Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requir...Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.展开更多
A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of t...A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of the integrating sphere and requirement of the strip uniform illumination region. This system was called dome light. White light LED array light sources were used for uniform illumi- nation. The LEDs were filtrated to composite array light source based on coefficient of variation of a single LED. The standard white board and SG color checkers were used in the line-scan CCD imaging experiments under the dome light and ordinary illumination light source. The average color difference （AE） of SG color checkers in CIELAB space was 2. 091 under the dome light and 2. 286 under ordinary illumination light source respectively. Experimental results indicate that the dome light can satisfy illumination uniformity and color rendering consistency for line-scan CCD and provide a standard light source for uniform calibration of different cameras.展开更多
随着无人机技术的发展,利用无人机影像进行地形三维重建和全景影像生成,已经越来越普及。然而由于无人机影像拍摄时角度、光照条件、相机设置等具有不一致性,多视角无人机影像间通常存在一定的颜色差异。颜色差异的存在,会影响多视影像...随着无人机技术的发展,利用无人机影像进行地形三维重建和全景影像生成,已经越来越普及。然而由于无人机影像拍摄时角度、光照条件、相机设置等具有不一致性,多视角无人机影像间通常存在一定的颜色差异。颜色差异的存在,会影响多视影像密集匹配的精度,从而影响三维几何模型的精度。此外,颜色差异也会影响全景影像和纹理模型的视觉效果,拼接后影像及纹理模型上易出现“鬼影”及颜色拼接缝等问题。为解决该问题,本文提出一种无人机多视影像颜色一致性处理方法。首先,采用Structure from Motion (SfM)方法获取无人机影像间的所有匹配点;其次,构建并简化多视角无人机影像拓扑关系图;最后,基于颜色对应关系全局优化所有影像的颜色映射模型,获得匀色后影像。通过真实数据集进行实验,验证了本文提出的色彩一致性处理方法的有效性。展开更多
基金the National Key R&D Program of China(2021YFB3501700,2023YFB3506600)National Natural Science Foundation of China(52202135,61975070,and 52302141)+5 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),International S&T Cooperation Program of Jiangsu Province(BZ2023007)Key Research and Development Project of Jiangsu Province(BE2023050,BE2021040)Natural Science foundation of Jiangsu Province(BK20221226)Graduate Research and Innovation Projects of Jiangsu Province(KYCX22_2845)Special Project for Technology Innovation of Xuzhou City(KC23380,KC21379,KC22461,and KC22497)Open Project of State Key Laboratory of Crystal Materials(KF2205).
文摘Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.
基金Supported by the National Natural Science Foundation of China(61078048)
文摘A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of the integrating sphere and requirement of the strip uniform illumination region. This system was called dome light. White light LED array light sources were used for uniform illumi- nation. The LEDs were filtrated to composite array light source based on coefficient of variation of a single LED. The standard white board and SG color checkers were used in the line-scan CCD imaging experiments under the dome light and ordinary illumination light source. The average color difference （AE） of SG color checkers in CIELAB space was 2. 091 under the dome light and 2. 286 under ordinary illumination light source respectively. Experimental results indicate that the dome light can satisfy illumination uniformity and color rendering consistency for line-scan CCD and provide a standard light source for uniform calibration of different cameras.
文摘随着无人机技术的发展,利用无人机影像进行地形三维重建和全景影像生成,已经越来越普及。然而由于无人机影像拍摄时角度、光照条件、相机设置等具有不一致性,多视角无人机影像间通常存在一定的颜色差异。颜色差异的存在,会影响多视影像密集匹配的精度,从而影响三维几何模型的精度。此外,颜色差异也会影响全景影像和纹理模型的视觉效果,拼接后影像及纹理模型上易出现“鬼影”及颜色拼接缝等问题。为解决该问题,本文提出一种无人机多视影像颜色一致性处理方法。首先,采用Structure from Motion (SfM)方法获取无人机影像间的所有匹配点;其次,构建并简化多视角无人机影像拓扑关系图;最后,基于颜色对应关系全局优化所有影像的颜色映射模型,获得匀色后影像。通过真实数据集进行实验,验证了本文提出的色彩一致性处理方法的有效性。
