HDR Imaging for the Contrast Amplification in Photomicrography

Abstract

In order to enhance visualization under a microscope of very low contrast cells, cell staining technique can be used to increase the contrast in the photomicrography. However, cell preparation process is complicated because it depends on several types of staining media, which can be used for a different purpose. Here we investigate the contrast boosting in photomicrography of low contrast cells such as orchid root, onion root, sporangium of Psilotum nudum and butterfly wings by using high dynamic range (HDR) image processing. HDR techniques record an extended dynamic range by composing and tone mapping of three images with different exposures. As a result, HDR technique can increase the fine details within the specimen both in dark and bright areas. Thus the overall contrast of the HDR images is enhanced significantly about 4.5 times by average when comparing to the normal images and about 3.5 times when comparing to the images of stained cells. Keywords: Image Processing, Contrast, Photomicrography, High Dynamic Range, Microscope