The study on reduction for near field clutter (NFC) artifact based on wavelet thresholding method in ultrasound image using Field II program

The near field clutter (NFC) artifact causes affect diagnosis of the ventricular apical region when echocardiography that basic examination for a heart in apical view. Therefore, the purpose of this study was to quantitatively evaluate the usefulness of the designed de-cluttering algorithm based on wavelet thresholding method for removing NFC artifact in acquired ultrasound image. To acquire NFC artifact image, we used field II program based MATLAB software. Also, we designed algorithm that discrete wavelet transform (DWT) and inverse wavelet transform (IDWT) algorithms with soft threshold method. For that purpose, root-mean square error (RMSE), peak-signal to noise ratio (PSNR), the Pearson correlation coefficient (CC) and universal quality index (UQI) were used for quantitative analysis of the NFC artifact image and restored image. According to the results, restored image in the added only NFC artifact showed improvement of the image characteristics by RMSE and PSNR about 5.0 and 2.24 times than NFC artifact image, respectively. Also, CC and UQI characteristics of the restored image improved about 1.25 and 4.47 times, compared to NFC artifact image, respectively. And restored image in the added many artifacts showed improvement of the image characteristics by RMSE and PSNR about 8.33 and 2.08 times, more than NFC artifact image, respectively. Also, CC and UQI characteristics of the restored image improved about 5.64 and 6.25 times, compared to NFC artifact image. In conclusion, our results demonstrated that we can improve image characteristics by using our proposed NFC artifact reduction algorithm based on wavelet thresholding method.