Combined application of extended depth of field imaging, image stitching and polarized microscopy techniques in identification of Spatholobus suberectus

OBJECTIVE: As traditional techniques for microscopic identification of Chinese medicines currently lack objective and high-quality reference images, here we developed a systemic procedure to be used in microscopic identification of Chinese medicines, which would lead to more objective, effective and accurate identification process. METHODS: Spatholobi Caulis (Jixueteng in Chinese) was used as the specimen in the development of such procedure. Jixueteng samples were microscopically examined in bright- and dark-field microscopy. Microscopic images were obtained by regular, EDF, and image stitching techniques. RESULTS: The microscopic images of the characteristics in pulverized Jixueteng were captured, thanks to EDF imaging and image stitching techniques which allowed the detailed and full sighting of each characteristic to be obtained simultaneously. Different layers in anatomical transverse section, including cork, phelloderm, cortex, phloem, cambium, xylem and pith, were distinctively observed. Moreover, by comparing images of bright- and dark-field microscopy, birefringent and non- birefringent components could readily be distinguished. CONCLUSION: With application of the developed procedure, high-definition, panoramic and microscopic images were acquired, which could be used as the reference images for microscopic identification of Chinese medicines.