An Automatic Measurement Algorithm for the Diameters of Carbon Nanotubes by Using Image Processing

We propose an automatic measurement algorithm for the diameters of carbon nanotubes (CNTs) electron microscopy images by using image processing. In the algorithm, Otsu's method (discriminant analysis method) was employed to determine automatically the threshold for image binarization. Proposed algorithm provides the numerous values of diameters detected by horizontal and vertical scans for the binary images. The diameter measurements using developed program were carried out for the multi-walled CNTs (MWNTs) taken by a scanning electron microscopy (SEM). We have confirmed that the proposed scan algorithm detects well the parts of diameters in the wide measurement areas. We have also confirmed that the measured diameters ware close to the values estimated manually. So, we can say that the developed program is able to detect the diameters for the clearly observed CNTs. We suppose that this method is useful to evaluate the diameters of the CNTs not only for the management of the CNTs products but also for the optimization of CNTs preparation processes.