Improving signal-to-noise ratio in ultrasound video pixel difference

Abstract

Pixel difference is a holistic change measure for ultrasound videos and other image sequences. It is based on Euclidean distance (l2 norm) which is calculated by interpreting each frame as a vector of pixels. Recently, we found that 3D/4D ultrasound data producesignificantly worse signal-to-noise ratio in Pixel Difference curves, which appears to be primarily due to the lower frame rate of 3D/4D ultrasound when compared with 2D ultrasound. We also found that the signal-to-noise ratio is improved when we limit the analysis to tongue-internal pixels. In this study, we seek to quantify the timing behavior of tongue gestures obtained from whole-image and tongue-internalPD. If the timing behavior is similar in both cases, we can increase the signal to noise ratio of 3D/4D ultrasound at the same time as we increase its frame rate, because imaging to a shallower depth requires less time per frame. We also examine the signal-to-noise behavior of PD curves calculated with other norms (e.g., l1, and l3 norms).