AD-96TOF1-EBZ prototyping queries

Hello! I am playing with AD-96TOF1-EBZ. My goal is to prototype a device for depth sensing obtained by scanning the VCSEL beam with my scanning device. I have several questions:

  • I am using DragonBoard410c. The ToF camera FPS behaves quite weird. It changes from 3 to 14, causing lagging. How it could be improved?
  • I would like to collimate the VCSEL illumination and direct the collimated beam to my scanning device. Is it possible to remove the diffuser without any damage of VCSEL array to place collimating optics instead?
  • Is it possible to have an output electrical signal with FPS frequency to trigger my scanning device?
  • Let’s say, we have two different objects with different reflectivity: high and low. So the light intensity, which we receive from them is different. The distance is defined by the ratio between two voltages, which represent the charge accumulation during S0 and S1 exposure. Since we have this normalization, it doesn’t matter how large the intensity is, the normalization gives us correct results for the distance. Is this correct?
  • Is it possible to adjust the CCD gain or integration time (i.e. number of laser pulses) automatically, depending on the light level (by reprogramming)? How the signal saturation can be copied with?
  • It is written in the manual, that the maximum FPS is 30. Is it possible to increase (for example, by changing the number of laser pulses or changing the number of sets, which currently is 12)?
  • I realized, that near mode uses 2 VCSELs, while medium and far use 4. Also, it seems that far mode utilizes more laser power. What are the other technical differences for the modes (both for illumination and receiving part)?

I hope, I don't annoy asking a lot of questions. Thanks in advance!

Anton.

  • 0
    •  Analog Employees 
    on Nov 20, 2020 6:01 AM 2 months ago

    Please see replies below, in the order the questions were asked:

    - Are you seeing this FPS variation when running the application on the DragonBoard410c or on a PC using the USB connection?

    - The diffuser is integrated with the VCSEL package, it might be quite risky to try to remove it.

    - The ADDI9036 generates on one of the GPOs a signal with the FPS frequency. Which revision of the board do you have, B or C? On RevB this signal is exposed on a test pad but on rev C it isn't so we need to see how to connect to it.

    - Yes, that is correct.

    - That is possible. Some information on how to do that is not public so an NDA is required.

    - The system can run up to 60fps at reduced resolution but this is not a mode that's currently being supported on the AD-96TOF1-EBZ

    - The receiver part for all the modes is the same, the difference is given by the transmitter configuration - number or VCSELs being used and the number of laser pulses for each mode, which increases from near to far. Far mode also has wider laser pulses, 33ns compared to 22ns for near and medium, to get more optical power.

      

  • Thank you very much for the detailed answer! Here are my replies (following the original numbering of the questions and your answers.)

    1) I tried to use a computer (Windows 10) through a USB connection. However, launching the Aditof Demo I got the error: "Failed to read firmware from EEPROM". And I do see the ToF camera in the device manager, it seems to work properly. What could be the reason?

    3) Mine is Rev C. What would be your advice about how to connect?

  • 0
    •  Analog Employees 
    on Nov 27, 2020 8:39 AM 1 month ago in reply to AntonB

    Which version of the aditof-demo application are you using? For version 1.6.0 the SD card image also needs to be updated. The latest image can be found here: http://swdownloads.analog.com/cse/aditof/dragonboard410c-latest-image.tar.xz

    The other option is to connect the DragonBoard410c to a HDMI monitor and run the aditof-demo applocation locally. The guide on how to do that is here: https://wiki.analog.com/resources/eval/user-guides/ad-96tof1-ebz/ug_db410c