Estimation of supplemental lighting efficiency based on PPFD distribution on the canopy surface
Estimation of supplemental lighting efficiency based on PPFD distribution on the canopy surface
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DOI：
10.2480/agrmet.69.2.1
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发表时间：
2013-01-01
影响因子：
1.3
通讯作者：
Shigemoto, Chiaki
中科院分区：
文献类型：
--
作者：
Ibaraki, Yasuomi;Shigemoto, Chiaki
提出了基于人工光下冠层表面光合光子通量密度（PPFD）分布的补光效率评价标准，并讨论了基于反射图像估算冠层表面PPFD分布的可能性。利用带有蓝绿带通滤光片的数码相机从三个方向采集了不同人工光照条件下植物冠层表面的反射图像。在冠层上的一个点处通过量子传感器与成像同时测量PPFD，并且结果用于确定回归模型以从图像的像素值估计叶片上的PPFD。将伽马校正后的像素值直方图转换为PPFD直方图。直方图模式依赖于光源和冠层结构。从图像估计的直方图可以描述差异，显示接近测量值的平均值和变异系数（CV）。根据直方图计算出所有被照射叶片的每单位功耗（IPPC）的综合PPFD，作为评价补充照明效率的标准。其效率还取决于光源、冠层结构和距冠层表面的距离。在每种情况下，估计的效率与测量值大致一致。这些结果表明，基于反射图像的光强度分布的估计可以用于简单的评估的效率的补充照明。
Criteria for evaluation of the efficiency of supplemental lighting based on photosynthetic photon flux density (PPFD) distribution on a canopy surface under artificial light were proposed, and the possibility of a reflection-image-based estimation of PPFD distribution on the canopy surface was discussed. Reflection images of plant canopy surfaces under various artificial lighting conditions were acquired from three directions with a digital camera equipped with a blue-green band-pass filter. PPFD was measured at one point on the canopy by a quantum sensor simultaneously with imaging, and the result was used to determine a regression model to estimate PPFD on leaves from pixel values of the image. The histogram of pixel values after gamma correction was converted into a PPFD histogram. The histogram pattern depended on the light source and canopy structure. Histograms estimated from images could depict the differences, showing mean values and coefficients of variation (CV) close to the measured values. Integrated PPFD over all illuminated leaves per unit power consumption (IPPC) was calculated from the histogram as a criterion for evaluating the efficiency of supplemental lighting. The efficiency also depended on the light source, canopy structure, and distance from the canopy surface. The estimated efficiency approximately agreed with the measured value in each case. These results suggest that reflection-image-based estimation of light intensity distribution can be used for simple evaluation of the efficiency of supplemental lighting.