Alternating sequence "laser on-off" with auto-exposure

Technical Support & Q&A
1

Hi,

I would like to use a similar feature to the one of the advanced.interleave example with a Gemini 335L camera.

I am able to receive alternating frames with and without the laser projector.

I would like to tune the behavior of the auto-exposure for both frames by setting explicitly the properties, as commented out in the example code:

// The default parameters were loaded when loadFrameInterleave is called
// You can also modify these parameters yourself
//
// 1. frame interleave parameters for index 0(index starts from 0):
// device->setIntProperty(OB_PROP_FRAME_INTERLEAVE_CONFIG_INDEX_INT, 0);
// device->setIntProperty(OB_PROP_LASER_CONTROL_INT, 1);  // first: set laser control to 1 to turn on laser
// device->setIntProperty(OB_PROP_DEPTH_EXPOSURE_INT, 3000);
// device->setIntProperty(OB_PROP_DEPTH_GAIN_INT, 16);
// device->setIntProperty(OB_PROP_IR_BRIGHTNESS_INT, 60);
// device->setIntProperty(OB_PROP_IR_AE_MAX_EXPOSURE_INT, 30000);

// 2. frame interleave parameters for index 1(index starts from 0):
// device->setIntProperty(OB_PROP_FRAME_INTERLEAVE_CONFIG_INDEX_INT, 1);
// device->setIntProperty(OB_PROP_LASER_CONTROL_INT, 0);  // second: set laser control to 0 to turn off laser
// device->setIntProperty(OB_PROP_DEPTH_EXPOSURE_INT, 3000);
// device->setIntProperty(OB_PROP_DEPTH_GAIN_INT, 16);
// device->setIntProperty(OB_PROP_IR_BRIGHTNESS_INT, 60);
// device->setIntProperty(OB_PROP_IR_AE_MAX_EXPOSURE_INT, 17000);

However, it looks like that auto-exposure is only applied for the first frame of the sequence; for the other one, the exposure and gain remain very low, and the frame is mostly dark.

By the way, how do the OB_PROP_DEPTH_EXPOSURE_INT and OB_PROP_DEPTH_GAIN_INT properties combine with the OB_PROP_IR_BRIGHTNESS_INT and OB_PROP_IR_AE_MAX_EXPOSURE_INT ones? The former being for a manual exposure, and the later for auto exposure, right?

I also tried to use the OB_PROP_LASER_ON_OFF_MODE_INT property, that produces more or less the same behavior (auto-exposure settings seems to be only applied to the 1st frame of the sequence).
I haven’t really understood the difference between that mode and the interleave one though.

Could someone give me some hints how to manage alternating sequence “laser on-off” with auto exposure?

Thanks in advance!

2

Note: this is a duplicate post of Alternating sequence "laser on-off" with auto-exposure · Issue #165 · orbbec/OrbbecSDK_v2 · GitHub, that I created before I found out about this forum.

3

Additional observation: using OB_PROP_LASER_ON_OFF_MODE_INT, OB_PROP_IR_AE_MAX_EXPOSURE_INT seems to be respected by the AE mecahnism, but only for the first frame of the sequence, not for the other one.
However, the specified ROI is not taken into account in that case.