In order to improve image quality, a novel Retinex algorithm for image enhancement was presented. Different from conventional algorithms, it was based on certain defined points containing the illumination information ...In order to improve image quality, a novel Retinex algorithm for image enhancement was presented. Different from conventional algorithms, it was based on certain defined points containing the illumination information in the intensity image to estimate the illumination. After locating the points, the whole illumination image was computed by an interpolation technique. When attempting to recover the reflectance image, an adaptive method which can be considered as an optimization problem was employed to suppress noise in dark environments and keep details in other areas. For color images, it was taken in the band of each channel separately. Experimental results demonstrate that the proposed algorithm is superior to the traditional Retinex algorithms in image entropy.展开更多
风力发电在我国能源结构中占比逐年攀升。对风能资源进行准确全面的评估是提升风电出力水平和消纳能力的先决条件。基于空间插值方法建立的高分辨率网格化风资源数据集,可对风资源进行大范围、格点化和精细化的有效评估。为提高风资源...风力发电在我国能源结构中占比逐年攀升。对风能资源进行准确全面的评估是提升风电出力水平和消纳能力的先决条件。基于空间插值方法建立的高分辨率网格化风资源数据集,可对风资源进行大范围、格点化和精细化的有效评估。为提高风资源数据集的准确性,文章提出了一种基于K-means++自适应的改进反距离加权插值方法(K-means++adaptive inverse distance weighted interpolation method,K-means++AIDW)。使用该方法对山东地区2022年全年109个国家级气象观测站点的风速实测数据进行处理,构建空间分辨率为9km×9km的网格点,使用风速实测数据逐小时对网格点进行插值填补,得到高分辨率的网格化风资源数据集。将插值后的结果与原始观测数据进行比较发现,与传统反距离加权法(inverse distance weighting,IDW)和Kriging插值方法相比,所设计的K-means++AIDW插值方法平均绝对误差较IDW方法降低了5.4%,较Kriging方法降低了7.8%;均方根误差较IDW方法降低了5.9%,较Kriging方法降低了8.1%,显示出其在整体误差控制上的优势。与空间分辨率0.25°×0.25°的再分析回算数据集ERA5(Fifth Generation of European Centre for Medium-range Weather Forecasts Atmospheric Reanalysis of the Global Climate)的风资源要素相比,所设计的K-means++AIDW插值数据集平均绝对误差和均方根误差平均降低了11.95%和10.07%,验证了所设计插值方法的准确有效性,以及生成的高分辨率网格化数据集的精准可靠性,可作为评估山东省的风能资源潜力的可靠数据基础,为风能资源管理和风电场选址等领域提供准确的数据支持。展开更多
基金Project(61071162) supported by the National Natural Science Foundation of China
文摘In order to improve image quality, a novel Retinex algorithm for image enhancement was presented. Different from conventional algorithms, it was based on certain defined points containing the illumination information in the intensity image to estimate the illumination. After locating the points, the whole illumination image was computed by an interpolation technique. When attempting to recover the reflectance image, an adaptive method which can be considered as an optimization problem was employed to suppress noise in dark environments and keep details in other areas. For color images, it was taken in the band of each channel separately. Experimental results demonstrate that the proposed algorithm is superior to the traditional Retinex algorithms in image entropy.
文摘风力发电在我国能源结构中占比逐年攀升。对风能资源进行准确全面的评估是提升风电出力水平和消纳能力的先决条件。基于空间插值方法建立的高分辨率网格化风资源数据集,可对风资源进行大范围、格点化和精细化的有效评估。为提高风资源数据集的准确性,文章提出了一种基于K-means++自适应的改进反距离加权插值方法(K-means++adaptive inverse distance weighted interpolation method,K-means++AIDW)。使用该方法对山东地区2022年全年109个国家级气象观测站点的风速实测数据进行处理,构建空间分辨率为9km×9km的网格点,使用风速实测数据逐小时对网格点进行插值填补,得到高分辨率的网格化风资源数据集。将插值后的结果与原始观测数据进行比较发现,与传统反距离加权法(inverse distance weighting,IDW)和Kriging插值方法相比,所设计的K-means++AIDW插值方法平均绝对误差较IDW方法降低了5.4%,较Kriging方法降低了7.8%;均方根误差较IDW方法降低了5.9%,较Kriging方法降低了8.1%,显示出其在整体误差控制上的优势。与空间分辨率0.25°×0.25°的再分析回算数据集ERA5(Fifth Generation of European Centre for Medium-range Weather Forecasts Atmospheric Reanalysis of the Global Climate)的风资源要素相比,所设计的K-means++AIDW插值数据集平均绝对误差和均方根误差平均降低了11.95%和10.07%,验证了所设计插值方法的准确有效性,以及生成的高分辨率网格化数据集的精准可靠性,可作为评估山东省的风能资源潜力的可靠数据基础,为风能资源管理和风电场选址等领域提供准确的数据支持。
