• State Resolved
  • Locked Locked
  • Replies 10 replies
  • Answers 3 answers
  • Subscribers 30 subscribers
  • Views 922 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

OPT8241: cdk-evm

OPT8241: cdk-evm

Deep Aum
Prodigy 110 points
Part Number: OPT8241
Other Parts Discussed in Thread: OPT9221

Hi,

I have gone through the document of EVM and having two queries as below. Please give me right advise or suggestions or correct me if in wrong way.

1. For OPT8241 EVM, there is mentioned Field of View: 74.4 (H) X 59.3 (V). Does it in cm? what is the unit of this value? Concern: My object size it 350 mm X 350 mm so does the lens used in EVM can work for me?

2. It has mainly two part: i. Sensor board and ii. Illumination board. Sensor board has ToF sensor, right? should I need to interface camera with this system to have better result or does it work perfectly? If required then how to make in sync to camera module with ToF sensor board?

We are going to purchase this board for PoC. Our application to measure alignment of object (using non-contact 3D method and depth measurement) which is not moving. Please share your suggestions/feedback for us.

Thanks in advance for your support.

Regards

Deep

  • 0
    TI__Expert 3975 points
    Hi Deep,

    Here are the answers to your queries:

    1) The FoV is in degrees. The lens will be able to support 350 x 350 sq mm

    2) Do you mean, if another RGB camera is needed for better results? I'm sorry, I don't understand the context.
    Please explain the second question in more detail .

    For a PoC, you should be able to directly use OPT8241-CDK-EVM. You can check the accuracy and power requirements using the 3DToF System Estimator tool:
    www.ti.com/.../sbac124

    Suramya
  • 0 in reply to Suramya Gupta
    Prodigy 110 points

    Hi  

    Thank you for your quick response.

    For batter clarity, Please see below details and updated specs.

    I need to measure object alignment from front side (non-contact) way, Object size may be 750mm X 750 mm (updated/changed). I can place OPT8241 EVM with distance of 850 mm to 1 meter max., my query related to this EVM kit is

    1. What is the resolution I can get with this sensor (OPT8241, 320X240array) and lens used in this kit? (Resolution in terms of distance between two pixels of entire image of this object.)

    2. Does this lens work and provide required FoV. (I have gone through the suggested tool and see that we can change FoV but my quest is for this kit.) thanks

    Regarding your question: I have seen few videos where ToF used with stereo cameras also so as per my requirement explained above, should i need to add camera externally or ToF sensor can do the job?

    again thanks you very much for your support.

    Regards

    Deep

  • 0 in reply to Deep Aum
    Prodigy 110 points
    Hi

    Need to clarification regarding FoV of lens in OPT8241 EVM. it shows 59.3 (V) degree means if object will place front side of lens with distance of 850mm than as per simple maths (Trigonometry) Tan(29), I can cover approx 900 mm vertical, right? please guide me if something wrong.
    What about the resolution of that image? means if i wish to measure distance between two pixels of that image then how much accuracy i can get, any equation for that?

    Also request you to look at 2nd point of my previous query and advice me.
    I need to finalize this OPT8241 EVM in two days so highly appreciate your quick response.

    Thanks
    Deep
  • 0 in reply to Deep Aum
    TI__Expert 3975 points

    Deep, 

    Yeah, you're correct. It can be calculated using simple geometry. Resolution is 320x240. 

    Focal length of the lens in the EVM is aroud 3 mm (it varies around ~10% from lens to lens) and pixel pitch is 15 um. So, at a distance of 1m, a pixel would cover around 5 mm length of the object. 

    Yes, OPT8241-CK-EVM has an FOV of 74.4 (H) X 59.3 (V). I was mistaken, thinking that you wanted to design your own module - that's why I suggested the tool. This FoV will not change for the EVM. 

    Hope this helps.

    Suramya

  • 0 in reply to Suramya Gupta
    Prodigy 110 points
    Thank you very much for your prompt response. Really It helps lot to move step forward.

    Last one query: :)
    As you know my application, What will be depth measurement resolution I have If using OPT8241 EVM kit?

    I have seen in 3D tool suggested by you that It can be upto 0.1mm!! so How much with specs of this kit and my application? Does it work for PoC? So we will develop customize one after that to meet required specs.

    Thanks & Regards
    Deep
  • 0 in reply to Deep Aum
    TI__Expert 3975 points
    Deep,

    The estimator tool is an approximation and it is very difficult to achieve such a depth resolution. As you can see from the tool, the power requirements will be very high.

    The default settings that you see in the tool (resolution of 14 mm at 1 m) is approximately correct for the EVM. For PoC, you should use this value - this can be improved using a custom system design.

    Please see www.ti.com/.../sbau219d.pdf for more info on how to define the specifications - refer section 11.1

    Suramya
  • 0 in reply to Suramya Gupta
    Prodigy 110 points

    Hi Suramya Gupta (4757684)

    Thanks for your clarification and sharing reference doc, I will go through it.

    For quick discussion, Actually I need to have at least 1mm accuracy measure in Depth, For PoC 2 mm will be fine.

    Please check below screen shot I have applied combination, Request your advise on this.

    Please note that I have selected Depth resolution: 2mm, Binning: 10 and change FoV

    Thanks & Regards

    Deep

  • 0 in reply to Deep Aum
    TI__Expert 3975 points
    Hi,

    You cannot change the FoV of the lens present in the EVM. You need to enter the diagonal FoV. Please go through the document.
    Please go through the OPT9221 and OPT8241 datasheets for further details about the parameters.

    Suramya
  • 0 in reply to Suramya Gupta
    Prodigy 110 points
    Hi

    I have choose FoV as per EVM (instead of 59.xx, used 60 for vertical side).
    please guide if I follow wrong way.

    Thanks
    Deep
  • 0 in reply to Deep Aum
    TI__Expert 3975 points
    As I said previously, you have to use the diagonal FoV. Please use the default values if you want to check performance of OPT8241-CDK-EVM.

    Suramya