Some image processing applications like segmentation need effective techniques that work as edge detection and extraction, many filters in this field fail to achieve the desired result and consequently the further processing fails, so it is needed sometimes to modify a technique to work in robust and effective way. In ultrasound, although it is a common and real-time non-destructive test methods, but processing and analyzing such images require special filters and modifications to overcome some weakness sides in this field, especially when scanning objects comparable to the acoustic wavelength. In this paper, two modified filters were suggested, first one is two-step unsharp filter, in this techniques the image was enhanced twice the first time the edges that extracted from the original scaled image where added back to the image, and in the second time the same edges were added to the scaled enhanced image. The second technique is summarized as adding back the Low-High and High-Low bands that were extracted previously from the original image by Haar wavelet transform to the image which reinforce its edges.
International Letters of Chemistry, Physics and Astronomy (Volume 52)
H. S. Jamila et al., "Edge Detection in Ultrasound Images Based on Modified Unsharp and Wavelet Transform Filters", International Letters of Chemistry, Physics and Astronomy, Vol. 52, pp. 90-99, 2015