Abstract:
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Photogrammetry is a technique which allows to determine the geometrical properties of objects or scenes
from bi-dimensional images. Said technique is based on the use of complex algorythms which are able to
detect similarities among different images that represent views of a single point in the space.
This project aims to be an example of application of protogrammetry techniques through open-source
software, in order to make it accessible to anyone who wants to reproduce what is shown here. In order to
do this, the minimum resources have been utilized to invent, design and build a machine which is capable to
take a series of photographies in a stable, automatic fashion. Said machine is controlled by a Raspberry Pi
mini-computer, equipped with a distribution of the GNU operating system with the Linux kernel, which
executes orders expressed in scripts in the Python language. These scripts are in charge to send the
approppriate signals that make a small stepper motor installed on the machine structure to make a web
camera to orbit around a small object.
Once the images are taken, they are extracted and introduced into a computer with enough processing
power to perform the object’s 3D reconstruction tasks. Once this is finished a refined and optimized mesh is
obtained, which contains the reconstructed geometry of the object. Then repairing and texturing tasks are
carried through. Following to this, manual modifications are applied in order to obtain a mesh whose surface
is free of holes, and the result of this is ready to be 3D printed by using any of the printing techniques
currently available.
This project exposes the issues that have been addressed when thinking up this device, as well as the
implemented solutions to accomplish a working prototype and its components, both as commercial solutions
as well as regarding the design and manufacturing of the specific components. The designed parts have been
3D printed in polyamide by placing a manufacturing order, although the use of this technique and material
has been chosen based on previous experience and it is not mandatory for this project. This being so, it can
be accomplished by choosing materials which provide the same or higher mechanical features, the same way
that it is possible to modify the geometry of said parts in order to make their manufacturing easier, as long
as said modification does not affect their working principle. |