用赞赏的眼光去看待玛蒂尔德

多年来 ,人们对莫泊桑的《项链》中的女主人公玛蒂尔德的看法贬多于褒 ,评论者给她定性为爱慕虚荣、追求享乐的小资产阶级妇女形象。这样的判定是不够妥贴和全面的。评价一个人 ,不能用静止的眼光 ,而应该用发展的眼光着重看其纵向的变化。因此 ,玛蒂尔德在丢失项链之后 ,所表现出的诚实善良、坚强不屈、坚韧不拨的品质更值得我们赞赏     

Advanced optics in a jellyfish eye

Cubozoans, or box jellyfish, differ from all other cnidarians by an active fish-like behaviour and an elaborate sensory apparatus. Each of the four sides of the animal carries a conspicuous sensory club (the rhopalium), which has evolved into a bizarre cluster of different eyes. Two of the eyes on each rhopalium have long been known to resemble eyes of higher animals, but the function and performance of these eyes have remained unknown. Here we show that box-jellyfish lenses contain a finely tuned refractive index gradient producing nearly aberration-free imaging. This demonstrates that even simple animals have been able to evolve the sophisticated visual optics previously known only from a few advanced bilaterian phyla. However, the position of the retina does not coincide with the sharp image, leading to very wide and complex receptive fields in individual photoreceptors. We argue that this may be useful in eyes serving a single visual task. The findings indicate that tailoring of complex receptive fields might have been one of the original driving forces in the evolution of animal lenses.     

一种改进的基于几何特征的人眼定位方法

针对灰度图像,提出一种改进的基于人眼几何特征的实现人眼快速定位的方法.先对人脸进行预处理,再根据人眼在二值图像中的几何位置特征制定人眼判定规则并粗估计图像分割的灰度门限所在范围,在该范围内通过递增灰度门限的方法,在不同灰度门限下的人脸二值图像中寻找符合规则的人眼黑块,最后通过二维相关系数来验证.抽取ORL人脸图库中24人的图片进行实验,结果比未经预处理的图片准确率提高了15%,从而证明这种算法是行之有效的.