• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.3 s.357
• /
• pp.12-19
• /
• 2007

This paper proposes the enhanced auto-focus algorithm detecting several objects and selecting the target object. Proposed algorithm first detects some objects distributed in the image using focus measure operator and multi-window and then selects the target object through fuzzy reasoning with three fuzzy membership functions. Implementation can be simple because it only needs image sensor instead of infrared or ultrasonic equipment. Experimental result shows that the proposed algorithm can improve the quality of image by focusing to the target object.

• Journal of Digital Convergence
• /
• v.10 no.11
• /
• pp.331-335
• /
• 2012

Many researches have been performed the analysis and experiments on auto-focus lens due to the development of camera module which is used in mobile-phone recently. Various types of voice coil motor are used mostly in the view point of actuators. Various type of magnetic flux flow is made by the combination of magnet, coil and yoke, etc. And the function of auto-focus is made by the proper combination of the lens components. In this research, some of the simple and economic structure is chosen to investigate the characteristics analytically among various types of lens which are used in industries. Desired level of lens module design was achieved by electromagnetic analysis using ANSYS$^{TM}$ finite element analysis program.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.10a
• /
• pp.107-107
• /
• 2003

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.6
• /
• pp.1493-1498
• /
• 2015

The autofocus system is automatically to drive the focus. It is very important to computer vision system. In the case of a compact camera, the actuator technology is used for auto-focus in mass production. the position sensor is required, the circuit configuration and easy method is widely used in VCM, compared to the stability of the drive size and the noise is a big stepping motor type, size has a piezo system having a humidity problem and the small leaded vulnerability. In addition, there is a liquid lens system, the advantages of low power in a compact structure but also a structure with proven quality and reliability and features required pressure. In this paper, we implement two control systems that can control the actuator as a liquid range of VCM using a sharpness of the image acquired by the image sensor automatically initiates 5Mpixel class was the implementation verification of focusing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.1003-1006
• /
• 2005

Demand of Auto Focus for Camera module is increased very fast in these days and will be adapted to most of mobile phones in next few years instead of traditional method, fixed focus. To make auto focus function, 2 kinds of solutions, VCM(Voice Coil Motor) and Piezo linear motor are normally used. In this paper, VCM which commercially strong candidate for Auto focus mechanism was investigated to verify principles are match up to the actual operation. Auto focus algorithm is different between 1 chip and 2 chip solution. Normally 2 chip is more complicate than the other. To have best performance on this function, hysteresis and depth of field(DOF) table should be optimized.

• Korean Journal of Optics and Photonics
• /
• v.31 no.6
• /
• pp.314-320
• /
• 2020

The optics used in an infrared imaging system has a strong refractive-index change according to temperature, so an autofocus control function is essential for a military infrared imaging system with a wide operating-temperature range. In this study, we design a triple-magnification infrared imaging system, and to compensate for the change in refractive index according to temperature we measure the change in the lens focus according to temperature. The autofocus control function was implemented by using the measured movement amount, and we could obtain an image with satisfactory resolution performance over a wide range of operating temperatures.

• Journal of the Korea Computer Industry Society
• /
• v.9 no.2
• /
• pp.69-76
• /
• 2008

This paper implement an Camcorder NTSC camera autofocus control system on the DSP Board. The information of camera lens control obtain the only brightness simple image processing from the NTSC camcoder camera image. The exact focus makes the exact boundaries. The camera lens control that the increase sum of the useful ingredient values. Useful value obtained experiment value. Also noise is except because a big value of the ingredients so that obtained focus more accurate value.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.12 s.115
• /
• pp.1249-1258
• /
• 2006

Two-dimensional(2-D) radar images, namely, ISAR images from a maneuvering target include unwanted phase errors due to the target's motion. These phase errors make ISAR images to be blurred. The ISAR autofocus technique is required in order to remove these unwanted phase errors. Unless those unwanted phase errors produced by the target's motion are removed prior to target identification, we cannot expect a reliable target identification performance. In this paper, we use the entropy-based ISAR autofocus technique which consists of two steps: range alignment and phase adjustment. We analyze a relationship between the number of sampling point and a image quality in a range alignment algorithm and also analyze a technique for reducing computation time of the SSA(Stage-by-Stage Approachng) algorithm in a phase adjustment.

• Korean Journal of Optics and Photonics
• /
• v.7 no.2
• /
• pp.101-111
• /
• 1996

Optical microscopes integrated with CCD cameras are widely used for automatic inspection of precision circuit patterns fabricated on glass masks and silicon wafers. For this application it is important to position the object always is focus so that the image appears in good quality while the microscope scans the object. However, as the magnification of the microscope is taken large for fine resolution the depth of focus becomes small, often in submicron ranges, requiring special care in focusing. This study proposes a new auto-focusing method, which can be readily incorporated in existing optical configuration of microscope. This method is based on optical triangulation using a separate beam of laser and two photodiodes, eliminating focus errors caused by surface roughness and waviness. Experimental results prove that the method can produce focus error signals which are very sensitive with a resolution of 5 nm within 0.5 ${\mu}{\textrm}{m}$ accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.499-500
• /
• 2014

화재발생 시 인명 안전을 위하여 초기의 화재감지가 매우 중요한 요인이다. 특히 도로터널, 지하철역사 등 광범위 폐쇄공간에서 연기에 의한 질식사 등 2차 피해의 발생위험이 높다. 이에 최근 광범위 공간에서 적외선 레이저를 활용한 원거리 연기검출 화재탐지기에 대한 연구가 진행되고 있다. 이러한 레이저 기반 원거리 연기검출장치는 이격(100m 이상) 설치되는 레이저 발신기와 수신기의 레이저 포인트가 정확히 정합되어야 한다. 아울러, 레이저 발신기와 수신기 사이의 거리에 비례하여 레이저 초점의 이동거리가 매우 민감하게 변화하므로 이를 정확히 정합하기 위한 고정밀 제어장치가 필요하다. 따라서 본 논문에서는 복수개의 레이저 발신모듈과 복수개의 조도센서(CdS)를 통해 초점의 정합을 자동 추적할 수 있는 알고리즘을 설계, 구현하였다. 이는 초기 레이저 초점의 설정과 이후 외부환경에 따른 초점의 틀어짐을 자동 보정하여 다양한 레이저 인식 장치에 적용될 것으로 사료된다.