A new type homogeneous planar PC （photoelectric converter） on the basis of multijunction semiconductor n＋-p-p＋-n＋-p-p＋-...-n＋-p-p＋ structure has been investigated. The entire structure is a cascade PC consisti...A new type homogeneous planar PC （photoelectric converter） on the basis of multijunction semiconductor n＋-p-p＋-n＋-p-p＋-...-n＋-p-p＋ structure has been investigated. The entire structure is a cascade PC consisting of a number of elements of the structure--single PCs connected in series and illuminated by light that has consistently passed through the previous semiconductor layers. The theory of converter of both monochromatic and solar radiation has been developed and the limiting values of their photoelectric and power characteristics have been determined, including the optimal thickness and number of single PCs layered on a base PC, their spectral sensitivity, current-voltage characteristics and efficiency. The open-circuit voltage grows practically linearly with the number of elements in the cascade. The top efficiency limit for a certain optimal elements number reaches its maximum that exceeds considerably that of the base PC, especially in the range of low collecting coefficient of charge carriers in the base PC.展开更多
文摘由于高分辨率全色影像(简称"高分影像")中的信息高度细节化,再加上噪声的影响,会导致传统基于纹理特征的居民地提取方法效果不理想。为此,提出一种基于小波纹理和基元合并的居民地提取方法。首先,利用结合小波变换(wavelet transform,WT)的分形网络进化算法(fractal net evolution approach,FNEA)获取初始基元,并对基元的多尺度小波纹理进行分析;然后,在人工给定种子基元的基础上合并具有相似纹理的基元;最后,对基元合并的结果进行数学形态学修整,得到居民地区域。利用天绘一号(TH-1)全色影像对所提方法进行验证及对比分析的结果表明,该方法对高分影像中的街区式居民地可取得较高的提取精度和计算效率。
文摘A new type homogeneous planar PC （photoelectric converter） on the basis of multijunction semiconductor n＋-p-p＋-n＋-p-p＋-...-n＋-p-p＋ structure has been investigated. The entire structure is a cascade PC consisting of a number of elements of the structure--single PCs connected in series and illuminated by light that has consistently passed through the previous semiconductor layers. The theory of converter of both monochromatic and solar radiation has been developed and the limiting values of their photoelectric and power characteristics have been determined, including the optimal thickness and number of single PCs layered on a base PC, their spectral sensitivity, current-voltage characteristics and efficiency. The open-circuit voltage grows practically linearly with the number of elements in the cascade. The top efficiency limit for a certain optimal elements number reaches its maximum that exceeds considerably that of the base PC, especially in the range of low collecting coefficient of charge carriers in the base PC.
