3A ISO and exposure time limits

Timm

Hi,

I'm using my OAK-D Lite outdoors and have never observed the exposure time go below 1 ms or the ISO go above 1200, even though some of the images I've acquired suggest that at times one or the other would have been beneficial.

Is it correct that the 3A algorithm should be able to go lower the exposure time to about 100 us? And is there any documentation regarding the 3A's ISO limits?

Thanks,
Tim

jakaskerl

Timm
Reading through the sensor config, I think it should be possible to go as low as 100us. Can you try manually setting the exposure time to 100us to check? There should be a warning if too low value is set.

Thanks,
Jaka

Timm

Hi @jakaskerl,

Manually setting the exposure time to 100 us works. It just never went lower than 1 ms on its own, yet. Can the 3A algorithm drive it to values below 1 ms?

Also, does the 3A algorithm have any ISO limits? It doesn't seem to want to go higher than 1200, even though sometimes the images pretty dark.

Thanks,
Tim

jakaskerl

Hi @Timm
There's setAutoExposureLimit(), but afaik this only sets the upper limit of the exposure time.

cc @Luxonis-Alex

Thanks,
Jaka

Timm

Hi @jakaskerl,

Thanks for your quick response! Just a quick clarification, I'm interested in whether there are any ISO/exposure time restrictions built into the 3A algorithm that the user cannot change. For example, I can manually set the ISO to 1600, but when when the ISO is set automatically, I've never seen it go below 1200, regardless of how dark it gets.

Cheers,
Tim