Performance evaluation of linear and nonlinear filters for despeckling B mode foetal heart ultrasound images

ABSTRACTEarly detection of congenital heart disease (CHD), one of the most commonly occurring congenital defects, is important to reduce mortality rates. The major drawback of ultrasound imaging is the inherent speckle noise, making visual examination of anatomical structures a challenging task. This study discusses the effect of denoising using different linear and nonlinear filters on B mode foetal cardiac ultrasound images. The exhaustive study of the performance of linear filters such as mean, Laplacian, and Wiener, and nonlinear filters such as median, anisotropic diffusion, non-local means, and bilateral filters has been carried out. Performance of the filtering technique is evaluated using various fidelity measures and a new assessment parameter edge preserving index (EPI) is also used for evaluation. Non-local means filter outperforms other filtering techniques with average fidelity values as follows: PSNR: 67.97 dB, MSE: 0.01283, RMSE: 0.109, average difference (AD): 0.005, normalized absolute error (NAE): 2 × 10−4, mean absolute error (MAE): 0.011, EPI: 0.999. This work serves as a reference on pre-processing techniques that can be applied to foetal cardiac ultrasound images for beginners.KEYWORDS: Speckle noiseultrasoundnon-local means filterfetal cardiac images4 chamber viewB mode images‌RMSEPSNREPI AcknowledgmentsWe would like to acknowledge Mediscan Systems, Chennai, India, for providing datasets to carry out this research study.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationNotes on contributorsN. SriraamSriraam N received his M.Tech degree in Biomedical Engineering and Ph.D. degree in information technology in the area of biomedical signal processing from the Malaysian University. He is currently working as Professor, Department of Medical Electronics Engineering, M.S Ramaiah Institute of Technology (RIT), Bangalore, India. He is also serving as Head, R&D at MSRIT. Dr. Sriraam is the author or coauthor of 200 plus articles published in journals and conferences. Currently, he is involved in1.5 crores worth sponsored research funded projects. His current research interests include biomedical signal processing, cognitive neuroscience, data mining, and neural networks. He is also serving as editor-in-chief of: International Journal of Biomedical and Clinical Engineering (IJBCE). Dr. Sriraam is Senior Member of IEEE and IEEE Engineering.V. Punya PrabhaPunya Prabha V is presently working as an Assistant Professor in Electronics & Communication dept. at Ramaiah Institute of Technology, Bangalore, Karnataka having around 20 years of teaching experience in various technical educational institutions. She has pursued Doctor of Philosophy in the field of Biomedical Image Processing. She has published around 15 plus papers in various National and International conferences and Journals. Areas of Interest in include biomedical engineering, IOT, Embedded system design, circuits and control engineering.T. V. SushmaSushma TV is an Assistant Professor in Electronics & Communication dept., at CMR Institute of Technology, Bangalore, Karnataka. She has worked as a research assistant in Indian Institute of Science, Bangalore, for 2 years and years teaching experience in S.J.C. Institute of Technology, Chickballapur. Sushma has received travel grant from Dept. of Science and Technology (DST), for presenting paper at AIAA conference in Nashville, USA. She has published papers in national and international journals and conferences. Her research interests include image processing, machine learning, and deep learning applications.S. SureshSuresh S is serving as the Director, Mediscan Systems, Chennai, India. A pioneer in the field of diagnostic ultrasound established fetal medicine as a specialty in India with extensive knowledge and skills in all aspects of this specialty. He established the Mediscan Systems and built the laboratory infrastructure needed for support and diagnosis in fetal medicine. From the beginning, he continues to provide a huge volume of free service to those who cannot afford care stemming from a strong sense of social responsibility. He has been in the forefront of private public partnership interacting with the government of Tamil Nadu in organizing and implementing screening programs both antenatal and neonatal screening besides training programs for doctors.