• Title/Summary/Keyword: 동적 범위

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Dynamic Range Extension of Single Image Using Deep Learning (딥러닝 기반 단일 영상의 동적범위 확장 기법)

  • Park, Hyunkook;Ji, Hyunseo;Choi, Heesu;Lee, Chul
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.1077-1079
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    • 2019
  • 일반적으로 줄어든 동적 범위를 확장하는 기법은 사진의 동적 범위를 충분히 포함하는 노출이 다른 여러 사진을 합성한다. 본 논문에서는 하나의 사진만으로 동적 범위가 확장하는 방법을 제안하였다. 하나의 사진을 딥러닝을 이용하여 구현한 네트워크가 입력 이미지의 동적 범위를 확장하도록 학습시켰다. 구현된 네트워크를 평가하기 위해 HDRNet의 결과물과 비교를 하였다. 그 결과 제안한 방법으로 얻은 이미지는 HDRNet과 비교하여 영상의 대조비가 향상되는 것을 확인하였다.

Inverse tone mapping using bilateral filter and linear mapping function (양방향 필터와 선형 사상 함수를 이용한 역 톤 매핑)

  • Kim, Dae Eun;Kim, Munchurl
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.344-346
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    • 2016
  • 본 논문에서는 양방향 필터와 (bilateral filter) 선형 사상 함수를 (linear mapping function) 이용한 역 톤매핑 (inverse tone mapping, iTMO) 알고리즘을 제안한다. 상용 HDR (high dynamic range) 디스플레이가 (display device) 보급됨에 따라 이미 존재하는 수 많은 LDR (low dynamic range) 영상을 활용하여 HDR 디스플레이에서 시청할 수 있도록 동적 범위를 (dynamic range) 확장하는 (expand) 역 톤 매핑 방법이 개발 되어야 한다. 여러 논문을 통해 다양한 역 톤 매핑 방법이 제안되어 왔는데, 대부분의 방법이 HDR 디스플레이의 동적 범위에 맞춰 LDR 영상의 동적 범위를 확장하는 것에 그쳤다. 확장하는 방법은 다양하지만, 동적 범위의 한계로 인해 LDR 영상에서 사라진 세부 사항을 (detail) 복원하는 것에는 전혀 효과적이지 않았다. 이에 본 논문에서는 LDR 영상의 동적 범위를 확장하는 것뿐만 아니라 LDR 영상에서 표현되지 못한 디테일을 복원하는 방법을 제안한다. 이를 위해 입력 영상에 양방향 필터를 적용하여 영상을 기본 계층과 (base layer) 세부 계층으로 (detail layer) 분해한 후 기본 계층에 대해서는 동적 범위에 맞게 확장하고, 세부 계층에 대해서는 디테일을 복원하기 위해 선형 사상 함수를 적용하였다. 실험을 통해서 다른 iTMO 방법에 비해 세부 사항을 효과적으로 복원할 수 있음을 확인할 수 있었다.

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A Method to Enhance Dynamic Range for Seismic Sensor Using ARMA Modelling of Low Frequency Noise and Kalman Filtering (지진계 저주파수 잡음의 ARMA 모델링 및 칼만필터를 이용한 지진계 동적범위 향상 방법)

  • Seong, Sang-Man;Lee, Byeung-Leul;Won, Jang-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.43-48
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    • 2015
  • In this study, a method to enhance the dynamic range of seismic sensor is proposed. The low frequency noise included in the measurement of seismic sensor is modelled as an ARMA(Auto Regressive Moving Average) model and the order and parameters of the model are identified through system identification method. The identified noise model is augmented into Kalmman filter which estimate seismic signal from sensor measurement. The proposed method is applied to a newly developed seismic sensor which is MEMS based 3-axis accelerometer type. The experiment show that the proposed method can enhance the dynamic range compared to the simple low pass filtering.

Analysis of Color Visualization in High Dynamic Range Image (높은 동적 범위 영상에서 색상 시각화 분석)

  • Lee, Yong-Hwan;Kim, Heung-Jun;Kim, Bong-Gi
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.705-708
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    • 2015
  • High dynamic range (HDR) imaging is a techniques used in imaging to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging. Tone mapping of HDR images for realistic display is commonly studied. However, scientific visualization of HDR image for analysis of scene luminance has much less attention. In this paper, we present and implement a simple approach for the reproduction and visualization of color information in HDR images. We attempt several simple color visualizing functions, and estimate their effectiveness through the evaluation factors with common HDR images.

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Analysis of the Linear Amplifier/ADC Interface in a Digital Microwave Receiver (디지털 마이크로파 수신기에서의 선형 증폭기와 ADC 접속 해석)

  • Lee, Min Hyouck;Kim, Sung Gon;Choi, Hee Joo;Byon, Kun Sik
    • Journal of Advanced Navigation Technology
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    • v.3 no.1
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    • pp.52-59
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    • 1999
  • Digital microwave wideband receiver including linear amplifier, analog-to-digital converter(ADC) and digital signal processor is able to analyze its performance using sensitivity and dynamic range of system. Determination of gain, third-order intermodulation products and ADC characteristics and design criteria for the linear amplifier chain is essential problem for sensitive and dynamic range. Also, if there are two signals with frequencies very close, digital signal processor must be able to separate the two signals. In this paper, we measured dynamic range as gain was changed and determined gain value for the proper sensitivity and dynamic range and high resolution spectrum estimation was used to separate two close signals.

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Maximization of Dynamic Range in Wave Digital Filter (웨이브 디지탈 필터의 동적범위 최대화)

  • 권희훈;김명기
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.12 no.4
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    • pp.373-385
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    • 1987
  • The scaled WDF should be optimized from the point of view of dynamic range. Transformer scaling method is attempted to maximize the dynamic range by equalizing the gains in the different nodes of the WDF. In this paper, the dual network and different frequencies are used to study the effects of different topology and of sampling frequency. Comparing with the unscaled WDF, the most significant observation is that the SNR is improved in the range of 7 to 35 dB in the WDF scaled by the trasnsformer scaling method. In addition, the SNR shows a continuous drop with the increase of sampling frequency, but scaling effects seem to decrease the rate at which the SNR drop.

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A Study on the Dynamic Range Performance Evaluation Method of Detector with Variation of Tube Voltage and Automatic Exposure Control (AEC) in Digital Radiography (DR) -Focused on the Dynamic Step Wedge and Histogram Evaluation (DR(Digital Radiography)에서 관전압 및 자동노출제어장치의 감도 변화에 따른 검출기의 동적 범위 성능평가 방법연구 -Dynamic Step Wedge와 히스토그램 평가를 중심으로)

  • Hwang, Jun-Ho;Choi, Ji-An;Kim, Hyun-Soo;Lee, Kyung-Bae
    • The Journal of the Korea Contents Association
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    • v.19 no.4
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    • pp.368-380
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    • 2019
  • This study proposes a method to evaluate the performance of a detector by analyzing the dynamic step wedge and histogram according to the change of the tube voltage and sensitivity when using the Automatic Exposure Control (AEC). The performance of a detector was evaluated by measuring X-ray quality, Entrance Surface Dose (ESD), tube current, dynamic range corresponding to detector sensitivities of S200, S400, S800, S1000 per tube voltage of 60, 70, 81, 90 kVp. As a results, all of the qualities satisfied the acceptance criteria, and the Entrance Surface Dose and tube current were decreased stage by stage as sensitivity was set higher. In the dynamic step wedge, the observable dynamic range has also increased as tube voltage became higher. The histogram showed the quantization separation phenomena as the tube voltage was set higher. The higher the sensitivity, the more the underflow and overflow occurred in which the amount of information on both ends of the histogram was lost. In conclusion, the deterioration in the performance of the detector was found to be insufficient to realize the change of the tube voltage and sensitivity when using the Automatic Exposure Control, and it is useful to use dynamic step wedge and histogram in evaluating detector performance evaluation.

A/D Conversion Module for Dynamic Range Expansion of Wideband Digital Receiver (광대역 디지털 수신기 동적 범위 확장을 위한 A/D 변환모듈 연구)

  • Go, Min-Ho;Kim, Hyoung-Joo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.12
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    • pp.986-991
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    • 2018
  • In this paper, an A/D conversion module was designed and fabricated to improve the dynamic range of wideband digital receivers. The A/D conversion module for expanding the dynamic range converts signals into a digital signal by branching the input signal into the normal path and the amplification path according to the input signal level. Test results of the fabricated module show that the normal path of the A/D conversion module converts an input level of -57 dBm to -12 dBm into a digital signal, and the amplification path converts an input level of -30 dBm to +12 dBm into a digital signal without distortion. This translates to an input dynamic range characteristic of 69 dB. Moreover, it is confirmed that the constant output characteristic is exhibited at an instantaneous bandwidth of 100 MHz.