Camera flicker at constant illumination?

We testing our camera in light box, and turn AE=on. But found camera flicker, especially when EV value is adjusted down(such as ev=2 to ev=1). We checked the camera driver log and found gain setting is jumped between 1-3…

It’s could be the sensor gain 1-3 didn’t linearity cause the AE problem.

We have measured curve of Y value of image and setting gain, as following…
It seems ok…
image

In some scenes, exposure time(exposure line) also jumps between 2-3?

exposure_line_jump_2_3.log (6.6 MB)

Could you measure by smaller scaler like 1.0, 1.1 … 3.0, …3.5

Only integer gain used by us…

step_gain_val = 1
gain_factor = 1

Also, we disable ISP digital gain…

Range<float> range = Range<float>(1.0f, 1.0f);
setIspDigitalGainRange(range);

@ShaneCCC
Is there other things to check?

Thanks.

Could be gain scaler too big cause the issue.

Hi, ShaneCCC:
We did not set gain_factor in dts, and use the default value of 1.
So:
when gain=1, means gain is 1.0
when gain=2, means gain is 2.0

Yes, I know. I mean it could be the gain step too big cause the problem.

Is there way to decrease gain step?

Thanks…

If the sensor REG unable support smaller scaler may need to find other solution.
Maybe contact with camera partner to do verify the gain/exposure linearity by tools.

@ShaneCCC
So, can we draw such conclusion:
If sensor only supports integer gains, AE of tx2 has a possbility of flickering?

Thanks

I guess that could be the reason.

I will try it.

But these’re also a little flickering, when exposure time switching between 2 and 3 exposure lines…