Setting up the Right Kind of Lighting to Bring AR Into Your Lab

Lighting tips and tricks for best results using inspectAR

Using inspectAR
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4
 Min read
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January 20, 2021

Lighting and Augmented Reality

inspectAR brings the full weight of your smartphone or laptops modern compute system to bear on your circuit board in the lab. Using your device's camera we can superimpose any net, component or layer onto your board in real time. It’s a serious time saver for both hobbyists and professionals alike and this is the only tool on the market using augmented reality to improve electronics lab work.

But How Does it Work

In order to make your board work with the inspectAR tool you will need to go through a brief calibration process where you take a picture of both sides and confirm where the board’s edges are. These images are used in an advanced computer vision algorithm when you launch the board in AR mode. You get a very high level state-of-health check from inspectAR whenever you are in the AR scene, the tracking indicator will tell you whether the computer vision algorithm has found the top or bottom side of your board. The more similar your environment is to when you calibrated the board the easier it will be for the computer vision algorithm to match the original calibration image you took.


What Does Bad Tracking Look Like?

When your board is not tracking you will unable to add or select any overlays and the tracking indicator will say 'Searching' like it does in the photo below.

PCB debugging is easy with inspectAR
A PCB that has lost tracking

Alternatively, you might notice that you can get tracking, but then quickly lose it as soon as you touch the board. Generally speaking you should be able to cover 50%-60% of the board and still maintain tracking.

How to Diagnose Bad Tracking

Have You Been Doing Any Assembly Work to the Board?

Soldering and de-soldering components will change the board’s appearance from when you originally took the calibration image. We recommend re-calibrating once about 20-30% of the board's surface area has been assembled. If you aren’t able to zoom in low enough to keep the overlays tracking while your soldering iron or tweezers are in view try using our AR Stabilization Mode or Freeze Mode to make the overlays more stable. 


Assembly with inspectAR
Populating Components Will Change the Board From its Calibration Image


Are Tall Components Casting Shadows?

If there are no shadows on your board when you calibrate, but then a tall component begins to cast shadows then you will most likely need to re-calibrate to that situation once the shadows begin to change 20-30% of your board. If this starts to get too problematic you’ll need to invest in some better lighting for your lab station.

Shadows are caused by directional light, if light was shining on your board from every angle then it would be impossible for there to be shadows. In practice we can’t all live inside a room with mirrors for walls, so a good compromise to diffuse light sources in the room or use a ring light on a very low power setting (too much will cause glare).


Directional Lighting casts shadows on PCBs
Highly Directional Lighting is Causing These Header Sockets to Cast Long Shadows


Is Glare Being Cast on the Board?

Glare is caused when your light source has too much power and the surface of your board is reflective. Sparsely populated boards, milled PCBs showing bare copper, boards with large screens, and unpainted aluminum heat sinks are all prone to glare problems.

To mitigate glare on the board you will need to decrease the intensity of the light in the room you are working in. A dimmer switch will be your best friend here. If the lights you are working with are not dimmable you can try diffusing them similar to the shadows step, or even turning the lights to point at a wall or the ceiling so they do not shine directly on the board.

Glare on a PCB can hamper inspectAR
Bright Glare Needs to be Diffused for Tracking to Work

Have You Shared the Calibration to a Device with a Different Camera?

In general, you can share calibrations between devices with different cameras without a hitch. However, sometimes the calibration will not be as robust to glare, shadow, and assembly problems. In more rare cases, the intrinsic differences between the two calibrations can differ so much that the calibration will not work at all. 


If this is the case you can fix the problem by re-calibrating on your new device. However, you’ll need either a supported smartphone or desktop with an appropriate webcam. We recommend a 4k USB3 web cam, however 1080p is the minimum resolution you can use to make a calibration. Between 4k and 1080p resolutions, you’ll notice that you have less zoom available once you enter AR mode. At a 720p resolution you won’t even be able to make calibrations, however you can still use a shared calibration from a different supported device.

Recap:

If you notice some problems with the stability and tracking of your AR overlays remember that differences between the environment the board was calibrated in, and the environment the board is currently in can affect the quality of your AR experience. To improve tracking:

  • Re-calibrate after 20-30% of the boards surface area has changed during tracking.
  • Add diffuse, low power light to get rid of glare and shadows.
  • Check if the calibration was shared from another device, if so re-calibrate.


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