Modified Hybrid Median Filter for Effective Speckle Reduction in Ultrasound Images

Speckle is a granular noise that inherently exists in and degrades the quality of ultrasound images. It generally tends to reduce the resolution and contrast, thereby, to degrade the diagnostic accuracy of this modality. Speckle reduction is one of the most important processes to enhance the quality of ultrasound images. This paper proposes a statistical filter, which is a modified version of Hybrid Median Filter for speckle reduction, which computes the median of the diagonal elements and maximum of the horizontal and vertical elements in a moving window and finally the two values are compared with the central pixel and the median value of the three values will be the new pixel value. The filter is tested on phantom Ultrasound image. Effectiveness of the proposed filter is compared on the basis of Peak Signal to Noise Ratio(PSNR),Root Mean Square Error(RMSE) ,Structure Similarity Index(SSI), Image Quality Index(QI) and Edge Preservation Factor(EPF) .The experimental results demonstrate that the proposed filter can reduce the speckle noise effectively without blurring the edges. Keywords— granular noise, ultrasound image, speckle reduction, hybrid median filter, statistical filter.