Experimental ultrasonic probe positioning method using optical triangulation

In ultrasonic imaging, including echocardiography, the location of the section view is defined manually. In case of research and development of speckle tracking methods using left ventricle phantoms the repeatability of probe positioning is crucial for acquired data interpretation. In this work an optical system and method for probe positioning are proposed. This systems consists of a set of two cameras, a calibration frame with 8 markers of with known coordinates and a probe holder with 4 markers. The described calibration process involves image segmentation and extraction of the camera projection matrices. The positioning method uses the same initial image processing steps followed by estimation of markers’ positions using the triangulation method. Performance of the system is tested using a validation plate with five coplanar markers. Obtained precision of positioning estimated based on the reprojection errors at each step of the process and as validation distance errors reaches approx. 2 mm, which is considered sufficient in case of ultrasonic imaging based on its resolution.