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OPT8241-CDK-EVM: Questions about TI'S TOF and OPT8241-CDK-EVM

youxin Zhang
Prodigy 30 points

Part Number: OPT8241-CDK-EVM

Hi!
Our application focus on the household robot/sweeper.
Our ranging aim is to achieve mapping(slam)，make the robot walking autonomously.
Now we are using Trianulation Ranging Principle in our projects.
In our understanding ,TOF should be prior to triangulation ranging in precision.So we hope to see TI's TOF scheme.
Currently,what we focus on are below----
1.In door application:
The maximum ranging is between 2m~5m
2.Error precision:
In our opinion,ToF's precision not rely on the ranging distance,and it should be in the millimeter range. Right?
3.Ranging angle:
At present,we think the ranging object of  TI's TOF is a "320x240"plane,if our understanding right, we want  to know the angle of ranging.
In common,  for ToF method, in case the object being a point ,there will be no angle problem and the most care should be about the refresh rate.
But in case of the object being a plane, we would need the ranging angle, and we think the horizontal ranging angle should be over 60 degree. 
4.Refresh rate:
As mentioned in item '3', TI's TOF scheme should be a plane ranging,so there is no more requirement on the refresh rate.
But if it is kind of a point ranging,the refresh rate should be over 1000 per second.
5.
Laser Safety:According to USA FDA on laser's certification, would your product can acheive CLASS 1 for  laser safety.
Laser wavelength.
Laser optical power.
6.Optical lens:
As the reception object is a plane,what kind of lens should be chosen to use with it?
Thank you and looking for your reply~
  • 0
    TI__Expert 3495 points
    youxin:
    Please find answers (>>) below:
    1.In door application:
    The maximum ranging is between 2m~5m
    >> This is achievable with adequate illumination.
    2.Error precision:
    In our opinion,ToF's precision not rely on the ranging distance,and it should be in the millimeter range. Right?
    >>  TOF *precision* is less dependent on range, but more on calibration.  But TOF *accuracy* depends on amplitude of reflection.  Accuracy is typically 1% of range, so at 5m you can expect about 5cm of accuracy.
    3.Ranging angle:
    At present,we think the ranging object of  TI's TOF is a "320x240"plane,if our understanding right, we want  to know the angle of ranging.
    >> I think you're referring to field of view (FOV) angle.  Our OPT8241-CDK-EVM comes stocked with 87 deg diagonal FOV.  You can use lenses/illumination with different FOV.
    In common,  for ToF method, in case the object being a point ,there will be no angle problem and the most care should be about the refresh rate.
    But in case of the object being a plane, we would need the ranging angle, and we think the horizontal ranging angle should be over 60 degree. 
    4.Refresh rate:
    As mentioned in item '3', TI's TOF scheme should be a plane ranging,so there is no more requirement on the refresh rate.
    But if it is kind of a point ranging,the refresh rate should be over 1000 per second.
    >>  Single point TOF reference rate can be 1000's of samples per second.  320x240 array can achieve frame rate of 120 fps.
    >>  If your interest is in single-point TOF, please contact ti-3dtof@list.ti.com for further information.
    5.
    Laser Safety:According to USA FDA on laser's certification, would your product can acheive CLASS 1 for  laser safety.
    Laser wavelength.
    Laser optical power.
    >> Our product can be combined with different illumination, including laser and LED.  If laser, Class-1 can be achieved with proper selection of laser, diffuser FOV and laser power.  Our OPT8241-CDK-EVM is tested for Class-1 under IEC60825-1 2nd Ed.   Wave length is 850nm.  Optical power is ~900uW per laser w/ diffuser, (measured at 100mm distance, 7mm aperture).  New design must follow IEC60825-1 (2014) 3rd ed.   
    6.Optical lens:
    As the reception object is a plane,what kind of lens should be chosen to use with it?
    >> We recommend ARC coated F1.1 or F1.2 lenses optimized for 850nm with CRA < 20 deg.  For OPT8241 image format is 1/3" (sensor area diagonal).
    -Larry
  • 0 in reply to Larry Li
    Prodigy 30 points

    Dear Larry:

    Thanks a lot for your kindly help!

    1.

    I would like to know if I can run your demo board (OPT8241-CDK-EVM) easily.

    For example， I can connect the OPT8241-CDK-EVM to my Pc and I can measure the depth for my room without any programming?

    2.

    Do I need to buy Laser or Lens based on this board?

    Does this board include laser and lens?

    3.

    what is the data out format of chip OPT8241?

    Can I calculate the depth data based on this output by myself without the controller chip OPT9221:

    ( because the controller is too big )

    Does TI provide this algorithm ? ( source code or Library )

    4.

    Does the OPT9221 also control the illumination LED/LD?

    5.

    And where can I download the technical document to introduce the theory of this chip?

    6.

    And I will write the email to ti-3dtof@list.ti.com to ask the information of the single point

    Thank you!

  • 0 in reply to youxin Zhang
    TI__Genius 14645 points
    Hi,

    Please find answers inline (>>) below.

    1.

    I would like to know if I can run your demo board (OPT8241-CDK-EVM) easily.

    For example， I can connect the OPT8241-CDK-EVM to my Pc and I can measure the depth for my room without any programming?

    >> We provide VoxelViewer software for Windows PCS to easily evaluate the board and measure depth data.
    The EVMs are calibrated in the factory and you can use the software to select a calibrated profile ("Metrilus Long Range (HW)" is the best one).

    VoxelViewer can be downloaded from here:
    www.ti.com/.../sbac143


    2.

    Do I need to buy Laser or Lens based on this board?

    Does this board include laser and lens?

    >> This EVM includes lasers and lens. You do not need to buy these separately.

    3.

    what is the data out format of chip OPT8241?

    Can I calculate the depth data based on this output by myself without the controller chip OPT9221:

    ( because the controller is too big )

    Does TI provide this algorithm ? ( source code or Library )

    >> The OPT8241 is sold as part of a chipset and the companion controller OPT9221 is required.
    We do not support running the OPT8241 directly.


    4.

    Does the OPT9221 also control the illumination LED/LD?

    >> The illumination modulation is directly controlled by the OPT8241. The OPT9221 does not control the LED/LD directly. The LED/LD needs to be powered separately.

    5.

    And where can I download the technical document to introduce the theory of this chip?

    >> You can refer to our whitepapers on Introduction to Time-of-Flight Camera (www.ti.com/.../sloa190) and Introduction to Time-of-Flight System Design (www.ti.com/.../sbau219)


    6.

    And I will write the email to ti-3dtof@list.ti.com to ask the information of the single point

    Thank you!