Improving rapidity of microbial counting with dark-field illumination and polarized light.

这项研究的目的是快速清点活细菌。为了实现快速计数，应在菌落还很小的时候找到微生物菌落。但琼脂的厚度干扰了拍摄高分辨率图像的精确对焦。因此，早期检测蜂群的最好方法之一是获得高对比度图像。TB对比度高，暗视照明效果好，先用偏振光和长波长光进行改善，考虑了暗视光照明的最佳要求，使所有底片的对比度高，亮度不均匀小。其次，比较了暗场照明与普通明场照明采集的大肠杆菌图像的对比度，前者约为后者的2~3倍。其次，由于使用p偏振光或长波长光与暗场照明一起使用的效果，两种对比度分别提高到约12~1.3倍和约1.5~1.8倍。然后，在从培养初期开始以固定间隔用CCD摄像机拍摄含有大肠杆菌的培养基板的实验中，对这几种方法的菌落计数时间进行了比较，结果表明，在暗场照明下的测量时间比以前的方法缩短了约3小时，使用p偏振光的测量时间进一步缩短了1小时。综上所述，本研究将以前需要的12小时左右的测量时间缩短为8小时。

The purpose of this research is enumerating viable bacteria rapidly. In order to realize rapid enumeration, microbial colonies should be found while colonies are still small. But thickness of an agar disturbs precise focusing to take high resolution images. So, one of the best way to detect colonies early is to get high contrast images. Tb get high contrast ratio, dark-sight illumination is effective, and polarized light and long wavelength light are also used to improve it First, the best requirements of dark-sight illumination are considered to get higher contrast ratio and less unevenness of brightness over all the media plate. Second, contrast ratios of acquired images with E.coli are compared using dark-field illumination with using common bright-field illumination, the former is about 2 to 3 times higher than the latter. Next, as the effect of using either p-polarized light or long wavelength light together with dark-field illumination, each contrast ratio is improved to about 12 to 1.3 times and about 1.5 to 1.8 times higher than that of without them. And then, in experiments to take images of media plate containing E.coli with a CCD camera at regular intervals from the initial stage of culturing, colony counting time with those methods are compared to one another As a result, measuring time is about 3 hours shorter with dark-field illumination than with the previous method, and further 1 hour is shortened by using p-polarized light. In conclusion, the previously needed about 12 hours of measuring time is shortened to 8 hours by this research.