Mixed filter for noise suppression in an ultrasonic image

A mixed filter for noise suppression in the ultrasonic image is proposed. In the method, noise detection is operated in the ultrasonic image, and then the image is processed by the rank-ordered adaptive median filter on condition that the detected pixels contain salt and pepper noise, and then the logarithmic transformation of the image is operated, and then the transformed image is processed by the mean filter with fuzzy authorized values, and then the final image is obtained by the exponential transformation of the reprocessed image. A full description of the principle of the proposed method is given. The experimental results show that the proposed method is effective on noise suppression and edge preservation to the ultrasonic image from a small underwater target.