There are 5 error codes that may be displayed if calibration fails.
The error codes description is as below:
Calibration error code 1 : This means that all the dots were not detected. This could be because the lighting is poor or the position of the scanner is not right (the board isn't within the bounding box).
Calibration error code 2: This one is a bit more tricky. This is basically giving is threshold values of NaN. This means that the scan is so off that you will need to do it again until it doesn't occur.
Calibration error code 3,4 and 5 are much like error code 2 with large errors in the set-up of the calibration space. The descriptions of these are much more vague as the errors are illustrating that there is something very fundamentally wrong with the setup.
Let's get technical....
The calibration process goes through several stages of calculations. The stages 3,4 and 5 are performed based on the data gathered in stages 1 and 2. The error codes 3,4 and 5 are picked up later as every phone is different and we have fairly loose tolerances in the early stage(1 and 2). These tolerances become smaller as the calibration step progresses to the later stages. These tolerances are thresholds for the non-linear fit that we are applying on the calibration scan.
Hence an error code in stage 3-5 is only meaningful to us(internally) because we can go through the log files to pinpoint the major reasons for the failed calibration. This is also the reason that there is a fundamental issue with the set up for calibration. The codes 3-5 were put in so that we could better diagnose things and keep track of where the problem is occurring and improve the algorithms.
You can refer to our calibration walk-through video which shows the setup that is best for successful calibration
Calibration is indeed a virtue