Manual exposure control with libargus

Autonomous Machines Jetson & Embedded Systems Jetson TX1
1

Hi there,

We’re using libargus to capture image RGB data on TX1/28.2; the normal workflow is to capture four sequential frames and stop, and wait for next session. It works so far; now we need to fine-tune the exposure. However, all parameter changes we tried didn’t seem to change the captured image much. We’re wondering if there’s a manual exposure mode in libargus, so the exposure could be adjusted manually?

Thanks,

Steven

3

hello stevenhliu,

if you enable argus_camera application, there’s UI to configure exposure time ranges.
you may also refer to Argus sample, userAutoExposure to demonstrate APIs for settings exposure values.
thanks

4

Hi Jerry,

Thank you for getting back to me. I went through userAutoExposure sample, and incorporated the exposure parameter controls into my application, and there’s no error msgs, so it looks argus library took the parameters ok, it’s just they didn’t affect the captures much. I noticed userAutoExposure takes 500 captures, while mine takes only four; and the doc somewhere says it’ll take two frames for the new parameter to take effect, off my head. I tried capturing six frames, and didn’t see the effect. Is it possible it’ll take quite a few frames for the exposure parameter to take effect? If yes, how many?

Thanks,

Steven

5

hello stevenhliu,

suggest you should enable gstreamer pipeline to adjust the exposure time range for verify your manually exposure functionality.
for example, you may check the element properties.

$ gst-inspect-1.0 nvarguscamerasrc
...

  exposuretimerange   : Property to adjust exposure time range in nanoseconds
                        Use string with values of Exposure Time Range (low, high)
                        in that order, to set the property.
                        eg: exposuretimerange="34000 358733000"

please enable camera previews at fix exposuretimerange (low=high) to confirm the functionality.
thanks

6

Will try that. Thanks for the suggestion.

-Steven