透射光源下提升图像对比度的照明系统

针对微观驱替实验中使用点光源或漫射光照明的方法无法采集到清晰图像,本文通过对明场照明和暗场照明效果的分析,利用透射式柯拉照明原理设计了新的照明系统,在照度均匀的同时大幅提升了采集到的图像的对比度。由凸透镜对光路的作用,推导出柯拉照明的照度分布,讨论了影响照度均匀分布的因素;推演出了照明系统参数设计的依据,使系统的照度分布均匀。实验证明了本文设计的照明系统的有效性,有较高的推广价值。

Transillumination system used to improve the contrast of image

The micro displacement experiment,which uses glass etching model to simulate the structure of rock pore,is an important means to study the distribution of remaining oil.The contrast of glass etching model is very low,which means it is hard to get a clear image of the ultra-low contrast pore-edges by using the macro lens and diffuse lighting.It needs to alter the lighting system to improve the contrast of the captured image in the premise of uniform illumination.By studying the effect of illumination light on image acquisition quality,this article designs a new illumination system based on transmissive Kohler illumination to significantly improve the contrast of the pore-edges in the acquired image.This article also derives the intensity distribution of Kohler illumination and discusses the influence factors of evenly distributed illuminance,and deduced the design basis of parameters in the lighting system to make the system′s illumination uniform.It is verified through experiment that the design of this paper is effective:the illumination distribution is uniform and the contrast of the acquired image is significantly enhanced.There lies a high promotional value of the new system.