• Title, Summary, Keyword: Control algorithm for light level

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A Design of an LED Sensor Luminaire for Visual Function Improvement (시각적 기능개선을 위한 LED 센서 등기구 설계)

  • Seo, Jung-Nam;Yu, Yong-Su;Yeo, In-Seon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.134-137
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    • 2010
  • An LED sensor luminaire for visual function improvement necessitates the control algorithm for light level adjustment and the appropriate lens design. The control algorithm adapts to surround lighting condition, and thus has the advantages of energy saving and glare reduction. The multi-cell lens design improves color temperature uniformity and spatial light distribution of the luminaire. Experimental and simulated results show that this approach contributes noticeably to energy saving and color temperature uniformity of the LED sensor luminaire.

Dimming Level Control Technique for Lighting / Communication Functions in Visible Light Communication Systems (가시광통신 시스템에서 조명/통신 기능을 위한 효과적인 Dimming level control 기법)

  • Lee, Kyu-Jin
    • Journal of Convergence for Information Technology
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    • v.8 no.5
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    • pp.153-158
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    • 2018
  • In this paper, we have studied a dimming level control method to satisfy both lighting and communication performance in visible light communication system. In the case of the most commonly used OOK and RZ-OOK modulation schemes, continuous Burst Zero Duration will seriously degrade the lighting function. This causes not only the illumination but also the performance of the entire system to deteriorate. Through this study, we analyzed the dimming level characteristics of the existing system and proposed the Illegal Pulse Insertion (IPI) algorithm as a technique to increase the dimming level. Through this, it is possible to effectively control the dimming level and improve the QoS of both lighting and communication by resolving the flicker phenomenon and dimming level reduction in the existing modulation and demodulation system.

Adaptive Denoising for Low Light Level Environment Using Frequency Domain Analysis (주파수 해석에 따른 저조도 환경의 적응적 잡음제거)

  • Yi, Jeong-Youn;Lee, Seong-Won
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.9
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    • pp.128-137
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    • 2012
  • When a CCD camera acquires images in the low light level environment, not only the image signals but also noise components are amplified by the AGC (auto gain control) circuit. Since the noise level in the images acquired in the dark is very high, it is difficult to remove noise with existing denoising algorithms that are targeting the images taken in the normal light condition. In this paper, we proposed an adaptive denoising algorithm that can efficiently remove significant noises caused by the low light level. First, the window including a target pixel is transformed to the frequency domain. Then the algorithm compares the characteristics of equally divided four frequency bands. Finally the noises are adaptively removed according to the frequency characteristics. The proposed algorithm successfully improves the quality of low light level images than the existing algorithms do.

New Lighting Control System for Light Devices (새로운 조명기기 점등제어 시스템)

  • In, Chi-Goog;Yoon, Dal-Hwan;Lin, Chi-Ho
    • Journal of IKEEE
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    • v.15 no.4
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    • pp.261-266
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    • 2011
  • In this paper, new efficient lighting control system for light devices is proposed to reduce power consumption and increases LED life-cycle and heat efficiency of LED lighting module. The new proposed lighting control system for light devices divides into 4 stages according to the illuminance surrounding by measuring illuminance and apply to automatic pattern lighting algorithm. And via level check will be light up for set time by applying intersection lighting algorithm of magic square pattern forming a fully symmetrical. Experimental analysis results, shows heating value and power consumption reduced to maximum 30 percent and lifetime of LED improved to maximum 60 percent in comparison with previous lighting system so applying system to LED streetlight, stable and high energy efficiency can be acquired.

Intelligent Lighting Control using Wireless Sensor Networks for Media Production

  • Park, Hee-Min;Burke, Jeff;Srivastava, Mani B.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.3 no.5
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    • pp.423-443
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    • 2009
  • We present the design and implementation of a unique sensing and actuation application -- the Illuminator: a sensor network-based intelligent light control system for entertainment and media production. Unlike most sensor network applications, which focus on sensing alone, a distinctive aspect of the Illuminator is that it closes the loop from light sensing to lighting control. We describe the Illuminator's design requirements, system architecture, algorithms, implementation and experimental results. The system uses the Illumimote, a multi-modal and high fidelity light sensor module well-suited for wireless sensor networks, to satisfy the high-performance light sensing requirements of entertainment and media production applications. The Illuminator system is a toolset to characterize the illumination profile of a deployed set of fixed position lights, generate desired lighting effects for moving targets (actors, scenic elements, etc.) based on user constraints expressed in a formal language, and to assist in the set up of lights to achieve the same illumination profile in multiple venues. After characterizing deployed lights, the Illuminator computes optimal light settings at run-time to achieve a user-specified actuation profile, using an optimization framework based on a genetic algorithm. Uniquely, it can use deployed sensors to incorporate changing ambient lighting conditions and moving targets into actuation. Experimental results demonstrate that the Illuminator handles various high-level user requirements and generates an optimal light actuation profile. These results suggest that the Illuminator system supports entertainment and media production applications.

Smart Dimming Control Algorithm for Reducing Power Consumption of LED TV Backlight (LED TV 백라이트 소비전력 저감을 위한 스마트 디밍 알고리즘 개발)

  • Ryu, Je-Seung;Park, Ju-Hee;Lim, Seong-Ho;Kim, Tae-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.4
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    • pp.320-326
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    • 2014
  • In this paper, the new smart dimming algorithm which is mixed with PWM and PAM control method is proposed for reducing the power consumption of LED TV Backlight. The proposed technique is using the curve characteristics of LED forward voltage and current which is proportionally changing LED forward voltage as changing LED forward current. Therefore, each PWM and PAM control method has different LED forward voltage and current in the same brightness condition. The PWM control method adjusts the brightness of LED TV Backlight by only varying the duty ratio of PWM and constantly sustaining the amplitude of LED forward current and voltage. So, the level of LED forward current and voltage in the PWM control method is relatively high and constant regardless of duty ratio of PWM. On the other hand, the PAM control method adjusts the brightness of LED TV Backlight by directly varying the level of LED forward current. So, the level of LED forward current and voltage in the PAM control method is lowered according to the brightness level. For the above-mentioned reason, the PAM control method has the advantage of reducing the total power consumption of LED TV Backlight at the brightness condition of below 100%, compared with PWM control method. By implementing this characteristic to LED driver circuit with control algorithm in MCU, the power consumption of LED TV Backlight can expect to be reduced. The effectiveness of the proposed method, new smart dimming algorithm, CPWAM(=Conditional Pulse Width Amplitude Modulation), has been verified by experimental results.

Incremental Displacement Estimation Algorithm for Real-Time Structural Displacement Monitoring (실시간 구조물 변위 모니터링을 위한 증분형 변위 측정 알고리즘)

  • Jeon, Hae-Min;Shin, Jae-Uk;Myeong, Wan-Cheol;Myung, Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.6
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    • pp.579-583
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    • 2012
  • The purpose of this paper is to suggest IDE (Incremental Displacement Estimation) algorithm for the previously proposed visually servoed paired structured light system. The system is composed of two sides facing with each other, each with one or two lasers with a 2-DOF manipulator, a camera, and a screen. The 6-DOF displacement between two sides can be estimated by calculating the positions of the projected laser beams and rotation angles of the manipulators. In the previous study, Newton-Raphson or EKF (Extended Kalman Filter) has been used as an estimation algorithm. Although the various experimental tests have validated the performance of the system and estimation algorithms, the computation time is relatively long since aforementioned algorithms are iterative methods. Therefore, in this paper, a non-iterative incremental displacement estimation algorithm which updates the previously estimated displacement with a difference of the previous and the current observed data is introduced. To verify the performance of the algorithm, experimental tests have been performed. The results show that the proposed non-iterative algorithm estimates the displacement with the same level of accuracy compared to the EKF with multiple iterations with significantly less computation time.

Analysis on Dimming Control Effect by Algorithm Variation for Direct/Indirect Lighting in a Small Office (알고리듬 변화에 따른 직/간접 조명시스템에 대한 디밍제어 효과분석)

  • Kim, Soo-Young
    • Journal of the Korean Solar Energy Society
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    • v.28 no.5
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    • pp.36-48
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    • 2008
  • This study examines the influence of control algorithms on dimming performance to determine appropriate control setting when direct/indirect lighting is controlled by a daylight dimming system. Computer simulation were performed for a small office with double skin envelope under various daylight conditions. A retractable fabric shading and Venetian blind were applied for internal and external envelopes under three CIE standard sky conditions. Unshielded and partially-shielded photosensors were used, and three control algorithms were applied for the sensors. In general, dimming level was too excessive due to the direct impact of light from lighting fixture to the photosensor. Providing insufficient lighting output, the unshielded photosensor completely failed to secure required illuminance under any daylight condition. When a partially-shielded photosensor was applied under clear sky, three setting points functioned effectively. Less sensitivity for the partially-shielded photosensor was effective to control the dimming system optimally with reasonable energy saving. However, the daylight dimming control system for direct/indirect lighting does not appear to be energy effective when photosensors without enough shielded area is installed on ceiling where light from fixtures reaches directly.

Local Dimming Technique for High Dynamic Range LCD by White LED Backlight with New Control Algorithm

  • Huang, K.T.;Lee, Boris;Tsai, C.W.;Wu, C.C.;Cheng, C.F.;Chao, Andy;Yu, C.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.143-146
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    • 2008
  • Dynamic range of LCD panel can be dramatically improved by adaptive dimming technique. Adaptive control of LED backlight by input signal can reduce the light leakage of LCD panel and achieve high contrast ratio. An algorithm is proposed to distinguish the input signal and get proper luminance level. For lower cost of LCD panel, white light LED is used to accomplish 2D dimming and get better image performance of LCD.

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Noise Estimation based on Standard Deviation and Sigmoid Function Using a Posteriori Signal to Noise Ratio in Nonstationary Noisy Environments

  • Lee, Soo-Jeong;Kim, Soon-Hyob
    • International Journal of Control, Automation, and Systems
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    • v.6 no.6
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    • pp.818-827
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    • 2008
  • In this paper, we propose a new noise estimation and reduction algorithm for stationary and nonstationary noisy environments. This approach uses an algorithm that classifies the speech and noise signal contributions in time-frequency bins. It relies on the ratio of the normalized standard deviation of the noisy power spectrum in time-frequency bins to its average. If the ratio is greater than an adaptive estimator, speech is considered to be present. The propose method uses an auto control parameter for an adaptive estimator to work well in highly nonstationary noisy environments. The auto control parameter is controlled by a linear function using a posteriori signal to noise ratio(SNR) according to the increase or the decrease of the noise level. The estimated clean speech power spectrum is obtained by a modified gain function and the updated noisy power spectrum of the time-frequency bin. This new algorithm has the advantages of much more simplicity and light computational load for estimating the stationary and nonstationary noise environments. The proposed algorithm is superior to conventional methods. To evaluate the algorithm's performance, we test it using the NOIZEUS database, and use the segment signal-to-noise ratio(SNR) and ITU-T P.835 as evaluation criteria.