Methods, systems and computer program products are provided for determining
an obscured contact point based on a visible portion of an acoustic sensor
of a medical device contacting a patient by acquiring a first image
containing an upper surface of the acoustic sensor from a first viewpoint
and a second image containing the upper surface of the acoustic sensor
from a second viewpoint different from the first viewpoint. The acoustic
sensor is located in the first image and the second image and the centroid
of the acoustic sensor is determined based on the location of the acoustic
sensor in the first image and the corresponding location of the acoustic
sensor in the second image. A plane of the visible portion of the acoustic
sensor is also determined based on the position of the upper surface of
the acoustic sensor in the first image and the corresponding position of
the upper surface of the acoustic sensor in the second image. The contact
point of the obscured portion of the acoustic sensor may then be
determined by projecting a predetermined depth through the centroid of the
acoustic sensor in a direction having a predefined relationship with the
plane of the visible portion of the acoustic sensor.