• Title/Summary/Keyword: contrast controller

검색결과 49건 처리시간 0.027초

Design of an Image Processor for UXGA Class LCD

  • Cho, Hwa-Hyun;Choi, Myung-Ryul
    • Journal of Information Display
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    • 제2권2호
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    • pp.13-21
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    • 2001
  • We propose a universal image processor for a-Si TFT LCD of UXGA class that can display the full screen on the LCD panel with low resolution of video sources such as NTSC, VGA, SVGA, XGA, and SXGA by using the proposed interpolation filter. In addition, we propose a real-time contrast controller for image improvement of multi-gray scale image. The operation of the proposed methods has been verified using Synopsys VHDL and computer simulation. Results show that the proposed methods might be suitable for a UXGA LCD controller for real-time image improvement.

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The Design and Implementation of the Adaptive Contrast Controller System (적응형 콘트라스트 제어 시스템의 설계 및 구현)

  • 김철순;권병헌;곽경섭
    • Journal of Korea Multimedia Society
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    • 제5권1호
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    • pp.38-46
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    • 2002
  • In this paper, we present an adaptive contrast controller for improving the Quality of motion-picture in the video signals on the display. Using a median of image signals, we can improve the contrast according to the middle brightness, adaptively. In addition, the proposed method is useful for real-time image processing and can be composed of simpler hardware structure than other conventional methods because it does not require field and frame memory for computed data. The proposed method can be applied for video signals as well as the still image, while existing methods are confined to only the static image Also, we designed the algorithm through the VHDL, and implemented it through the FPGA. From the testing results, we see that the proposed method can effectively improve the image contrast.

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A Study on Dose Reduction Method according to Slice Thickness Change using Automatic Exposure Controller and Manual Exposure in Intervention (인터벤션에서 자동노출제어장치와 수동노출 사용 시 두께 변화에 따른 선량감소 방안 연구)

  • Hwang, Jun-Ho;Jung, Ku-Min;Choi, Ji-An;Kim, Hyun-Soo;Lee, Kyung-Bae
    • Journal of radiological science and technology
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    • 제41권2호
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    • pp.115-122
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    • 2018
  • We aims to perform comparative analysis on the dose area and image qualities varying on the slice thickness when using Automatic Exposure Controller (AEC) and manual exposure; thus, it wants to suggest a measure to reduce exposure dose by setting the optimal examination condition for each slice thickness. The method was to set the thickness as Thin, Normal, and Heavy adult and evaluate the dose area, spatial resolution, low contrast resolution, Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) according to each slice thickness by using the AEC and the manual exposure controller. The dose area according to each slice thickness all increased both when using the AEC and the manual exposure. However, the manual exposure showed lower dose area product than the AEC. Spatial resolutions and low contrast resolutions were all observed to be higher than the evaluation standard. Also, the SNR and CNR of each thickness all increased when using the AEC. When using the manual exposure, SNR and CNR increased in all cases other than the Heavy Adult. Consequently, the Thin and Normal Adult showed dose reduction about 2 times when using the manual exposure controller, while ensuring the image quality. Heavy adult was able to maintain good image quality by using AEC.

DC MOTOR SPEED CONTROL USING PID CONTROLLER

  • Loucif, Fatiha
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.2557-2561
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    • 2005
  • The PID controller design and choosing PID parameters according to system response are proposed in this paper. Here PID controller is employed to control DC motor speed and Matlab program is used for calculation and simulation. Choosing PID parameters are demonstrated by several contrast experiments and a way for setting PID parameters values is discussed.

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The improved contrast control method for LCD monitor

  • Kwon, Byong-Heon;Park, Myung-Ryul;Youn, Jin-Suk
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2002년도 ITC-CSCC -3
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    • pp.1811-1814
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    • 2002
  • In this paper, we propose an improved contrast control method f9r image improvement of multi-gray scale image. The proposed contrast control method can improve contrast of image by changing gradient of weight as the type of input image. In addition, the proposed method does not require field and frame memory for large amount of computed data. And, the proposed method can be easily applied to the FPD fur real-time processing because of its less hardware complexity than that of the conventional methods. Also it can flexibly control the contrast of input gray level by varying the weight values that control the contrast range. The operation and performance of the proposed controller have been verified using computer simulation.

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Regional Contrast Enhancement for Local Dimming Backlight on Small-sized Mobile Display

  • Chung, Jin-Young;Kim, Ki-Doo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.972-974
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    • 2009
  • This paper presents smart regional contrast enhancement technique of partitioned image for local dimming backlight on small-sized mobile display to reach two goals. One is to save the power consumption, and the other to improve contrast ratio of display image. Recently new advanced method is proposed, named local dimming method, that backlight LED is positioned on backside of the display panel. So it is important to partition an image by sub blocks and then post-processing independantly. This means regional contrast enhancement. After partitioning, we compare the mean luminance(Y) value of each sub-block image with the one of original whole image. If some blocks have the mean value lower than the one of whole image, they are processed with the proposed method and others are bypassed. Simultaneously the information of the processed blocks are transferred to BLC(Backlight LED Controller). And then the supply current of each backlight LED is reduced to realize the contrast ratio enhancement and at the same time to power consumption reduction. In addition, we verify this proposed method is free from blocking artifacts.

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Design of an Adaptive Contrast Controller with compensation of Picture brightness (화면 밝기 보상기능을 고려한 Contrast Controller 설계)

  • Kim, Hee-Chul;Kwon, Byong-Heon;Choi, Myung-Ryul
    • Proceedings of the Korea Information Processing Society Conference
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    • 한국정보처리학회 2001년도 춘계학술발표논문집 (하)
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    • pp.867-870
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    • 2001
  • 본 논문에서는 디스플레이상에서 영상 향상을 위한 다계조 콘트라스트 조절장치를 제안하였다. 제안한 방식은 추가적인 메모리를 필요하지 않고, 입력 계조 레벨에 상관없이 영상향상이 가능하다. 또한 입력 영상의 자기 정보를 고려하여 원화상의 밝기정보를 최대한 보상할 수 있으며 기존의 방식에 비해 하드웨어 구성이 간단하여 실시간 처리를 요하는 분야에 쉽게 적용 가능하고 입력되는 콘트라스 영역의 가중치 값을 사용자가 임의적으로 변화시킴으로써 콘트라스트 조정이 가능하다. 제안한 콘트라스트 조정장치는 컴퓨터 시뮬레이션을 통하여 검증하였으며, 시뮬레이션 결과 영상 향상을 확인하였다.

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A new training method for neuro-control of a manipulator (매니퓰레이터의 신경제어를 위한 새로운 학습 방법)

  • 경계현;고명삼;이범희
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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    • pp.1022-1027
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    • 1991
  • A new method to control a robot manipulator by neural networks is proposed. The controller is composed of both a PD controller and a neural network-based feedforward controller. MLP(multi-layer perceptron) neural network is used for the feedforward controller and trained by BP(back-propagation) learning rule. Error terms for BP learning rule are composed of the outputs of a PD controller and the acceleration errors of manipulator joints. We compare the proposed method with existing ones and contrast performances of them by simulation. Also, We discuss the real application of the proposed method in consideration of the learning time of the neural network and the time required for sensing the joint acceleration.

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Comparison Analysis of Resonant Controllers for Current Regulation of Selective Active Power Filter with Mixed Current Reference

  • Yi, Hao;Zhuo, Fang;Li, Yu;Zhang, Yanjun;Zhan, Wenda
    • Journal of Power Electronics
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    • 제13권5호
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    • pp.861-876
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    • 2013
  • Instead of extracting every selected harmonic component, the current reference of selective active power filter (APF) can be also obtained by filtering out the fundamental component from distorted load current for computation efficiency. This type of mixed current reference contains kinds of harmonic components and easily involves noises. In this condition, selective harmonic compensation must be realized by the current controller. With regard that selectivity is the most significant feature of controller, this paper presents specific comparison analysis between two types of resonant controllers: proportional-resonant (PR) controller and vector-resonant (VR) controller. The comparison analysis covers the relations, performances, and stability of both controllers. Analysis results conclude that the poorer selectivity of the PR controller could be relatively improved, but limitations from system stability make the improvement hardly realized. By contrast, the VR controller exhibits excellent selectivity and is more suitable for selective APF with mixed current reference. Experimental results from laboratory prototype validate the reasonability of analysis. And the features of each resonant controller are concluded.

Design Method of a Parallel Feedforward Compensator for Passivation of Linear Systems (선형 시스템 수동화를 위한 병렬 앞먹임 보상기 설계방법 연구)

  • 손영익
    • Journal of Institute of Control, Robotics and Systems
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    • 제10권7호
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    • pp.590-596
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    • 2004
  • A passivity-based dynamic output feedback controller design is considered for a finite collection of non-square linear systems. Design of a single controller for a set of plants i.e. simultaneous stabilization is an important issue in the area of robust control design. We first determine a squaring gain matrix and an additional dynamics that is connected to the systems in a feedforward way, then a static passivating control law is designed. Consequently, the actual feedback controller will be the static control law combined with the feedforward dynamics. A necessary and sufficient condition for the existence of the parallel feedforward compensator is given by the static output feedback formulation. In contrast to the previous result [1], a technical condition for constructing the parallel feedforward compensator is removed by proposing a new type of the parallel compensator.