• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.227-234
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• 1996

This paper is the study of the diffusion constant in order to calculate the percent oxygenation and percent blood volume using reflectance light within biological tissue. The diffusion constant play major role in percent oxygenation and percent blood volume and varies with the biological material such as hemolyzed blood, whole blood, dermis and epidermis in vivo tissue. The diffusion constant can be modeled to consist of a contribution from bloodless tissue and blood present in tissue. The reflectance light for experimental are red light of 660nm, infrared light of 880nm, green light of 569nm. The correlation between the diffusion constant and biological tissue was analyzed by the intensity of reflectance light at different depth within human limb. The reflectance light was changed in response to physiological changes within biological tissue. The data for diffusion constant were obtained at different depth beneath the surface of the skin and will be utilized to amen the percent oxygenation and percent blood volume.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.81-88
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• 1993

This paper is the study of the reflectance of light from biological tissue for red and Infrared wavelengths and relates the acquired reflectance data to expected physiological changes within the skin and muscle layers associated with heat and exercise. The instrument was disigned to collect data from the calf muscle in human subjects with probe located at the surface of skin. Rapid data acquisition method allowed monitoring of rapid changes in reflecttance due to a stimulus. This study demonstrates that changes in O2 saturation and blood fractional volume expected within the dermis and muscle layers were asserted by examining the slopes of the plotted index for heat and exercise. The results presented in thls study support the claim that reflectance can separately discriminate between changes of blood volume and oxygenation in muscle and in skin. The data demonstrate the ability to measure consistent changes In tissue optical properties during exercise and heat.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.205-212
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• 2013

Pain is one of the quite common symptoms in clinics and many treatment methods have been applied to relieve pain. Among the treatments, high-intensity light therapy for pain has been introduced, but this therapy has not been fully supported by confirmed efficacy due to the absence of quantitative assessments and treatment feedback data in real time. In this study, the evaluation of light distribution in tissue was performed with current high-intensity light sources quantitatively using light-tissue interaction simulations. The diffuse reflectance in tissue was generated using Monte Carlo simulation that traces photons as they undergo multiple scattering and absorption within each tissue layer (skin, fat, and muscle) and within multi-layered tissue. The results showed that the highest diffuse reflectance and the deepest penetration of tissue were achieved at ${\lambda}$=830 nm when compared with other wavelengths like ${\lambda}$=650 nm, 980 nm and 1064 nm.

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.265-274
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• 1994

This paper proposes a method of noninvasive reflectance light to measure the blood fractional volume (Vb) and oxygen saturation ($SO_2$) of biological tissue. We chose the red light of 660nm and infrared light of 880nm. In Vivo reflectance data were obtained by the physiological changes front the surface of the skin over the calf in human subject. The reflected light intensity from different layers within a biological tissue was measured by specially designed reflectometer to apply photon path diffusion model. The collected data represent the changes of blood (ractional volume and oxygen saturation at each reflected light wavelengths. The data evaluation was assessed by examining the slopes of the plotted indices for the changes in oxygen saturation and blood (ractional volume. The results presented in this paper claim that light reflectance can separately discriminate the change of blood volume and that of oxygenation in muscle and also in skin.

• 대한화장품학회지
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• 제42권1호
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• pp.45-55
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• 2016

빛은 피부에서 개개인마다 상이한 반사, 흡수 및 산란 등의 광학적 거동을 보여준다. 특히, 피부에서 빛의 반사는 분광반사율이라는 물리량 측정을 통해 개인의 피부 밝기지표로 널리 활용되어 왔다. 따라서 피부에서 빛의 반사 거동 연구는 개인 맞춤형 화장품, 특히 메이크업 제품 개발에 있어 좀 더 효율적인 처방 개선에 기여하거나 새로운 평가법에 활용될 수 있다. 본 연구에서는 Kubelka-Munk 모델을 이용하여 개인의 피부 특성에 따른 빛의 분광반사율 거동에 대해 다각적인 분석을 수행하였다. 또한, 상기 모델과 기존에 알려진 문헌 정보를 이용하여 개인의 피부 분광반사율에 영향을 줄 수 있는 피부 두께 및 헤모글로빈 등의 다양한 파라미터들에 대한 기여도 분석을 수행하였다. 이를 통해, 일반적인 여성의 피부에서의 분광반사율 이론치를 계산하였고, 분광반사율 실측을 통해 이론치와 실측치 간의 유사성을 확인하였다. Kubelka-Munk 모델을 이용한 피부 분광반사율 연구는 향후 새로운 개인 맞춤형 메이크업 화장품 개발에 유용하게 이용될 수 있을 것으로 사료된다.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.484-490
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• 2011

Defects exist underneath the fruit skin are not easily discernable by using conventional color imaging technique in the visible wavelength ranges. Development of sensitive detection methods for the defects is necessary to ensure accurate quality sorting of fruits. Hyperspectral imaging techniques, which combine the features of image and spectroscopy to acquire spatial and spectral information simultaneously, have demonstrated good potentials for identifying and detecting anomalies on biological substances. In this study, a high spatial resolution hyperspectral reflectance technique was presented as a tool for detecting bruises on apple. The two-band ratio (494 nm / 952 nm) and simple threshold methods were applied to investigate the feasibility of discriminating the bruises from sound tissue of apple. The pixel wise accuracy of the discrimination was 74%. The resultant images processed with selected wavebands and morphologic algorithm distinctively showed the early stages of bruises on apple which were not discernable by naked eyes as well as a conventional color camera. Results demonstrated good potential of the hyperspectral reflectance imaging for detection of bruises on apple.

• 대한화장품학회지
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• 제41권3호
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• pp.279-285
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• 2015

여성의 얼굴에 과색소침착이 발생하는 것은 불안감, 특히 미적인 요소에 있어서 많은 고민을 유발한다. 피부의 흑화는 자외선(UV)에 대하여 이를 방어하기 위한 기작으로 멜라닌의 양과 밀접한 관계가 있다. 이러한 피부의 구성성분을 관찰하기 위해, confocal scanning laser microscope (CSLM)은 피부에 직접 현미경 검사를 실시하여 어떠한 조직의 변화 없이 피부를 실시간으로 관찰할 수 있는 비침습적 이미지 장치이다. 본 연구에서는 자외선 조사를 통해 유도된 하박 내측 피부의 과색소침착을 유도하여, 다른 피부색을 평가하는 측정기기와 상관성을 분석하여, CSLM을 이용한 새로운 미백 평가방법을 제시하였다. CSLM을 활용한 미백 효능 평가법은 소비자가 보다 이해하기 쉽도록 미백 제품을 평가하는데 유용할 것으로 생각된다.