  Tissue deformation in ultrasound (US) imaging leads to geometrical errors
when measuring tissues due to the pressure exerted by probes. Such deformation
has an even larger effect on 3D US volumes as the correct compounding is
limited by the inconsistent location and geometry. This work proposes a
patient-specified stiffness-based method to correct the tissue deformations in
robotic 3D US acquisitions. To obtain the patient-specified model, robotic
palpation is performed at sampling positions on the tissue. The contact force,
US images and the probe poses of the palpation procedure are recorded. The
contact force and the probe poses are used to estimate the nonlinear tissue
stiffness. The images are fed to an optical flow algorithm to compute the pixel
displacement. Then the pixel-wise tissue deformation under different forces is
characterized by a coupled quadratic regression. To correct the deformation at
unseen positions on the trajectory for building 3D volumes, an interpolation is
performed based on the stiffness values computed at the sampling positions.
With the stiffness and recorded force, the tissue displacement could be
corrected. The method was validated on two blood vessel phantoms with different
stiffness. The results demonstrate that the method can effectively correct the
force-induced deformation and finally generate 3D tissue geometries
