Potential of Poly-(N-Isopropylacrylamide) hydrogel as a clamper of the microrobot in gastrointestinal tract.

We successfully demonstrate that a thermally actuated reversible hydrogel, the poly N-Isopropylacrylamide (PNIPAAm), based clampers holds the intestines of a pig during the inchworm motion of microrobot. Although there are no direct relationship between hydro affinity and friction force, we found the significant friction force difference according to the surface condition change of PNIPAAm hydrogel. On the small intestine of a pig, a clamping mechanism was realized based on simple switching hydrophobic/hydrophilic surface conditions of PNIPAAm due to heating/cooling.

Reslicing axially sampled 3D shapes using elliptic Fourier descriptors.

We propose a new method that interpolates between parallel slices from a 3D shape for the purposes of reslicing and putting into correspondence organ shapes acquired from volumetric medical imagery. By interpolating the coefficients of elliptic Fourier descriptors for a set of parallel contours, a new set of slices can be directly generated at desired axial locations. Neither an explicit correspondence between points on adjacent contours nor a 3D interpolating surface needs to be obtained.

Model-based segmentation of medical imagery by matching distributions.

The segmentation of deformable objects from three-dimensional (3-D) images is an important and challenging problem, especially in the context of medical imagery. We present a new segmentation algorithm based on matching probability distributions of photometric variables that incorporates learned shape and appearance models for the objects of interest. The main innovation over similar approaches is that there is no need to compute a pixelwise correspondence between the model and the image.