1. University of Pennsylvania Arc and line extraction Model creation Manufacturing Algorithm for model extraction We utilize a six step method for creating a solid model from either a photo or a synthesized optimal design. Image filtering Edge detection Object characterization We rely on two primary assumptions: the images of interest have high contrast the images are not cluttered with extraneous visual data Each step utilizes simple image processing techniques.

2. University of Pennsylvania 1. Image Filtering and Thresholding The synthesized designs are generally coarsely pixelated. We use a blurring operation to smooth the image A simple contrast threshold is then used to separate areas with material from ones without 2. Edge Detection We use a simple binary filter to extract edges from the image Each edge is guaranteed to be only a single pixel wide 3. Object Extraction Assume that all objects have closed loop boundaries Scan the image to find a boundary, and then follow that boundary to identify an object The connectivity of each object is stored for further processing

3. University of Pennsylvania 4. Arc and Line Extraction Each object is analyzed to generate a model based on best fit arcs and lines Algorithms inspect groups of adjacent points to see if arcs or lines can approximate points to within a given tolerance 5. Model Creation Each object is resolved into a connected set of lines and arcs and written to an IGES file The IGES file can be read by a variety of programs for FEA/FEM, solid modeling, etc. We import into Pro/Engineer and generate a 3- D model by extrusion 6. Manufacturing A macro prototype is then generated from the solid model Using a Fused Deposition Modeling (FDM) machine, a plastic prototype can be generated (it is slightly brittle) Using a CNC machining center, more robust prototypes can be machined out of polystyrene or aluminum