Improved spike noise removal in the scanning laser microscopic image of diamond abrasive grain using wavelet transforms

The method of spike noise removal in the scanning laser microscopic (SLM) image of diamond abrasive grain using wavelet transforms, on which we previously reported [Opt. Commun. 211 (2002) 73], is improved to eliminate spike noise with a small, fixed number of iterations of smoothing. To achieve this improvement, a new way of averaging was attempted; in addition, an accurate method to determine spike noise points in a SLM image was used. The spike noise points are smoothed only to avoid a loss of sharp edges in the image. The smoothing technique, which is applied to images that are largely corrupted by clustered spike noise, successfully removes the noise while preserving the sharp edge, with a total of two iterations of averaging for every image.