• DepthAI-v2

  • IMX462 low-light is not good at low light

Hey,

sorry, just got to test it today/tonight.

Attached, you find that we can barely see anything even though there are multiple light sources nearby. Cranking up ISO and exposure time did not help (second image). It is definitely better than an IMX477 (which is pitch-black), but considerably worse than, e.g. a Sionyx Nightwave. Having seen tutorials in the internet with the exact same IMX462 sensor makes me think there is a driver issue or the like. Potentially related to internal gain settings, not sure.

Default cam_control.py settings (I think 20ms, 800 ISO)

Cranking up exposure as high as 100ms (setting cam to 10 FPS) and max ISO 10000 (even though I think it has no effect setting exposure and ISO higher than some number)

IMX477

Sionyx Nightwave

What do you think?

Hi @BenjaminKiefer ,

even though I think it has no effect setting exposure and ISO higher than some number

You are correct, after 33ms exposure it doesn't actually take longer exposures. I have asked the team internally, likely it's due to sensor tuning. Some of these very low-light cams (like the one you linked) can provide only 1-3 FPS due to such large exposure times (even multi-second exposure).

Thanks for the reply and asking internally, Erik!

The Sionyx cam actually has ~30FPS at that setting which is pretty remarkable. It's a bit unfair since they use a larger sensor, smaller FOV and bigger lens. But still, I'd think we could maybe get some performance improvement out of the 462 with some gain/ISO/exposure/… tuning 🙂

Hi @BenjaminKiefer ,
Could you try again with the latest develop? We pushed some FW changes 10 hours ago, FPS can be set down to about 0.06, and exposure set accordingly up to 15.6 seconds.

Hi @erik ,

Thanks, I just tried it out. I can lower the FPS and increase the exposure. See the following results:

This is the scene at daylight. Left is the Sionyx, right is the 462 (unfortunately behind a grid).

At night, I get the following (only 462 in the following images (isp and preview)):

With 33ms exposure and 100 ISO, I don't get anything.

I do get a better performance with exposure ~100ms and ISO 1600.

However, ISO seems to be very important for this exposure as ISO 100 yields:

This was with FPS > 10. If I set the FPS very low (~1FPS), I can get much better:

With low ISO

or high ISO

If I set a ridiculously high exposure (multiple seconds) and low FPS, I can get away with lower ISO:

However, my use-case requires roughly real-time (>20 FPS), hence it's not really usable for these low-light conditions.

For comparison, the Sionyx yields this at night at 30 FPS.

I wonder whether you think there is anything that can be done either on the firmware end or on my end. Probably a better lens would help, but is there anything else I'm missing? Or is this sensor just not good enough for these low-light conditions?

Thanks in any way!

PS.: I used rgb camera control.py with default setttings except for expsure, fps, ISO.

Hi @BenjaminKiefer ,
I'd say that is more or less as good as you can get it. Looking at datasheet, Sionyx's pixel size is like 10.7x larger than IMX462, which would be the main reason for such low-lvl performance. Just curious, how much did the Nightwave cost?

That would explain it certainly. I was just hoping to see results more along the lines of, e.g., this:

But, I understand that it's hard to compare their scenes/setups/comparisons to ours and it might very well be the same.

The Nightwave is much more expensive: ~2000€

I think this concludes it then. In case I have more information or anything related to it, I'm happy to provide them. Thanks for your help! 🙌

Hi @BenjaminKiefer ,
Thanks for sharing the info! I thought perhaps we could look into this sensor, but after seeing that pricetag - I think we're in a different market🙂

WRT Arducam's video - I'm fairly sure that's just marketing. No way (latest) iPhone has that bad low-light performance at "default" settings. Either they decreased the exposure time down to like 5ms, or used some very old iPhone.

Yes, it's quite a price. Although, I'm not sure what the "raw" sensor costs or whether it can be easily purchased in small quantities.

That makes sense 👍️

2 months later

Hi @BenjaminKiefer ,
We noticed that we haven't yet tested the conversion gain mode, which could improve low-light performance. We are now looking into it, and if it provides better results we will expose the configuration to the API.

17 days later
2 months later

The IMX462 has a HCG mode for low light. You can also consider IMX462LLR Mono, its 0.7x better in low light. The IMX485LQJ is 3.5x better in low light.

    RobvanHoeij hi! Thanks for the the note!

    Do you know of any material that showcases the difference or performance of the cam?

    It's not supported by Luxonis, is it?

      5 months later

      What lens do you have on the imx462, this can actually make a big difference. For the best low light performance you want something with around F1.0. Also any scene "contaminated" with IR light is going to make the imx462 and Sionyx appear much better than they actually are compared to human vision. Which could be happening in those low light examples from Arducam, I am not sure if the lux meters they use are sensitive to IR light. In your use case if having an IR illuminator is ok, then you will get almost daylight performance from the imx462 wherever the IR light is reaching.

      4 days later