The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform
Iej Ingrid Heynderickx - One of the best experts on this subject based on the ideXlab platform.
-
stroboscopic effect contrast threshold function and dependence on Illumination level
Journal of The Optical Society of America A-optics Image Science and Vision, 2018Co-Authors: Malgorzata Perz, Dragan Sekulovski, Imlc Ingrid Vogels, Iej Ingrid HeynderickxAbstract:The stroboscopic visibility measure (SVM) is a method used to quantify the stroboscopic effect visibility in general Illumination Application. SVM has been defined previously based on a limited number of frequencies and participants. To validate and extend SVM, five perception experiments are presented, measuring the visibility threshold of light waveforms modulated at several frequencies, conducted in two different labs. A power function is fitted through the aggregated results to develop a stroboscopic effect contrast threshold function for a “standard observer,” which can be used to normalize SVM. An additional experiment shows the dependency on Illumination level, extending the validity of SVM to other Applications.
Wei Yan - One of the best experts on this subject based on the ideXlab platform.
-
experimental investigation on the performance characteristics of white leds used in Illumination Application
Power Electronics Specialists Conference, 2007Co-Authors: Jianmin Zhou, Wei YanAbstract:The LEDs lamps' high efficiency, long life time and energy saving potential have made them emerge as a new Illumination lighting source. The temperature in the p-n junction can be considered to have a linear relationship with the forward current. Therefore, a proper current regulation strategy is important to alleviate the light output degradation and to maximize the useful life of high power LEDs. This paper presents an extensive experimental investigation on the influence of different current regulation modes on the light output degradation and lifetime of LEDs. It has been found that pulsed current regulation mode may be the optimal regulation mode for maximizing the useful lifetime of power LEDs.
Ludovic Macaire - One of the best experts on this subject based on the ideXlab platform.
-
reflectance estimation from multispectral linescan acquisitions under varying Illumination Application to outdoor weed identification
Sensors, 2021Co-Authors: Anis Amziane, Olivier Losson, Benjamin Mathon, Aurelien Dumenil, Ludovic MacaireAbstract:To reduce the amount of herbicides used to eradicate weeds and ensure crop yields, precision spraying can effectively detect and locate weeds in the field thanks to imaging systems. Because weeds are visually similar to crops, color information is not sufficient for effectively detecting them. Multispectral cameras provide radiance images with a high spectral resolution, thus the ability to investigate vegetated surfaces in several narrow spectral bands. Spectral reflectance has to be estimated in order to make weed detection robust against Illumination variation. However, this is a challenge when the image is assembled from successive frames that are acquired under varying Illumination conditions. In this study, we present an original image formation model that considers Illumination variation during radiance image acquisition with a linescan camera. From this model, we deduce a new reflectance estimation method that takes Illumination at the frame level into account. We experimentally show that our method is more robust against Illumination variation than state-of-the-art methods. We also show that the reflectance features based on our method are more discriminant for outdoor weed detection and identification.
Malgorzata Perz - One of the best experts on this subject based on the ideXlab platform.
-
stroboscopic effect contrast threshold function and dependence on Illumination level
Journal of The Optical Society of America A-optics Image Science and Vision, 2018Co-Authors: Malgorzata Perz, Dragan Sekulovski, Imlc Ingrid Vogels, Iej Ingrid HeynderickxAbstract:The stroboscopic visibility measure (SVM) is a method used to quantify the stroboscopic effect visibility in general Illumination Application. SVM has been defined previously based on a limited number of frequencies and participants. To validate and extend SVM, five perception experiments are presented, measuring the visibility threshold of light waveforms modulated at several frequencies, conducted in two different labs. A power function is fitted through the aggregated results to develop a stroboscopic effect contrast threshold function for a “standard observer,” which can be used to normalize SVM. An additional experiment shows the dependency on Illumination level, extending the validity of SVM to other Applications.
Zhang Guoqi - One of the best experts on this subject based on the ideXlab platform.
-
a review of passive thermal management of led module
Journal of Semiconductors, 2011Co-Authors: Ye Huaiyu, Sau Koh, Henk Van Zeijl, A W J Gielen, Zhang GuoqiAbstract:Recently, the high-brightness LEDs have begun to be designed for Illumination Application. The increased electrical currents used to drive LEDs lead to thermal issues. Thermal management for LED module is a key design parameter as high operation temperature directly affects their maximum light output, quality, reliability and life time. In this review, only passive thermal solutions used on LED module will be studied. Moreover, new thermal interface materials and passive thermal solutions applied on electronic equipments are discussed which have high potential to enhance the thermal performance of LED Module.
