Welcome new user! You can search existing questions and answers without registering, but please register to post new questions and receive answers. Note that due to large amounts of spam attempts, your first three posts will be manually moderated, so please be patient.
Because of un-manageable amounts of spam despite our use of CAPTCHAs, email authorization, and other tools, we have discontinued this forum (see the 700k+ registered users with validated email addresses at right?). Please email us any questions or post bug reports and feature requests on GitHub at https://github.com/jevois -- The content below remains available for future reference.
Welcome to JeVois Tech Zone, where you can ask questions and receive answers from other members of the community.

Camera module seems poor in low light.

0 votes

I am seeing quite a lot of noise (due to high gain?) in the video and the camera image is quite dark.

I also have quite poor white balance. (white looks yellow).

Compared to a 12M pixel 'spy' camera dvr from ebay (similar tiny camera module) the Jevois camera is very poor in moderate light conditions.

Very cheap 12Mpixel mini spy camera:

And the JeVois:

You can just barely make out the picture frame.

And you can see a lot noise in the image.

The yellow cast is also present.

Are there adjustments I need to make?

asked May 23, 2017 in Hardware Questions by rich111 (120 points)

1 Answer

+1 vote
Yes, we will post a new doc page about this soon because a few peole have asked.

First of all, the sensor is indeed not very fancy and not the best in low light, but there are things you can do to help. Make sure you have the latest version of the microSD image from jevois.org/start as the one we shipped with pre-loaded cards (which were made a while back) did not yet have the latest enhanced settings.

1. try a lower framerate. In most demos we used 60fps because I like that speed, but if you are happy with 15fps then you will get much more available exposure time and you should do much better in low light. I suspect your other camera is not running at 60fps? You can try it by comparing the 320x240@60fps of the SaveVideo that you took a shot of to, e.g., 320x260@30fps of DemoArUco. As you change resolution you should see the autogain brighten the image and the noise should be less prominent. Then edit JEVOIS:/config/videomappings.cfg and change the frame rate to 15fps in some module of your choice (set both the USB and the Camera rates to 15) and see how well that works.

2. Try the manual settings. As noted in another thread, there is no autogain setting defined in the USB Video Class specs, so we coupled autogain and auto exposure. When you go to manual exposure, you will also get manual gain. Here we are able to get quite good low-light performance in manual exposure and gain modes. We crank the exposure to the max and then the gain to the minimum we can live with in terms of noise.

For the color balance, on some camera software auto white balance starts in off mode so you have to turn it on manually, you should see the color balance change as you switch it on if it was off.
answered May 23, 2017 by JeVois (46,580 points)
OK, I will try 15fps.

I wonder if the camera might be upgradable? I assume it's a CSI-2 interface?

For V2, a composite video input would be really useful. It would allow wide range of standard cctv cameras to be used.
No, it's a parallel digital interface, not CSI. You can find the datasheets for the OV9650 online pretty easily, as well as the pinouts for the FFC module. The tricky part in replacing the sensor is finding a module that has the same connector pinout - pretty much every omnivision module  is different. And getting one custom made would be expensive.