🧨 The accuracy of the calculations, especially for level 2, is directly related to how well you calibrate your equipment. Please pay close attention to the following instructions.

Video guide for you in here 📹

<aside> 💡 Calibration must be performed whenever you collect data with a new device. However, you only need to do this once for each device.

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1. Print a chessboard from the application

click here to view and download the chessboard

• The larger the paper you print on the board, the better
  • A4 paper is the bare minimum, but larger is better for quality calibration

2. Measure the chessboard

• After printing, it is necessary to measure the chessboard. Specifically, the size of the two marked points, per millimeter exactly

  

3. Prepare a chessboard

• the printed chessboard needs to be perfectly flat
  • in the worst case, it can be glued to the wall or board (on all four sides) and make sure that it is taut and level (if the board is wavy, the resulting calibration will be unusable)
  • please try to take photos in daylight or in good lighting

4. Start the calibration

• Click on the "Device calibration"
  • the process redirects you to the screen, where it will be necessary to take pictures of the chessboard by 9x6 squares from different angles 11 times
• We recommend that you alternate distances when taking photos
  • the distance range depends on how large the board is printed
    • something between 0.5 m and 5 m is suitable for A4 paper

It is necessary to alternate the placement of the chessboard in the photo ( 0.5 m and 5 m)

• Make sure you take photos so that the chessboard is at least once at each point on the screen that the camera lens captures
  • upper right corner, upper left corner, middle, middle top, ...
• More photos are useless if the photos are not of good quality (not good light, not blurring photos)
  • of course, it may happen that some of the photos fail, and then it is advisable to have a few extra pics, but if there is a systematic error in their collection, the result will be poor regardless of their number

We also recommend taking photos from different angles.

• do not stand directly in front of the board, but take a picture of it, for example, slightly from below or from the side
• don't be afraid to add a few (2-3) photos there at a more extreme angle (eg: 45˚)

If the calibration does not pass, some photos need to be taken again.