Suppression of Gradient Across Seam Line Using a Smoothing Filter in Spatially Compounded Ultrasonic Diagnostic Images

A method to reduce seam line artifact in spatial compounding of ultrasonic images is presented. Spatial compounding is a speckle reducing imaging technique in which a number of ultrasound images of a given target that have been obtained from multiple view angles are combined into a single compounded image by combining the data received from each data point in the compounded image. Since different view angle results in different view area, and the images of different view areas are combined into an image, the compounded image consists of regions with different signal to noise ratio, and the boundary lines between these regions are visible in the compounded images. In this paper, we present an algorithm that effectively reduces the visibility of this seam line in the spatially compounded images. Design procedure for a smoothing filter is described and the results of applying the filter to in-vivo ultrasonic images are analyzed.