• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.115-120
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• 2012

In this paper, we present a method to automatically quantify the three-dimensional (3D) volume of red blood cells (RBCs) using off-axis digital holographic microscopy. The RBCs digital holograms are recorded via a CCD camera using an off-axis interferometry setup. The RBCs' phase image is reconstructed from the recorded off-axis digital hologram by a computational reconstruction algorithm. The watershed segmentation algorithm is applied to the reconstructed phase image to remove background parts and obtain clear targets in the phase image with many single RBCs. After segmenting the reconstructed RBCs' phase image, all single RBCs are extracted, and the 3D volume of each single RBC is then measured with the surface area and the phase values of the corresponding RBC. In order to demonstrate the feasibility of the proposed method to automatically calculate the 3D volume of RBC, two typical shapes of RBCs, i.e., stomatocyte/discocyte, are tested via experiments. Statistical distributions of 3D volume for each class of RBC are generated by using our algorithm. Statistical hypothesis testing is conducted to investigate the difference between the statistical distributions for the two typical shapes of RBCs. Our experimental results illustrate that our study opens the possibility of automated quantitative analysis of 3D volume in various types of RBCs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.350-353
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• 2013

In this paper, a hardware implementation of phase calculator for extracting 3D depth image from TOF(Time-Of-Flight) sensor is proposed. The designed phase calculator, which adopts redundant binary number systems and a pipelined architecture to improve throughput and speed, performs arctangent operation using vectoring mode of DCORDIC algorithm. Fixed-point MATLAB simulations are carried out to determine the optimized bit-widths and number of iteration. The designed phase calculator is verified by emulating the restoration of virtual 3D data using MATLAB/Simulink and FPGA-in-the-loop verification, and the estimated performance is about 7.5 Gbps at 469 MHz clock frequency.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.365-368
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• 2000

This paper describes image-rejection down conversion mixer for bluetooth application using 0.35u CMOS process. the proposed architecture is composed of LO phase shifter, mixer core, IF buffer, and IF phase shifter. IF phase shifter is designed using polyphase fillet. Simulation results show conversion gain = l0㏈, input 1㏈ compression point = -15.7㏈m. input third-order intercept point(IIP3) = -4.4㏈m, and image-rejection ratio = 37.8㏈, respectively, at 3V supply voltage, and 15.7㎃ current.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.87-90
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• 2002

A digital watermark is an invisible mark embedded in a digital image which used for copyright protection. In this paper, we propose a new optical watermarking system. A optical watermarking system is applied for digital watermarking by phase hologram and Mach-Zehnder interferometer. A optical watermarking technique to be hidden is phase modulated in a random patten, and its Fourier-transformed hologram image is superposed on a content image. The autentication information extract by using Mach-zehnder interferometer.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.227-230
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• 2002

A digital watermark is an invisible mark embedded in a digital image which used for copyright protection. In this paper, we propose a new optical watermarking system. A optical watermarking system is applied for digital watermarking by phase hologram and Mach-Zehnder interferometer. A optical watermarking technique to be hidden is phase modulated in a random patten, and its Fourier-transformed hologram image is superposed on a content image. The autentication information extract by using Mach-zehnder interferometer.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.211-213
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• 2009

Derivation of the phase error of hologram due to imperfection of a wave plate and analysis of the effect of phase error on 3-D image reconstruction of hologram are prexented.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.4
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• pp.1-9
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• 2017

In this Paper, Double Encryption Technology Based on Phase-Shifting Digital Holography and Digital Watermarking is Proposed. For the Purpose, we First Set a Logo Image to be used for Digital Watermark and Design a Binary Phase Computer Generated Hologram for this Logo Image using an Iterative Algorithm. And Random Generated Binary Phase Mask to be set as a Watermark and Key Image is Obtained through XOR Operation between Binary Phase CGH and Random Binary Phase Mask. Object Image is Phase Modulated to be a Constant Amplitude and Multiplied with Binary Phase Mask to Generate Object Wave. This Object Wave can be said to be a First Encrypted Image Having a Pattern Similar to the Noise Including the Watermark Information. Finally, we Interfere the First Encrypted Image with Reference Wave using 2-step PSDH and get a Good Visible Interference Pattern to be Called Second Encrypted Image. The Decryption Process is Proceeded with Fresnel Transform and Inverse Process of First Encryption Process After Appropriate Arithmetic Operation with Two Encrypted Images. The Proposed Encryption and Decryption Process is Confirmed through the Computer Simulations.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2914-2916
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• 1999

A power distribution facility map is composed of distribution facility information regions, cadastral regions and grid lines. In this map, our goal is automatic interpretation of power distribution region. For the goal, it is the first work to extract the power distribution facility region. In this paper, we propose a method to extract power distribution facility regions. The proposed method is consist of two phases, binarization phase and extending phase. The first phase generate a power distribution facility image using threshold value. The image contains many part of power distribution facility regions, but not all. The second phase extends thinned image which is generated by appling thinning operator to the power distribution facility image.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.87-94
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• 2005

A computer code for Electrical Capacitance Tomography (ECT) is developed to sense the cross sectional phase distribution of two-phase flow in the rectangular pipe in which the tomography sensor furnished by the insulated wall, electrodes, and electric field screen. The computer code had two steps for the image reconstruction. In the forward projection step, the sensitivity matrix was constructed based on the electric field calculated by the finite difference method. In the backward projection step, the sensitivity matrix and the measured capacitances were used to reconstruct the cross sectional image. Several algorithms including LBP, TR, ITR, and PLI were employed to find the proper one for the two-phase flow analysis. Since the dielectric constant of the water in two-phase flow is sensitive to the thermal parameter such as, temperature and pressure, the developed code was evaluated to find their accuracy, speed of calculation, and sensitivity to the variation of the dielectric constant. It was found that the iterative methods are superior to the direct methods for the image reconstruction, and the PLI method was the best in the variation of the dielectric constants.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.625-628
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• 2007

We present an efficient and robust technique to estimate the velocity of moving targets from a single SAR image. In SAR images, azimuth image shift is a well known phenomenon, which is observed in moving targets having slant-range velocity. Most methods estimated the velocity of moving targets from the distance difference between the road and moving targets or between ship and the ship wake. However, the methods could not be always applied to moving targets because it is difficult to find the road and the ship wake. We adopted a method estimating the velocity of moving targets from azimuth differentials of range-compressed image. This method is based on an assumption that Doppler center frequency shift of moving target causes a phase difference in azimuth differential values. The phase difference is linearly distorted by Doppler rate due to the geometry of SAR image. The linear distortion is eliminated from phase removal procedure, and the constant phase difference is estimated. Finally, range velocity estimates for moving targets are retrieved. This technique is tested using an ENVISAT ASAR image in which several unknown ships are presented. The theoretical accuracy of this technique is discussed by SAR simulation. The advantages and disadvantages of this method over the conventional method are also discussed.