Complex-wave retrieval based on blind signal separation

In the process of the reconstruction of digital holography, the traditional methods of diffraction and filtration are commonly adopted to recover the original complex-wave signal. Influenced by twin-image and zero-order terms, the above-mentioned methods, however, either limit the field of vision or result in the loss of the amplitude and phase. A new method for complex-wave retrieval is presented, which is based on blind signal separation. Three frames of holograms are captured by a charge coupled device (CCD) camera to form an observation signal. The term containing only amplitude and phase of complex-wave is separated, by means of independent component analysis, from the observation signal, which effectively eliminates the zero-order term. Finally, the complex-wave retrieval of pure phase wavefront is achieved. Experimental results show that this method can better recover the amplitude and phase of the original complex-wave even when there is a frequency spectrum mixture in the hologram.     

让珠心算走进新课程推动基础教育的发展

进入21世纪以来，当中国基础教育高举全面推进素质教育的旗帜，为实施科技兴国战略切实履行“奠基工程”职责的时候，基础教育课程改革走进了校园，走进了师生的生活，受到了教育者和家长们前所未有的重视。早在1985年邓小平同志就曾指出：“现在小学一年级的娃，经过9年的学校教育，将成为21世纪大业的生力军。中央提出要以极大的努力抓教育，并且从小学抓起……”可见，基础教育是关系国家、民族前途和命运的千秋大业。