• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.260-268
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• 2020

Currently, it is usually a 3D scanner processing method as a laser method. However, the laser method has a disadvantage of slow scanning speed and poor precision. Although optical scanners are used as a method to compensate for these shortcomings, optical scanners are closely related to the distance and precision of the object, and have the disadvantage of being expensive. In this paper, 3D scanner using variable focus lens-based structured light module with improved measurement precision was designed to be high performance, low price, and usable in industrial fields. To this end, designed a telecentric optical system based on a variable focus lens and connected to the telecentric mechanism of the step motor and lens to adjust the focus of the variable lens. Designed a connection structure with optimized scalability of hardware circuits that configures a stepper motor to form a system with a built-in processor. In addition, by applying an algorithm that can simultaneously acquire high-resolution texture image and depth information and apply image synthesis technology and GPU-based high-speed structured light processing technology, it is also stable for changes to external light. We will designed and implemented for further improving high measurement precision.

• 제어로봇시스템학회논문지
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• 제16권11호
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• pp.1082-1088
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• 2010

In this paper, we propose a new gel-type biomimetic variable-focus lens system. The miniaturization of conventional lens system is limited due to the use of a set of glass lenses for adjusting the focal length. Biologically inspired by the focus adjustment mechanism of the human eye, a gel-type single lens system with variable-focus is presented. The proposed system consists of a gel-type lens, mechanical parts such as body, rotation ring, and winding-type SMA actuator. In addition, the proposed system is designed to operate with a simple and miniaturized mechanical structure using a new attachment and driving mechanism. The focusing performance of the proposed system is verified through a series of experiments and measurements of the shape of the lens using tomography.

• Journal of the Optical Society of Korea
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• 제16권1호
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• pp.22-28
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• 2012

We report a focal-length tunable liquid lens based on thermopneumatically driven fluidic pressure. The fluidic pressure is generated by deformation of an elastomeric diaphragm induced by thermopneumaticity from a laterally integrated microheater sealed within an air chamber. The pressure is transmitted by a confined liquid to a lens diaphragm through an internal fluid channel. The liquid filling under the lens diaphragm functions as a liquid lens for dynamic focusing with properties depending on the curvature of the deformed diaphragm. The diaphragm area of the air chamber is designed five times larger than that of the lens cavity to yield high focal-length tunability by amplified deflection of the lens diaphragm. With our method, we achieved excellent focal-length tunability from infinity (without an input current) to 4 mm (with an input current of 12 mA) with a lens aperture diameter of 2 mm.

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.85-86
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• 2006

• 한국기계가공학회지
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• 제19권6호
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.286-293
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• 2009

In this paper, we present an optimal shape design method for a dielectric microlens which is used to focus an incoming infrared plane wave in wideband, by exploiting the finite difference time domain (FDTD) technique and the topology optimization technique. Topology optimization is a scheme to search an optimal shape by adjusting the material properties, which are design variables, within the design space. And by introducing the adjoint variable method, we can effectively calculate a derivative of the objective function with respect to the design variable. To verify the proposed method, a shape design problem of a dielectric microlens is tested when illuminated by a transverse electric (TE)-polarized infrared plane wave. In this problem, the design variable is the dielectric constant within the design space of a dielectric microlens. The design objective is to maximally focus the incoming magnetic field at a specific point in wideband.

• Current Optics and Photonics
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• 제3권2호
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• pp.177-180
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• 2019

Based on liquid-lens technology and our previous findings on the optical model of the Chinese eye, the liquid lens is applied in the research of the crystalline-lens optical model. Theoretical models of three-layer liquid lenses are built with COMSOL software, and the effect of voltage on the shape of the interface between two liquids is analyzed. By polynomial fitting, different equations describing the interface shape are set up under different voltages. Finally, the optical system of the human eye with a three-layer liquid lens is built and analyzed with Zemax optical design software, and moreover the optical system models of emmetropia, myopia, and hyperopia are presented. This method to build a model of the human eye with a variable-focus liquid lens can provide a novel idea for more practical human-eye models for clinical regulation and control in the future.

• Journal of information and communication convergence engineering
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• 제7권4호
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• pp.507-515
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• 2009

In this paper, we propose an image signal processor (ISP) for an ultra small HD-grade video sensor with 3A (AWB, AE, and AF) in camera phones that can process 720P/30fps videos. In order to enhance the video quality of the systems, it is necessary to achieve the high performance of the 3A. The proposed AWB algorithm multiplies the adjusted coefficients of color gains to the captured data of white objects. The proposed AE method adopts the index step moving based on the difference between an averaged Y luminance and a target luminance, together with IIR filters with variable time responses. The proposed AF technique controls the focus curve to find the lens position that maximizes the integrated high frequency components in luminance values by using highpass filters. Finally, we compare the image quality captured from our system to the quality of a commercial HD camcorder in order to evaluate the performance of the proposed ISP. The proposed ISP system is also fabricated with 0.18um CMOS flash memory process.