Sentis-ToF-M100 Offset Calibration

From BlueWiki

Jump to: navigation, search

Sentis-ToF-M100 Offset Calibration

The Sentis-ToF-M100 currently supports seven different modulation frequencies which calibration data can be stored for. Among others the camera can calibrate its distance offset. These compensation values are stored in the register map from address 0x00C1 on. In order to activate compensation, set Bit 13 in Register ImgProcConfig (0x01E0). Offset compensation values can be set manually or automatically. Every modulation frequency must be treated seperately.

Preparation for offset calibration

  1. Place your Sentis coplanar in front of a uniform white target
  2. Info: the measuring is done on a 4x4 pixel window in the center of the field of view
  3. Avoid extreme environmental light conditions or avoid light completely
  4. Plug the Sentis' power cable and control interface connection
  5. Adjust the integration time in register 0x0005 in order to have an amplitude in the center of the image of approximately 1000-3000
  6. Measure the distance between the sensor surface and the uniform white target and write it in [mm] into register RealWorldXcoordinate (0x0020)
  7. Set the desired modulation frequency at which the Sentis should be calibrated; possible values to write into register ModulationFrequency (0x0009):
    • 0x0 or 0x01F4 ... 5MHz
    • 0x1 or 0x02EE ... 7.5MHz
    • 0x2 or 0x03E8 ... 10MHz
    • 0x3 or 0x05DC ... 15MHz
    • 0x4 or 0x07D0 ... 20MHz
    • 0x5 or 0x09C4 ... 25MHz
    • 0x6 or 0x0BB8 ... 30MHz
  8. Wait for all the above changes to take effect: two frame times (1 / frame rate)
  9. Wait for temperature to level off if the modulation frequency was changed

For automated calibration offset calculation proceed with:

  1. Place the calibration command in register: write 0x0013 into register 0x000F
  2. Poll register CalibrationExtended (0x0021)
  3. When finished, the CalibrationExtended register should read 0x00A1
  4. For any other status/error code in CalibrationExtended, please refer to the software user manual
  5. In order to repeat offset calibration for a different modulation frequency, restart at step 7

For manual offset adjustment proceed with

  1. Check the measured distance in the center of the image. We suggest to average the distance over some frames.
  2. Compare the measured distance with the real one and calculate the difference (offset = real distance - measured distance).
  3. Write the offset as signed integer into one of these registers, depending on the modulation frequency it is meant to be for:
    • 5Mhz ... 0x00C1
    • 7.5Mhz ... 0x00C2
    • 10Mhz ... 0x00C3
    • 15Mhz ... 0x00C4
    • 20Mhz ... 0x00C5
    • 25Mhz ... 0x00C6
    • 30Mhz ... 0x00C7
  4. Check how the distance in the data interface changes
  5. In order to repeat offset calibration for a different modulation frequency, restart at step 7

In order to preserve the offset calibration beyond a device reset, the whole register map must be saved to flash:

  1. Write 0x4877 into register 0x0022
  2. Wait at least for two frame times (1 / frame rate)
  3. Write 0xdd9e into register 0x0033
  4. After a short time the operation is finished and the result is stored in register 0x0034; in case of a success it reads 0x0001 (otherwise, please refer to the software user manual)
Personal tools