• Title/Summary/Keyword: Dynamic range

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A Study on the Limit of Dynamic Rrange Improvement of Complementary Con-elation OTDR Caused by the Increased Measurement Cycle at Long Code Length (Complementary Correlation OTDR에서의 긴 코드 길이에 따른 측정시간 증가에 의한 Dynamic Range 증가 제한에 대한 연구)

  • 김동선;박재홍
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.11
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    • pp.19-28
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    • 2003
  • The limitation on the dynamic range improvement of the complementary correlation optical time domain reflectometer(CCOTDR) is presented. In CCOTDR, the improvement of dynamic range is function of both the averaging number of measurement cycles and the length of codes. The trade off between the averaging number and the code length restricts the improvement of the dynamic range and a very long code is not effective to improve the dynamic range. In this paper, the improvement limitation on dynamic range caused by the trade off between the averaging number and the code length is presented. For derivation of the trade off, the number of one measurement cycles employing a conventional single pulse method and employing a complementary code method are presented and compared. And the effective maximum code length is presented in addition.

Adaptive local histogram modification method for dynamic range compression of infrared images

  • Joung, Jihye
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.6
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    • pp.73-80
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    • 2019
  • In this paper, we propose an effective dynamic range compression (DRC) method of infrared images. A histogram of infrared images has narrow dynamic range compared to visible images. Hence, it is important to apply the effective DRC algorithm for high performance of an infrared image analysis. The proposed algorithm for high dynamic range divides an infrared image into the overlapped blocks and calculates Shannon's entropy of overlapped blocks. After that, we classify each block according to the value of entropy and apply adaptive histogram modification method each overlapped block. We make an intensity mapping function through result of the adaptive histogram modification method which is using standard-deviation and maximum value of histogram of classified blocks. Lastly, in order to reduce block artifact, we apply hanning window to the overlapped blocks. In experimental result, the proposed method showed better performance of dynamic range compression compared to previous algorithms.

Effect of dynamic range consumption for microholographic data storage system (마이크로 홀로그래픽 시스템에서 미디어의 소진효과)

  • Kim, Do-Hyung;Min, Cheol-Ki;Cho, Jang-Hyun;Kim, Nak-Yeong;Park, Kyoung-Su;Park, No-Cheol;Yang, Hyun-Seok;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.7 no.1
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    • pp.31-35
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    • 2011
  • In microholographic data storage system (MDSS), compact recording is required to achieve high capacity.[1] When the data is recorded, neighbor monomer is also affected by reaction at the focal point.[2,3] This unintended process caused more monomer consumption and degradation of total capacity. To avoid this extra consumption of dynamic range, it is required to define the effective dynamic range for MDSS. In this paper, we experimentally investigate the relation between dynamic range consumption and micro grating formation. Dynamic range consumption was monitored by real time read-out system. Micrograting was recorded with different consumption ratio and compared by diffraction efficiency of track direction. Finally, we define suitable dynamic range for MDSS.

Audiological Benefits in Dynamic Range Compression Hearing Aids (가청범위압축방식 보청기의 청각학적 이득에 관한 연구)

  • Heo, Seung-Deok;Kim, Lee-Suk;Jung, Dong-Keun;Ko, Do-Heung;Park, Byung-Gun
    • Speech Sciences
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    • v.11 no.2
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    • pp.19-25
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    • 2004
  • Hearing aids play an very important role in aural rehabilitation for hearing impaired person who could not be medically treated. Especially, hearing aids with dynamic range compression (level dependent frequency response: LDFR) method concentrated dynamic output range of receiver into the narrowing dynamic range of sensorineural hearing impaired person. Thus, if aided hearing threshold level is improved and uncomfortable loudness level rises, then the users of hearing aids are favored with extended dynamic range. This study aims to evaluate audiological benefits in dynamic range compression hearing aids. To achieve this, pure tone and speech audiometry were examined to 15 children and 3 adults with narrow dynamic range moderate-to-severe binaural sensorineural hearing loss.

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Extension of the Dynamic Range in the CMOS Active Pixel Sensor Using a Stacked Photodiode and Feedback Structure

  • Jo, Sung-Hyun;Lee, Hee Ho;Bae, Myunghan;Lee, Minho;Kim, Ju-Yeong;Choi, Pyung;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.22 no.4
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    • pp.256-261
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    • 2013
  • This paper presents an extension of the dynamic range in a complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) using a stacked photodiode and feedback structure. The proposed APS is composed of two additional MOSFETs and stacked P+/N-well/P-sub photodiodes as compared with a conventional APS. Using the proposed technique, the sensor can improve the spectral response and dynamic range. The spectral response is improved using an additional stacked P+/N-well photodiode, and the dynamic range is increased using the feedback structure. Although the size of the pixel is slightly larger than that of a conventional three-transistor APS, control of the dynamic range is much easier than that of the conventional methods using the feedback structure. The simulation and measurement results for the proposed APS demonstrate a wide dynamic range feature. The maximum dynamic range of the proposed sensor is greater than 103 dB. The designed circuit is fabricated by the $0.35-{\mu}m$ 2-poly 4-metal standard CMOS process, and its characteristics are evaluated.

Dynamic Range Reconstruction Algorithm for Smart Phone Camera Pulse Measurement Robust to Light Condition (조명 조건에 강건한 스마트폰 카메라 맥박 측정을 위한 다이내믹 레인지 재구성 알고리즘)

  • Park, Sang Wook;Cha, Kyoungrae
    • IEMEK Journal of Embedded Systems and Applications
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    • v.10 no.1
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    • pp.1-6
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    • 2015
  • Recently, handy pulse measurement method was introduced by using smart phone camera. However, measured values are not consistent with the variations of external light conditions, because the external light interfere with dynamic range of captured pulse image. Thus, adaptive dynamic range reconstruction algorithm is proposed to conduct pulse measurement robust to light condition. The minimum and maximum values for dynamic ranges of green and blue channels are adjusted to appropriate values for pulse measurement. In addition, sigmoid function based curve is applied to adjusted dynamic range. Experimental results show that the proposed algorithm conducts suitably dynamic range reconstruction of pulse image for the interference of external light sources.

Tone Mapping Method using Non-linear Dynamic Range Normalization for High Dynamic Range Images (HDR 영상을 위한 비선형 동적영역 정규화를 이용한 톤 매핑 기법)

  • Kim, Beom-Yong;Hwang, Bo-Hyun;Yun, Jong-Ho;Choi, Myung-Ryul
    • Proceedings of the IEEK Conference
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    • pp.851-852
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    • 2008
  • In this paper, we propose a tone mapping method using Non-linear Dynamic Range Normalization (NDRN) for High Dynamic Range (HDR) images. HDR images are not suitable for commercial display devices because dynamic range of HDR images do not match with one of Low Dynamic Range (LDR) display devices. To reproduce a tone of HDR images for LDR displays, tone mapping methods have been proposed such as local and global tone mapping. We introduce NDRN to locate mean of HDR images at the center of LDR. NDRN preserves the details for highlight and shadow. By suppressing the significant luminance change in tone mapping, naturalness of original image can be also preserved. The experimental results show that the proposed method preserves details and naturalness of original images.

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Spatial Resolution and Dynamic Range Enhancement Algorithm using Multiple Exposures (복수 노출을 이용한 공간 해상도와 다이내믹 레인지 향상 알고리즘)

  • Choi, Jong-Seong;Han, Young-Seok;Kang, Moon-Gi
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.6
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    • pp.117-124
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    • 2008
  • The approaches to overcome the limited spatial resolution and the limited dynamic range of image sensors have been studied independently. A high resolution image is reconstructed from multiple low resolution observations and a wide dynamic range image is reconstructed from differently exposed multiple low dynamic range in es based on signal processing approach. In practical situations, it is reasonable to address them in a unified context because the recorded image suffers from limitations of both spatial resolution and dynamic range. In this paper, the image acquisition process including limited spatial resolution and limited dynamic range is modelled. With the image acquisition model, the response function of the imaging system is estimated and the single image of which spatial resolution and dynamic range are simultaneously enhanced is obtained. Experimental results indicate that the proposed algorithm outperforms the conventional approaches that perform the high resolution and wide dynamic range reconstruction sequentially with respect to both objective and subjective criteria.

A Tone Mapping Method by Local Contrast and Detail Enhancement for High Dynamic Range Images

  • Kim, Beom-Yong;Hwang, Bo-Hyun;Yun, Jong-Ho;Choi, Myung-Ryul
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.741-744
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    • 2008
  • In this paper, tone mapping method by local contrast and detail enhancement for High Dynamic Range (HDR) is proposed. By applying Piecewise Dynamic Range Histogram Adjustment (PDRHA) and Detail Enhancement Volume (DEV) with decomposed layers, tone mapping is performed effectively. The experimental results show that the proposed method preserves local contrast and overall impression with naturalness of original images.

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Dynamic Range Improvement of Digital Receiver (디지털 수신기의 Dynamic Range 개선방안)

  • Hwang, Hee-Geun;Rhee, Young-Chul
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.5 no.2
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    • pp.61-67
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    • 2012
  • In this paper, In this paper, we consider a dynamic range in the frequency converter to obtain a high conversion gain and linearity while operating area proposed to broaden the design. Super-heterodyne RF Front-End style was applied to the active mixer stage, GaAs devices were used. Circuit design easy and simple forms benefit circuit is constructed in the drain mixer, passive mixer with the operating area were compared and analyzed. The simulation results of the conversion gain of 2.4dB and 0.2dBm about a gain-compression point, and showed the dynamic range of 71.9dB, when compared with passive mixers, dynamic range of approximately 6dB improvement was identified. Measurements of an approximately 2dB conversion gain and-1.0dBm of the gain-compression point, and confirmed that the active area of 71.1dB. When compared with passive mixers, dynamic range of is reduced by approximately 8dB has been improved.