[Elphel-support] Exposure priority

[Dimitrios]

Hi Oleg.
Thank you for the quick reply.

> scene is not blurred. Different default gains for sunny/cloudy
> conditions might work. What do you think?

Yes, I do exactly this with gain presets and works fine. I might try to
implement an algorithm for 'exposure priority', but it'll have to be
external to the camera for now, and I guess the latency will not be very
small. I see two versions of the 'exposure priority':

1. Lax: auto-adjust gain (within limits, e.g. max 8) and if at the upper
limit, then adjust exposure.
2. Strict: auto-adjust gain and if at the  upper limit do nothing.

This brings a few more questions:

- Is the 'gain-priority' algorithm implemented in the FPGA? If not,
could you please point me to the source file where I can find it?

- Camvc parameters ae, aef and ael set auto-exposure, auto-exposure
level and auto-exposure fraction, as I can tell by looking at the AJAX
requests sent by the browser to the camera. What is the parameter/tag
for the actual percentage of pixels below ael in the response XML? Would
that be the <hist_out> family of values? I see the <hist_out_g> value
very close to the one reported in camvc's screen.

Regards
Dimitrios