모델 학습 최적 공간 해상도와 영상 크기 선정 (The Optimal GSD and Image Size for Deep Learning Semantic Segmentation Training of Drone Images of Winter Vegetables)

  • 정동기;이임평
    • 대한원격탐사학회지
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    • 제37권6_1호
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    • pp.1573-1587
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    • 2021
  • 드론 영상은 위성이나 항공 영상보다 공간 해상도가 수배 혹은 수십 배가 높은 초고해상도 영상이다. 따라서 드론 영상 기반의 원격탐사는 영상에서 추출하고자 하는 객체의 수준과 처리해야 하는 데이터의 양이 전통적인 원격탐사와 다른 양상을 보인다. 또한, 적용되는 딥러닝(deep learning) 모델의 특성에 따라 모델 훈련에 사용되는 최적의 데이터의 축척과 크기가 달라질 수밖에 없다. 하지만 대부분 연구가 찾고자 하는 객체의 크기, 축척을 반영하는 영상의 공간 해상도, 영상의 크기 등을 고려하지 않고, 관성적으로 적용하고자 하는 모델에서 기존에 사용했던 데이터 명세를 그대로 적용하는 경우가 많다. 본 연구에서는 드론 영상의 공간 해상도, 영상 크기가 6가지 월동채소의 의미론적 분할(semantic segmentation) 딥러닝 모델의 정확도와 훈련 시간에 미치는 영향을 실험 통해 정량적으로 분석하였다. 실험 결과 6가지 월동채소 분할의 평균 정확도는 공간 해상도가 증가함에 따라 증가하지만, 개별 작물에 따라 증가율과 수렴하는 구간이 다르고, 동일 해상도에서 영상의 크기에 따라 정확도와 시간에 큰 차이가 있음을 발견하였다. 특히 각 작물에 따라 최적의 해상도와 영상의 크기가 다름을 알 수 있었다. 연구성과는 향후 드론 영상 데이터를 이용한 월동채소 분할 모델을 개발할 때, 드론 영상의 촬영과 학습 데이터의 제작 효율성 확보를 위한 자료로 활용할 수 있을 것이다.

블록단위의 프래탈 근사화를 이용한 영상코딩 (Image Coding by Block Based Fractal Approximation)

  • 정현민;김영규;윤택현;강현철;이병래;박규태
    • 전자공학회논문지B
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    • 제31B권2호
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    • pp.45-55
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    • 1994
  • In this paper, a block based image approximation technique using the Self Affine System(SAS) from the fractal theory is suggested. Each block of an image is divided into 4 tiles and 4 affine mapping coefficients are found for each tile. To find the affine mapping cefficients that minimize the error between the affine transformed image block and the reconstructed image block, the matrix euation is solved by setting each partial differential coefficients to aero. And to ensure the convergence of coding block. 4 uniformly partitioned affine transformation is applied. Variable block size technique is employed in order to applynatural image reconstruction property of fractal image coding. Large blocks are used for encoding smooth backgrounds to yield high compression efficiency and texture and edge blocks are divided into smaller blocks to preserve the block detail. Affine mapping coefficinets are found for each block having 16$\times$16, 8$\times$8 or 4$\times$4 size. Each block is classified as shade, texture or edge. Average gray level is transmitted for shade bolcks, and coefficients are found for texture and edge blocks. Coefficients are quantized and only 16 bytes per block are transmitted. Using the proposed algorithm, the computational load increases linearly in proportion to image size. PSNR of 31.58dB is obtained as the result using 512$\times$512, 8 bits per pixel Lena image.

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청소년 대상 신체상 증진 프로그램의 효과에 대한 체계적 문헌 고찰 및 메타분석 (The Effects of Programs on Body-Image Improvement in Adolescents: A Systematic Review and Meta-Analysis)

  • 윤현정;서경산;한달롱
    • 대한간호학회지
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    • 제51권5호
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    • pp.597-616
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    • 2021
  • Purpose: This study's objective was to investigate the effects of programs that improve adolescents' body image, using a systematic review and meta-analysis. Methods: A literature search was performed in eleven electronic databases, using preferred reporting items for systematic reviews and meta-analysis guidelines. Population characteristics, contents of the programs, and measured outcomes were systematically reviewed from 21 selected studies. To estimate the size of the effects, meta-analysis was conducted using Comprehensive Meta-Analysis software. Results: The contents of the programs that aimed to improve body image included physical, psychological, interpersonal, and sociocultural interventions. Sixteen studies were meta-analyzed to estimate the effect size of body-image improvement programs. Results showed that the program for body-image improvement had significant effects on body satisfaction (effect size [ES] = 0.56, 95% confidence interval [CI] = 0.23 to 0.89), and body dissatisfaction (ES = - 0.15, 95% CI = - 0.23 to - 0.08). Conclusion: The program for body image improvement in adolescents includes a combination of physical, psychological, interpersonal relationship, and socio-cultural dimensions. The program that seeks to improve body image appears to be effective at increasing body satisfaction, and at reducing body dissatisfaction in adolescents. Thus, it is necessary to develop and apply multidimensional programs for adolescents to have a positive body image.

초등학교 4학년 어린이에서 비만도에 따른 신체상과 식습관 (4th-grade elementary-school children's body image and dietary habits according to body mass index)

  • 심유진;양윤경
    • Journal of Nutrition and Health
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    • 제47권4호
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    • pp.287-299
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    • 2014
  • 초등학교 4학년 아동 134명을 대상으로 신체상 및 신체상의 인지도와 만족도를 조사하고 식습관과 영양상태와의 관련성을 분석하였다. 희망하는 신체상에는 성별에 의한 차이가 존재하였는데 남학생에 비하여 여학생의 희망 신체상이 더 날씬한 모습이었으며, 정상체중의 남학생과 달리 과체중 및 비만 남학생, 정상체중 여학생, 과체중 및 비만 여학생은 자신의 현재 신체상에 비해 희망하는 신체상이 더 날씬한 모습인 것으로 나타났다. 정상체중군과 달리 과체중 및 비만군의 거의 대부분은 희망 신체상보다 자신의 신체상이 큰 신체상 불만족의 상태였다. 희망 신체상보다 자신의 신체상이 큰 신체상 불만족은 상대적으로 낮은 식습관 점수와 관련되어 있었는데 특히 규칙적인 식생활과 낮은 일일 식사 빈도 및 낮은 채소의 섭취 빈도와 관련되어 있는 것으로 나타났다. 정상체중군에 비하여 많은 수의 과체중 및 비만군은 현재 자신의 신체크기를 실제 비만도보다 낮게 인지하는 신체상 과소평가의 상태였다. 신체상 과소평가군은 정확한 인지군에 비해 아침식사의 빈도와 식사시간의 규칙성이 낮았고 외식이나 배달음식의 이용 빈도가 높은 등 상대적으로 좋지 않은 식습관을 가지고 있었으며, 낮은 단백질 섭취 수준과 높은 지질 섭취 수준 및 낮은 식이섬유와 칼슘 섭취와 관련되어 있었다. 결론적으로 초등학교 4학년 아동에서 신체상은 성별과 비만도에 따른 차이가 있었으며 식습관 및 영양섭취와도 관련되어 있었다. 청소년기 이후의 바람직한 식생활과 비만의 예방 및 정신적, 육체적으로 건강한 삶을 위해서는 신체상이 형성되는 아동기에 자신의 신체에 대한 만족도를 높이고 신체상을 정확하게 인지하려는 시도가 이루어져야 할 것이다.

입원한 조현병 환자의 신체이미지 왜곡 (Body Image Distortion among Inpatients with Schizophrenia)

  • 김성진;문석우;김대호
    • 생물정신의학
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    • 제19권4호
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    • pp.211-218
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    • 2012
  • Objectives Body image distortion is found in eating disorder and obesity and there are some evidence that schizophrenia is associated with body image distortion. This study sought to find whether schizophrenic patients report more body image distortion than healthy individuals and whether it is related with symptomatology. Methods A total of 88 inpatients with schizophrenia and 88 healthy controls were recruited. Weight, height, and body image accuracy were assessed in all participants, and assessment of mood, psychotic symptom severity and self-esteem, and personal and social performance scale were conducted. Results The patients with schizophrenia had higher Body Mass Index (p < 0. 001) and underestimated their body size more than controls (26.14% vs. 5.13%, p < 0.001). Multiple regression analysis showed that lower depressive symptoms and higher scores of general psychopathology predicted underestimation of body size. Conclusion Weight gain and metabolic syndrome are common adverse events of pharmacological treatment of schizophrenia. Thus, underestimation of body size among patients with schizophrenia may interfere with effort to lose weight or seek weight reduction programs. Clinicians need to consider possible unterestimation of underestimation of body size in patients whose general symptomatology is severe.

Development of the Korean Handwriting Assessment for Children Using Digital Image Processing

  • Lee, Cho Hee;Kim, Eun Bin;Lee, Onseok;Kim, Eun Young
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권8호
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    • pp.4241-4254
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    • 2019
  • The efficiency and accuracy of handwriting measurement could be improved by adopting digital image processing. This study developed a computer-based Korean Handwriting Assessment tool. Second graders participated in this study by performing writing tasks of consonants, vowels, words, and sentences. We extracted boundary parameters for each letter using digital image processing and calculated the variables of size, size coefficient of variation (CV), misalignment, inter-letter space, inter-word space, and ratio of inter-letter space to inter-word space. Children were also administered traditional handwriting and visuomotor tests. Digital variables from image processing were correlated with these previous tests. Using these correlations, we established a three-point scoring system that computed test scores for each variable. We analyzed inter-rater reliability between the computer rater and human rater and test-retest reliability between the first and second performances. The validity was examined by analyzing the relationship between the Korean Handwriting Assessment and previous handwriting and visuomotor tests. We suggested the Korean Handwriting Assessment to measure size, size consistency, misalignment, inter-letter space, inter-word space, and space ratio using digital image processing. This Korean Handwriting Assessment tool proved to have reliability and validity. It is expected to be useful for assessing children's handwriting.

영상 처리 기법에서 곡률을 이용한 입경 측정 알고리듬의 개발 (Development of Image Processing Algorithm Using Boundary Curvature Information in Particle Size Measurement)

  • 김유동;이상용;김상수
    • 대한기계학회논문집B
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    • 제26권10호
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    • pp.1445-1450
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    • 2002
  • In the present study, a new pattern recognition algorithm was proposed to size spray particles using the boundary curvature information. Conceptually, this algorithm has an advantage over the others because it can identify the particle size and shape simultaneously, and also can separate the overlapped particles more effectively. Curvature of a boundary was obtained from the change of the slopes of two neighboring segments at the corresponding part. The algorithm developed in this study was tested by using an artificially prepared image of a group of spherical particles which were either isolated or overlapped. Particle sizes obtained from the measured curvatures agreed well with the true values. By detecting abrupt changes of the curvature along the image boundary, the element particles could be separated out from their overlapped images successfully.

DETERMINATION OF USER DISTRIBUTION IMAGE SIZE AND POSITION OF EACH OBSERVATION AREA OF METEOROLOGICAL IMAGER IN COMS

  • Seo, Jeong-Soo;Seo, Seok-Bae;Kim, Eun-Kyou;Jung, Sung-Chul
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.228-231
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    • 2006
  • In this paper, requirements of Meteorological Administration about Meteorological Imager (MI) of Communications, Ocean and Meteorological Satellite (COMS) is analyzed for the design of COMS ground station and according to the analysis results, the distribution image size of each observation area suitable for satellite Field Of View (FOV) stated at the requirements of meteorological administration is determined and the precise satellite FOV and the size of distribution image is calculated on the basis of the image size of the determined observation area. The results in this paper were applied to the detailed design for COMS ground station and also are expected to be used for the future observation scheduling and the scheduling of distribution of user data.

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A Study on the Automatic Inspection System using Invariant Moments Algorithm with the Change of Size and Rotation

  • 이용중
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 추계학술대회
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    • pp.164-169
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    • 2003
  • The purpose of this study is to develop a practical image inspect ion system that could recognize it correctly, endowing flexibility to the productive field, although the same object for work will be changed in the size and rotated. In this experiment, it selected a fighter, rotating the direction from 30$^{\circ}$ to 45 simultaneously while changing the size from 1/4 to 1/16, as an object inspection without using another hardware for exclusive image processing. The invariant moments, Hu has suggested, was used as feature vector moment descriptor. As a result of the experiment, the image inspect ion system developed from this research was operated in real-time regardless of the chance of size and rotation for the object inspection, and it maintained the correspondent rates steadily above from 94% to 96%. Accordingly, it is considered as the flexibility can be considerably endowed to the factory automat ion when the image inspect ion system developed from this research is applied to the product ive field.

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