CryoEM skeleton length estimation using a decimated curve

Cryo-electron Microscopy (cryoEM) is an important biophysical technique that produces 3-dimensional (3D) images at different resolutions. De novo modeling is becoming a promising approach to derive the atomic structure of proteins from the cryoEM 3D images at medium resolutions. Distance measurement along a thin skeleton in the 3D image is an important step in de novo modeling. In spite of the need of such measurement, little has been investigated about the accuracy of the measurement in searching for an effective method. We propose a new computational geometric approach to estimate the distance along the skeleton. Our preliminary test results show that the method was able to estimate fairly well in eleven cases.