Exposure tuning (nightpreview)

[nopmop]

Problem
my problem is dark images - I'm aware of the FPS<->light relationship (as detailed at #12) and of possible workarounds (like using an RTSP server as detailed here #165, which hammers the CPU considerably though).

Solution i'd like
Being able to tune the mmal exposure parameter (set to nightpreview for example) from kerberosio would be nice.

Question
Is this going to be contemplated for a future release? Where to look in the code to submit a PR?

[nopmop]

Bump. Any help?

[cedricve]

hey @nopmop, this is a hard one. You will need to consider looking into this https://github.com/dridri/OpenMaxIL-cpp

[gbus]

Hi @cedricve
I have just added support for setExposureControl in https://github.com/dridri/OpenMaxIL-cpp.
I have tested it from kerberos.io with this simple change, but I guess that it takes you 5 minutes to make it configurable from the raspicam settings in capture.xml:

diff --git a/src/kerberos/capture/RaspiCamera.cpp b/src/kerberos/capture/RaspiCamera.cpp
index 07c1a97..f17ef9c 100755
--- a/src/kerberos/capture/RaspiCamera.cpp
+++ b/src/kerberos/capture/RaspiCamera.cpp
@@ -218,7 +218,7 @@ namespace kerberos
 				state.camera->setSaturation(m_saturation);
 				state.camera->setContrast(m_contrast);
 				state.camera->setSharpness(m_sharpness);
-				//state.camera->setExposureControl(Camera::ExposureControlOff);
+				state.camera->setExposureControl(Camera::ExposureControlNight);
 
 				if(m_angle > 0)
 				{

Thanks

[cedricve]

super cool @gbus, do you have any results already?

[gbus]

Yes, with ExposureControlNight the image from a room with little light looked very bright, while with ExposureControlSnow was totally dark.
:-)

[cedricve]

Cool ! and what about the recording speed, just curious. How much FPS do you get.
Will definitely check this out myself. Great job!!

[gbus]

I tried 1,3,5,10,20,30 fps, where at 10fps the exposure was similar to what I could see with my bare eyes. I would consider 1, 3 and 5fps like 3 possible level of exposure improvement (and image quality).
Here are the sample pictures: