Laser cutting

AR Marker

AR marker also known as fiducial marker provides a fixed point of reference of position or scale in a scene. AR markers can help to generate an interface between the physical world and the augmented reality content such as 3D models or videos. The camera of the device will calculate the position and orientation through AR markers in real time which is known as tracking.

A good and effective AR marker should contain the high-contrast and random pattern. I have two ideas in mind to make AR markers, one is using LED screen to make dynamic QR code and the other one is laser cutting the markers on a piece of fabric to cover the whole headset.

  • LED screen markers
    • benefits: Aesthetic pleasing, the whole screen can be hidden under light-diffusing materials such as fabric or plastic. Ideally, it can generate dynamic QR code to trigger different objects in AR.
    • shortcomings: It will take a lot of pins on a microcontroller to be able to generate animations. My original plan was using one particle photon board which has a very limit pin ports.
  • Laser cutting markers
    • benefits: Also can be aesthetically pleasing after designing nicely. Multiple patterns can be placed at different angles and trigger different objects in AR as well. No technical limitations.
    • shortcomings: Comparing to LED, It’s hard to reveal the markers.

For my prototype one, I decided to experiment with laser cutting AR markers to see if it can work nicely with Vuforia in Unity3D. I found an AR marker generator which can help to generate the high-quality complex pattern online and download as .png or .jpg which can be readable in any AR application. I converted the pattern to vector file in Illustrator and tested with the laser cutter. However, it didn’t work well as it has too many details and the headset itself isn’t big enough to be able to cover it, so at the end the laser couldn’t be able to cut in such a small piece.

I then decide to design the pattern myself to make it work better with the small surface. I created three different patterns for three angles: font, left and right.

This time it worked much better in laser cutting, I’ve also optimized my machine setting to reduce the less burnt on the fabric I was using.

IMG_3617
Machine settings: Speed, 60. Power, 10. 1.5mm felt
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Results after covering my headset

Then I uploaded my customized markers in Vuforia development site, it then generated the unity editor package for me to able to import in Unity later on. However, I was stuck here for a while because the unity can’t read my markers for some reason. It’s important to be aware that the customized image target needs to be checked as “Activate” in the Vuforia configuration in Unity.

Screen Shot 2018-06-05 at 12.33.01.png

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All the components are working properly

Here is the video of the laser cutting markers working in different angles and trigger different objects in Unity.

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