Laser Scan to Print
Many of you have been asking for a laser scanner that can turn your CupCake CNC into a 3D copier. Thingiverse user tc_fea (aka my dad) is hard at work making that a reality. Using Visual Basic, ANSYS and a lot of math, tc_fea has gone from scan to print. Leave a comment if you’d like to see the source code and we’ll be sure to post it online.
- Laser-line level
- Web camera
- Windows PC with Visual Basic
Step 1 – Scan the Object
First, tc_fea puts the scan object in front of a known, calibrated background – in this case an antique chessboard. He manually moves the laser line level incrementally across the image, taking a picture after each move.
Step 2 – Compute the Point Cloud
Tc_fea feeds the multiple scan images into his Visual Basic software for processing. The software does the following:
- Subtracts each scan image from a baseline image (with no laser line). This produces a very high contrast scan line.
- Subtracts the RGB component colors separately from the scan line, pixel-by-pixel (using Bresenham’s Algorithm). This allows a color scan.
- Applies a threshold filter to isolate the scan line from the background.
- Assemble the scan lines into a point cloud by performing a number of image transformation routines based on OpenCV methods
- Renders an image of the 3D point cloud in color
Step 3 – Mesh and Create an STL file in ANSYS
Next, tc_fea meshes his point cloud in ANSYS, a analysis package used, among other things, to analyze fighter jets and certify nuclear reactors. Overkill? Absolutely. Expensive? You bet. Fortunately, tc_fea is using an affordable demo version called ANSYS ED, which has many of the features in the full version, but limits the number of nodes and elements. Tc_fea’s program kicks out a pretty good point cloud, so you could probably accomplish the same thing in MeshLab or Blender (both free).
Step 4 – Print!
Finally, tc_fea prints the scanned part using his CupCake CNC running ReplicatorG! Homemade scan to print for less than $100!
For more things designed by tc_fea, go to http://www.thingiverse.com/tc_fea/things
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