Method of medical ultrasonic image de-noising based on fuzzy PCNN in the wavelet domain

Based on the analysis of the speckle noise and PCNN's properties, PCNN is introduced in to wavelet domain, by combining the thought of the Soft-threshold de-noising, Soft-threshold de-noising method of medical ultrasonic image based on PCNN(ST-PCNN) is proposed. The advantage of ST-PCNN is that PCNN recognizes the coefficients of high frequency in wavelet domain are realized, and then the wavelet coefficients are processed by corresponding methods. ST-PCNN improves the disadvantage that PCNN can not accurately determine the position of speckle noise and the fixed threshold makes some high-frequency signals loss, and better reserves the wavelet coefficients of high frequency signal which are lower than the fixed threshold. On this basis, fuzzy algorithm is applied in the model of PCNN, method of medical ultrasonic image de-noising based on Fuzzy PCNN in the Wavelet Domain (F-PCNN-WD) is proposed. The proposed method make use of fuzzy algorithm to remove the wavelet coefficients of speckle noise which are greater than the ignition threshold value of PCNN, so the speckle noise can be better removed. The experimental results show that ST-PCNN and F-PCNN-WD can not only remove the noise but also reserve the detail information and the image edge.