• 대한전자공학회논문지SD
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• 제40권11호
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• pp.19-28
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• 2003

CCOTDR (complementary correlation optical time domain reflectometer)의 dynamic range는 사용된 코드의 길이와 평균 횟수에 따라 증가한다. OTDR의 전체 측정 시간이 제한된 경우에는 코드 길이를 늘이게 되면 평균 횟수를 줄여야 한다. 이와 같은 관계 때문에 코드 길이가 일정 이상 증가하면 dynamic range의 증가 정도가 어느 이상 커지지 않는다. 본 논문에서는 전체 측정 시간이 제한된 경우에 단일 펄스를 사용한 측정 방법에서 1회 측정에 걸리는 시간과 코드를 사용한 측정 방법에서 1회 측정에 걸리는 시간을 비교하였다. 이를 바탕으로 코드를 길게 해서 dynamic range를 개선시기는 데에 한계가 있음을 보였고, 길이가 짧으면서 최대 dynamic range를 달성할 수 있는 코드 길이를 제시하였다.

• 음성과학
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• 제11권2호
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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.

• 정보저장시스템학회논문집
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• 제7권1호
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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.

• 한국컴퓨터정보학회논문지
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• 제24권6호
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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.

• 센서학회지
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• 제22권4호
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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.

• 대한임베디드공학회논문지
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• 제10권1호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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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.

• 대한전자공학회논문지SP
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• 제45권6호
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• pp.117-124
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• 2008

이미지 센서의 물리적 한계 가운데 공간 해상도의 제약과 다이내믹 레인지의 제약을 극복하기 위한 방법 가운데 신호처리기법에 기반하여 여러 장의 저해상도 영상으로부터 고해상도 영상을 복원하는 것과, 다이내믹 레인지가 좁은 여러 장의 영상으로부터 넓은 다이내믹 레인지를 갖는 영상을 복원하는 방법이 있다. 하지만, 일반적으로 실제 영상을 획득하는 과정에서 공간 해상도와 다이내믹 레인지의 제약을 동시에 받게 되므로, 이 두 제약을 동시에 극복하는 연구가 필요하다. 본 논문에서는 영상 장치의 응답 함수의 추정과 함께 공간 해상도와 다이내믹 레이지를 동시에 향상시킬 수 있는 알고리즘을 제안한다. 이를 위해 영상의 공간 해상도 제한과, 다이내믹 레인지의 제약을 포함하는 영상 획득 과정을 모델링하고, 이 영상 획득 모델을 기반으로 하여 영상 입력 장치의 응답 함수를 추정하고, 영상의 공간 해상도와 다이내믹 레인지를 동시에 향상시킬 수 있는 알고리즘을 제안한다. 실험 결과를 통해 제안된 알고리즘이 기존의 고해상도 복읜 알고리즘과 와이드 다이내믹 레인지 영상 복원을 연속적으로 처리한 결과보다 시각적, 수치적으로 더 좋은 결과를 보여줌을 확인할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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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.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.257-262
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• 2021

Objective: Patients with stroke generally diminished ankle range of motion, which decreases balance and walking ability. This study aimed to determine the effect of ankle self-mobilization with movement (s-MWM) on ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index in patients with chronic stroke. Design: Randomized controlled trial design Methods: Twenty-four post-stroke patients participated in this study. The participants were randomized into the control (n = 12) and self-MWM groups (n = 12). Both groups attended standard rehabilitation therapy for 30 minutes per session. In addition, self-MWM group was performed 3 times per week for 8 weeks. All participants have measured ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index in before and after the intervention. Results: After 8 weeks of training, self-MWM group showed greater improvement in ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index than in the control group (p<0.05). Further, self-MWM group had significantly improvement in all dependent variables compared to the pre-test (p<0.05). Conclusions: Our investigation demonstrates that self-MWM is beneficial for improving functional ability. Also, self-MWM was superior to control with respect to improving ankle dorsiflexion passive range of motion, timed up and go test, and dynamic gait index.