Fernández Ariel, Alonso Julia R, Flores Jorge L, Ayubi Gastón A, Di Martino J Matías, Ferrari José A
Instituto de Física, Facultad de Ingeniería, UdelaR, J. Herrera y Reissig 565, 11300 Montevideo, Uruguay.
Opt Express. 2011 Oct 10;19(21):21091-7. doi: 10.1364/OE.19.021091.
We present a novel optical method for edge enhancement in color images based on the polarization properties of liquid-crystal displays (LCD). In principle, a LCD generates simultaneously two color-complementary, orthogonally polarized replicas of the digital image used as input. The currently viewed image in standard LCD monitors and cell phone's screens -which we will refer as the "positive image or true-color image"- is the one obtained by placing an analyzer in front of the LCD, in cross configuration to the back polarizer of the display. The orthogonally polarized replica of this image -the "negative image or complementary-color image"- is absorbed by the front polarizer. In order to generate the positive and negative replica with a slight displacement between them, we used a LCD monitor whose analyzer (originally a linear polarizer) was replaced by a calcite crystal acting as beam displacer. When both images are superimposed laterally displaced across the image plane, one obtains an image with enhanced first-order derivatives along a specific direction. The proposed technique works under incoherent illumination and does not require precise alignment, and thus, it could be potentially useful for processing large color images in real-time applications. Validation experiments are presented.
我们提出了一种基于液晶显示器（LCD）偏振特性的彩色图像边缘增强新光学方法。原则上，LCD会同时生成用作输入的数字图像的两个颜色互补、正交偏振的副本。标准LCD显示器和手机屏幕中当前显示的图像——我们将其称为“正图像或真彩色图像”——是通过在LCD前放置一个检偏器获得的，该检偏器与显示器的后偏振器呈正交配置。该图像的正交偏振副本——“负图像或互补色图像”——被前偏振器吸收。为了生成正负副本并使它们之间有轻微位移，我们使用了一台LCD显示器，其检偏器（原本是线性偏振器）被用作光束位移器的方解石晶体所取代。当这两个图像在图像平面上横向错位叠加时，会得到一个沿特定方向一阶导数增强的图像。所提出的技术在非相干照明下工作，且不需要精确对准，因此，它在实时应用中处理大型彩色图像方面可能具有潜在用途。文中展示了验证实验。
