• 한국지능시스템학회논문지
• /
• 제26권4호
• /
• pp.321-326
• /
• 2016

본 논문에서는 휴대용 휘도측정시스템의 측정위치기반 휘도보정알고리즘을 제안한다. 측정거리와 측정각도에 따라 휘도 값은 변화하며, 측정거리와 측정각도를 고려한 알고리즘을 적용하여 기존에 개발된 영상기반 휘도측정시스템의 오차를 개선한다. 카메라 영상기반의 휘도 정보를 정확하게 획득하는 면측정방법을 제안하기 위해서 점휘도계로 측정대상물과의 측정각도에 따른 휘도 값의 변화를 측정한다. 측정거리, 측정각도와 휘도 값 간의 연관성을 수식으로 나타내었고, 측정위치를 고려한 알고리즘을 제안한다. 실험용 간판을 대상으로 점휘도계와 제안한 휘도측정시스템을 비교 평가 실험하고 제안한 휘도측정시스템의 성능을 검증하였다.

• 한국지능시스템학회논문지
• /
• 제24권4호
• /
• pp.424-429
• /
• 2014

본 논문에서는 발광광고물의 휘도를 측정하는 영상기반 휘도측정시스템을 제안한다. 제안하는 휘도측정시스템은 DSLR 카메라의 영상을 이용하여 점휘도계의 효율성과 면휘도계의 휴대성 및 경제성의 단점을 보완하며, 대상의 전체적인 휘도를 측정하는 시스템으로 영상을 입력받아 휘도분석 알고리즘을 통해 실시간으로 휘도값이 출력되도록 설계하였다. 측정 대상인 발광광고물은 설치 위치, 크기, 모양이 다양하며, 발광광고물의 휘도는 측정 거리, 각도, 색 등 다양한 조건에 따라 측정값이 달라진다. 따라서 정확한 휘도를 측정하기 위하여 측정대상물과의 거리에 따른 휘도값의 변화를 측정하였고, 측정 거리가 증가하면 휘도값이 변화하는 것을 고찰하였다. 실험을 통하여 측정 위치와 휘도값의 연관성을 수식으로 나타내었고, 제안한 방법을 평가하기 위해 점휘도계를 이용한 측정값과 비교 실험을 진행하였다.

• 한국도로학회논문집
• /
• 제18권6호
• /
• pp.145-152
• /
• 2016

OBJECTIVES : Visibility at night can be improved by using retroreflection for short distances and phosphorescent line markings for long distances. In this study, we analyzed the characteristics of the phosphorescent line marking through a laboratory luminance test. Field performance analysis was performed through tests conducted on the road. We also examined the luminance measurement methods using the digital image obtained during the phosphorescent visibility evaluation. METHODS : In this study, the laboratory luminance test of the phosphorescent line marking was conducted using seven specimens to characterize the luminance changes according to the type of the glass beads, the thickness of the phosphorescent line marking, and the brightness and irradiation time of the light source. Phosphorescent and general line markings were made at 150 m to investigate the field luminance performance. A preliminary review of the luminance measurement methods was made using a digital image from a digital single-lens reflex (DSLR) camera. The measured luminance ratio of the general and the phosphorescent line markings was compared with the calculated luminance ratio using luminance analysis. RESULTS : Through the laboratory luminance test, it was seen that the change in luminance, which corresponds to the brightness of the light source, appears large but the influence of the thickness and irradiation time is low. The field performance test of the phosphorescent line marking conducted on the road involved measuring the luminance on the day the marking was made and 7 days after the marking was made. The luminance was found to be $190mcd/m^2$ at 30 min after sunset and approximately $10-12mcd/m^2$ 4h after sunset. The results of the luminance test were captured using a digital image for each time group. The luminance ratio of the phosphorescent line marking, when compared to that of the general line marking, showed a similar trend within a 13% maximum error. Additionally, when this luminance ratio is compared to the direct field measurement, it could be confirmed that the luminance ratio, as captured in the digital image, showed a similar tendency. CONCLUSIONS : 1) The change in luminance corresponding to the brightness of the light source is significant in comparison with that corresponding to the thickness and the irradiation time. In addition, the results of the field test for the phosphorescent line marking satisfied the phosphorescent fire protection standard. 2) We examined the validity of the luminance measurement method using a digital image and we concluded that the change in the luminance ratio shows a similar tendency in both the cases. The results can form the basis for luminance measurement methodology for the construction and maintenance of phosphorescent line markings.

• 조명전기설비학회논문지
• /
• 제23권2호
• /
• pp.10-17
• /
• 2009

야간경관에는 수많은 광원(光源)에 의해 다양한 휘도(Luminance)로 나타난다. 휘도를 측정하는데 있어 측정 범위가 한정되어 있다. 기존의 휘도계를 이용한 측정방식은 하나의 점을 통한 점(Point)측정방식이기 때문이다. 야간경관의 휘도를 쉽고 편리하게 정보를 얻고자 휘도 측정에 있어 DSLR 카메라를 이용하게 되었다. 현재 광학의 기술로 인해 디지털 카메라의 활용가치가 매우 크며 쉽게 이미지데이터를 얻을 수 있다. 이러한 디지털 이미지로부터 야간경관의 휘도 분석과 DSLR 카메라의 면(Scene) 측정방식을 통한 휘도 측정 기법에 대해 제안하고자 한다.

• 한국디지털건축인테리어학회논문집
• /
• 제12권3호
• /
• pp.81-89
• /
• 2012

Luminance is the most important quantity in lighting design and illuminating engineering. There are three methods for measuring luminance; using a conventional luminance meter, through the illuminance measurement and subsequent calculations and using digital imaging photometer. Recently, HDRI(High Dynamic Range Imaging) technique introduces a new method of capturing luminance values in a lighting environment. The radiance maps from HDRI are commonly used as visual environment maps for lighting analysis applications. For the HDRI, HDR software is needed to create HDR image. Currently, there is number of HDR software available. The purpose of this paper is to investigate whether a luminance map can be accurately captured by the various types of HDR software which include HDR Shop and Photoshop. To accomplish this goal a set of experiments was conducted. In order to assess the luminance values of the HDR image from HDR software, the values had to be compared to the ones obtained with conventional methods of luminance measurement.

• 한국디지털건축인테리어학회논문집
• /
• 제12권2호
• /
• pp.33-38
• /
• 2012

The purpose of luminance measurement in lighting design of urban scale is to prevent light trespass and light pollution, caused by over-bright. Specially, the illumination of road, tunnel and sports complex as urban infrastructure is measured by international standard for illuminance and luminance. It has been used the spot luminance meter and the image photometer to define the characteristics of qualitative and quantitative in exterior lighting. This study introduced the concept of HDR Image, procedure of HDR Image creation and analysis. Applications of HDR Image, particularly within the apartment building exterior lighting design analysis, have been demonstrated. The procedure proposed in this study is a affordable method that is useful for the assessment of luminance distribution in the scene with electric light. It also provides a measurement capability with the high resolution luminance data within a large field of view efficiently and quickly, which is not possible to achieve with a luminance meter.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.991-994
• /
• 2009

This paper reports of camera detection of Mura. The type, location, size, orientation and amplitude are found. As the luminance variation in Mura is down to less than app. 0.3 %, measurement apparatus, techniques and algorithms are developed to measure low noise data and to extract the Mura from data with the residual noise in the same magnitude as the Mura.

• 조명전기설비학회논문지
• /
• 제26권10호
• /
• pp.1-8
• /
• 2012

To suggest lighting regulations to prevent light pollution, domestic and international standards were analyzed and the luminance of outdoor signboards of main street at night was measured. In addition, to regulate the methods of luminance measurement, experiments on the measuring distance and direction from the signboards were conducted. The regulations were set as maximum luminance for outdoor signboard lightings of channel letter type, and limitations were suggested on each of the four lighting zones.

• 조명전기설비학회논문지
• /
• 제26권1호
• /
• pp.1-7
• /
• 2012

As the standard lighting required in the threshold zone of a road tunnel is determined by the enough contrast. Lighting design, therefore, must be determined by the calculation method of threshold luminance based on the adaptation luminance of the driver approaching the tunnel. The veiling luminance and the luminance in the access zone were measured at different time and in different weather using the veiling luminance method, a kind of perceived contrast methods, and the L20 method when the range of vision was 20 degrees. On the basis of the measured data each threshold luminance was calculated and its results were analyzed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.1370-1373
• /
• 2008

This paper introduces a novel display measuring instrument that allows accurate, spectro-radiometric measurement of the complete viewing cone while the measuring time is similar to that of a CCD camera with transform lens optics. Actually the new instrument, named POLYGONIOSCOPE, is orders of magnitude faster compared to a conventional spot spectrometer.