A Novel Technique for the Restoration of AFM Images EnablinganEstimated Impulse Response forthe AFM to be Calculated Using Square Pillar and Cylindrical Pillar Samples

摘要

All atomic force microscope (AFM) images suffer from distortions, which are principally produced by the interaction between the measured sample and the AFM tip. The atomic force microscope (AFM) is a very important instrument for use in nanotechnology and biology since it can be used to measure a wide variety of objects, such as nano-particles and cells, either in air or liquid. However, the images that are measured using AFM are distorted because of both the influence of the tip geometry and the dynamic response of the instrument. This influence means that the images do not accurately represent the real shape of the measured particles or cells. Therefore, it is necessary to reconstruct the AFM tip shape. This paper proposes a new approach (impulse response technique) to reconstruct the AFM tip shape from either a square or cylindrical pillar sample that is measured using AFM. Once the tip shape is known, a deconvolution process is carried out between the estimated tip shape and typical AFM 'distorted' images in order to reduce the distortion effects. The experimental results and the computer simulations validate the performance of the proposed approach, in which it is shownthat the AFM image accuracy has been significantly improved. The suitability of this novel approach for restoring AFM images has been confirmed using both computer simulation and also with real experimental AFM images. The blind tip estimation approach is anindustrial and research standard algorithm for the restoration of AFM images. We therefore also compare the proposed algorithms with the blind tip estimation algorithm, via the use of both computer simulations and real AFM images, and our algorithm is shown to give enhanced results when compared with the blind tip estimation approach.