• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.139-146
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• 2016

Recently, popularity of 3D technology has been growing significantly and it has many application parts in the various fields of industry. In order to overcome the limitations of 2D machine vision technologies based on 2D image, we need the 3D measurement technologies. There are many 3D measurement methods as such scanning probe microscope, phase shifting interferometry, confocal scanning microscope, white-light scanning interferometry, and so on. In this paper, we have used the extended depth of focus (EDF) algorithm among 3D measurement methods. The EDF algorithm is the method which extracts the 3D information from 2D images acquired by short range depth camera. In this paper, we propose the EDF algorithm using the edge informations of images and the average values of all pixel on z-axis to improve the performance of conventional method. To verify the performance of the proposed method, we use the various synthetic images made by point spread function(PSF) algorithm. We can correctly make a comparison between the performance of proposed method and conventional one because the depth information of these synthetic images was known. Through the experimental results, the PSNR of the proposed algorithm was improved about 1 ~ 30 dB than conventional method.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.187-192
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• 2008

This study carried out researches on the techniques which are applicable to express sense of depth in the process of producing lofty image contents, and it's verification. Techniques for expression of sense of depth are how to use highlight and shadow, how to use depth of field and lenses, and how to use camera motion, zoom and dolly. For the practical application in all cases, I examine the preference frequency, and most of the pictures that techniques are adapted are selected. As a result we can verify the way of using lenses is the most convenient way in the expression of 'sense of depth'.

• Journal of Korea Water Resources Association
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• v.48 no.7
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• pp.535-543
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• 2015

Measurements of multiphase flows containing bubbles have been limited because most existing methods target one phase flows. Especially, multiphase flows with a high void ratio have been rarely successful in measurements due to the sudden change of density and thick interfaces between air and water. This study introduces two methods that are capable of measuring flow fields regardless of bubble void ratio, named bubble image velocimetry and bundle fiber optic flow meter. The calculation of the depth of field is suggested to reduce and estimate errors by perspective image velocimetry. The bundle fiber optic flow meter is designed to increase a measurement rate using many optical fibers with a thin diameter. The two methods measured bubble plumes to test reliability and the velocity measurements show good agreement. In addition a hydraulic jump, one of the multiple flows in rivers was measured to test applicability of the methods.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.57-66
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• 2011

At this time, digital cameras are used in art and forensic science. However, the digital camera has some limitations which need to understand of photograph and lighting. It is a useful paper to make an infrared flatbed scanner. The following processes offer an infrared flatbed scanner development. First, the infrared flatbed scanner changes visible fluorescent lamp to infrared LED. Second, it equips a long-pass filter, which is available to pass over 810nm wavelength, on the glass to complete the optimal infrared flatbed scanner. In addition, it must copy from digital camera to computer directly. The infrared digital camera has disadvantage to always irradiate infrared lamp. Because of difference between visible length and infrared length characteristic, they have different focal distance. This devised scanner for solving mentioned problems does not need to irradiate infrared lamp, and there is not a problem about focal point because the depth of field of flatbed scanner is minimum 2mm. Lastly, the infrared flatbed scanner can make high resolution which is 12,800dpi unlike digital camera. Accordingly, the infrared scanner looks forward to be used in many field of study.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.1-8
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• 2017

A method for inspecting defects in display substrates utilizing Fourier optics is proposed in this paper. A cost-effective inspection system can be realized with the proposed method, because it does not require a high-magnification microscope. Also, the proposed method can avoid tight tolerance for variations in displacement between substrate and camera, which is stems from shallow depth of field of the high-magnification microscope. In addition, possible damage caused by collisions between substrate and the inspection equipment can be avoided. The decision algorithm can be simpler than for a conventional inspection system, because spatial shift of periodic substrate patterns does not affect the intensity distribution of the diffracted light, by the Fourier transform property. The proposed method is explained with numerical studies, and experiments are carried out to check its feasibility for color-filter substrates of a liquid-crystal display.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.57-65
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• 2014

The role of sound in producing 3D animation clip is one of the important factor to maximize the immersive effects of the scene. Especially interaction between video and sound makes the scene expressions more apparent, which is diversely applied in video production. One of these interaction techniques, the out-focussing technique is frequently used in both real video and 3D animation field. But in 3D animation, out-focussing is not easily implemented as in music videos or explosion scenes in real video shots. This paper analyzes the sound data to synchronize the depth of field with it. The novel out-focussing technique is proposed, where the object's field of depth is controlled by beat rhythm in the sound data.