Novel reconstruction and feature exploitation techniques for sensorless freehand 3D ultrasound

Abstract

Out-of-plane motion in freehand 3D ultrasound can be estimated using the correlation of corresponding patches, leading to sensorless freehand 3D ultrasound systems. The correlation between two images is related to their distance by calibrating the ultrasound probe: the probe is moved with an accurate stage (or with a robot in this work) and images of a phantom are collected, such that the position of each image is known. Since parts of the calibration curve with higher derivative gives lower displacement estimation error, previous work limits displacement estimation to parts with maximum derivative. In this paper, we first propose a novel method for exploiting the entire calibration curve by using a maximum likelihood estimator (MLE). We then propose for the first time using constrains inside the image to enhance the accuracy of out-of-plane motion estimation. We specifically use continuity constraint of a needle to reduce the variance of the estimated out-of-plane motion. Simulation and real tissue experimental results are presented.

Out-of-plane motion estimation based on a Rician-Inverse Gaussian model of RF ultrasound signals: speckle tracking without fully developed speckle

“…Many of the proposed correlation-based methods focus on the improvement of FDS detection by introducing different FDS detection methods, such as optimal low-order moments 6 , novel meshing 7 , and the use of the K-S test as a non-parametric goodness of fit 8 . Other efforts intend to increase the motion estimation accuracy by adapting the correlation curve and compensating the loss of coherency by using additional information such as correlation in the axial and lateral directions 8 , beam steering 9 , developing a heuristic method to consider the coherent part of the image 10 , using Maximum Likelihood Estimators (MLE) for motion estimation 11 , or incorporating the information of several noisy measurements in a probabilistic framework 12 . Recently a new learning based method of out-of-plane motion estimation on imagery of real tissue has been introduced 13 .…”