基于液晶局部选通系统的硬件算法的研究

鉴于CCD相机在强光照射时会产生光晕,CCD敏感面像素之间互相影响,进而导致成像模糊不清,提出一种克服光晕现象的像质增强算法.利用HTPS(高温聚硅)液晶具有可实时控制各像素光透过率的特性,使液晶和主CCD由光纤光锥进行像素一对一耦合.用Cyclone II芯片作为图像处理单元,测光CCD采集图像信息,控制液晶改善图像质量.实验结果表明,该系统能够精确控制HTPS液晶上每个像素的透过率,使CCD相机能在强光下正常成像,其灰度分辨能力提高了1倍,从而提高了图像的清晰度.

Hardware algorithm based on liquid crystal partial gating image system

Since the CCD camera produces the halo while highlight is shining on it, the pixels on the CCD sensitive plane interacts on each other, and then the image blur follows next, an image improvement algorithm for overcoming the phenomenon of the halo is proposed. With the characteristic that the HTPS liquid crystal could perform the real-time control of the light transmissibility of each pixels, the pixels on the liquid crystal and main CCD are coupled one by one by optical fiber tapers. The image information gathered by a photometric CCD is processed by Cyclone II (core of the image processing unit). The liquid crystal is controlled by Cyclone II for improving the image quality. The PAL signal is gathered by the video capture chip. The Y channel gray scale information can be adjusted by the empirical formula and the output signal is transformed to VGA format. The experiment indicates that this system can precisely control the light transmissibility of each pixel on HTPS liquid crystal, entrusts the CCD camera with the ability to image normally under the highlight, and increases the resolution of the camera by a factor of two.