• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.909-916
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• 2009

This paper presents the automatic vision algorithm to generate and calibrate reference phase plane to improve the accuracy of 3D measuring machine of using phase shifting projection moire method, which is not traditional N-bucket method, but is based on direct image processing method to the pattern projection image. Generally, to acquire accurate reference phase plane, the calibration specimen with well treated surface is needed, and detailed calibration method should be performed. For the cost reduction of specimen manufacturing and the calibration time reduction, on the specimen, not specially designed, with general accuracy level, an efficient calibration procedure for the reference phase generation is proposed. The proposed vision algorithm is developed to extract the line center points of the projected line pattern from acquired images, derive the line feature information consisting of its slope and intercept by using sampled feature points, and finally generate the related reference phase between line pairs. Experimental results show that the proposed method make reference phase plane with a good accuracy under noisy environment and the proposed algorithm can reduce the total cost to make high accurate calibration specimen, also increase the accuracy of reference phase plane, and reduce the complex calibration procedure to move grid via N-bucket algorithm precisely.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4704-4710
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• 2015

The purpose of this study is to obtain a useful diagnostic image by increasing the signal strength of the peripheral artery, was to use a T1 shortening effect of gadolinium contrast agents to improve the disadvantages of the phase image. From october to december 2014 thirty patients were underwent the MRI scanning, except for heart disease. Research method was evaluated comparing the image after gadolinium contrast MR image acquisition step before evaluating the difference between the signal intensity for T1 shortening effect. In frontal lobe 19.45%, temporal lobe 23.09%, occipital lobe 25.45%, parietal lobe 18.82%, cerebellum 20.93% after peripheral arterial signal strength results of gadolinium contrast agent injection was increased significantly after injection of gadolinium both statistically significant. After injecting a contrast agent gadolinium in SWI by increasing the signal strength of the T1 shortening effect can be obtained when using the phase image to give a useful image in diagnosis and treatment.

• 한국가시화정보학회:학술대회논문집
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• 2001.12a
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• pp.1-5
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• 2001

A particle image velocimetry (PIV) was applied to a flow measurement in a transonic centrifugal impeller. A phase locked measurement technique every $20\%$ blade pitch enabled a reconstruction of a velocity field over one blade pitch. The measured velocity field at the inducer of impeller clearly showed a shock wave generated on the suction surface of a blade.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.3
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• pp.225-236
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• 2009

Image inpainting is the process of reconstructing lost or deteriorated parts of images using information from surrounding areas. We propose a computationally efficient and fast phase-field method which uses automatic switching parameter, adaptive time step, and automatic stopping of calculation. The algorithm is based on an energy functional. We demonstrate the performance of our new method and compare it with a previous method.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.867-870
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• 2007

In order to solve image sticking phenomena, the gas-phase and liquid-phase interfacial reactions of photosensitive polyimide can annihilate photoreactive carbon-carbon double bonds, which remain after photo-alignment process. The annihilation processes dramatically affect residual DC and photochemical reorientation of photoactive functional groups.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.455-456
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• 2008

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.349-354
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• 1999

Electro-Optical Camera (EOC) is the main payload of the KOMPSAT-1 satellite to perform the mission of cartography that builds up a digital map of Korean territory including a digital terrain elevation map. This paper discusses the issues of the digital image simulation of EOC for the generation of EOC simulated scene as taken by EOC at 685km altitude on orbit. For the purpose, simulation work has been performed with the sensor models of EOC and the satellite platform motions models through image chain analysis from the illumination source (Sun) to a simulated image output in digital number. MODTRAN fur radiance calculation, MTF models of optics, detector and motions of EOC for system point spread function (PSF), and signal chain equations for digital number output are described. Several noise models of EOC are also considered. The final output is the EOC simulated image in digital number. The simulation technique can be used in several phase of a spaceborne electro-optical system development project, feasibility study phase, design, manufacturing, test phases, ground image processing phases, and so on.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.43-51
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• 2004

In this paper, we propose a high-level optical encryption system, which is tolerant with noises and cropping, by encrypting the phase-encoded CGH pattern of original image with the phase-encoded Fresnel diffraction pattern of random key images. For encryption, the phase-encoded CGH pattern of original image is multiplied by conjugate components which are the phase-encoded Fresnel diffraction patterns of random key images. The original information can be reconstructed by multiplying encrypted image by phase-encoded Fresnel diffraction pattern of random key images and performing Fourier transform of the multiplication result. The proposed system is robust to noises and cropping due to characteristics of CGH pattern and can guarantee high-level encryption by using Fresnel diffraction information. We verified the validity of proposed system by computer simulations, numerical analysis of noises and cropping effect and optical experiment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.10-21
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• 2008

The present paper propose a real-time moving object recognition and tracking method using the wavelet-based neural network and invariant moments. Candidate moving region detection phase which is the first step of the proposed method detects the candidate regions where a pixel value changes occur due to object movement based on the difference image analysis between continued two image frames. The object recognition phase which is second step of proposed method recognizes the vehicle regions from the detected candidate regions using wavelet neurual-network. From object tracking Phase which is third step the recognized vehicle regions tracks using matching methods of wavelet invariant moments bases to recognized object. To detect a moving object from image sequence the candidate regions detection phase uses an adaptive thresholding method between previous image and current image as result it was robust surroundings environmental change and moving object detections were possible. And by using wavelet features to recognize and tracking of vehicle, the proposed method decrease calculation time and not only it will be able to minimize the effect in compliance with noise of road image, vehicle recognition accuracy became improved. The result which it experiments from the image which it acquires from the general road image sequence and vehicle detection rate is 92.8%, the computing time per frame is 0.24 seconds. The proposed method can be efficiently apply to a real-time intelligence road traffic surveillance system.

• Korean Journal of Optics and Photonics
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• v.23 no.4
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• pp.135-142
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• 2012

We have developed a measurement method of the refractive index profile of an optical fiber by using diffraction phase microscopy. In the microscope system, the reference light was extracted directly from the probe light that passed through the sample by means of pinhole filtering with a diffraction grating. The spatial interference pattern produced by the probe light and the reference light was processed to generate the phase image of the sample fiber. The index profile was obtained by the inverse Abel transform of the phase profile. In order to remove the background phase that originated from the index difference between the cladding and the surrounding medium, the background phase was calculated from the phase data of the cladding to make a core phase profile that can be directly transformed to the index profile of the core without the full phase image that includes the entire cladding part.