CameraRealSense2::init() fails for realsense D405

[gkoundry]

I'm using the C++ API (no ROS) and when I call camera = new CameraRealSense2("D405"); it fails with the following error:

[ INFO] (2025-08-27 09:07:23.280) CameraRealSense2.cpp:617::init() Device Name: Intel RealSense D405
[ INFO] (2025-08-27 09:07:23.280) CameraRealSense2.cpp:620::init() Device FW version: 5.16.0.1
[ INFO] (2025-08-27 09:07:23.280) CameraRealSense2.cpp:623::init() Device Product ID: 0x0B5B
[ INFO] (2025-08-27 09:07:23.280) CameraRealSense2.cpp:633::init() Device Sensors: 
[ INFO] (2025-08-27 09:07:23.280) CameraRealSense2.cpp:701::init() Stereo Module was found.
terminate called after throwing an instance of 'rs2::error'
  what():  null pointer passed for argument "sensor"
Aborted (core dumped)

It is failing because the code expects both a RGB camera and stereo module but the D405 does not have a RGB sensor (see IntelRealSense/librealsense#11981).

[matlabbe]

It seems crashing in that loop:

rtabmap/corelib/src/camera/CameraRealSense2.cpp

Lines 625 to 694 in 52e770e

	UINFO("Device Sensors: ");
	std::vector<rs2::sensor> sensors(2); //0=rgb 1=depth 2=(pose in dualMode_)
	bool stereo = false;
	bool isL500 = false;
	for(auto&& elem : dev_sensors)
	{
	std::string module_name = elem.get_info(RS2_CAMERA_INFO_NAME);
	if ("Stereo Module" == module_name)
	{
	sensors[1] = elem;
	if(sensors[1].supports(rs2_option::RS2_OPTION_EMITTER_ENABLED))
	{
	sensors[1].set_option(rs2_option::RS2_OPTION_EMITTER_ENABLED, emitterEnabled_);
	}
	}
	else if ("Coded-Light Depth Sensor" == module_name)
	{
	}
	else if ("RGB Camera" == module_name)
	{
	if(!ir_)
	{
	sensors[0] = elem;
	}
	}
	else if ("Wide FOV Camera" == module_name)
	{
	}
	else if ("Motion Module" == module_name)
	{
	if(!dualMode_)
	{
	sensors.resize(3);
	sensors[2] = elem;
	}
	}
	else if ("Tracking Module" == module_name)
	{
	if(dualMode_)
	{
	sensors.resize(3);
	}
	else
	{
	sensors.resize(1);
	stereo = true;
	}
	sensors.back() = elem;
	sensors.back().set_option(rs2_option::RS2_OPTION_ENABLE_POSE_JUMPING, 0);
	sensors.back().set_option(rs2_option::RS2_OPTION_ENABLE_RELOCALIZATION, 0);
	}
	else if ("L500 Depth Sensor" == module_name)
	{
	sensors[1] = elem;
	isL500 = true;
	if(ir_)
	{
	cameraWidth_ = cameraDepthWidth_;
	cameraHeight_ = cameraDepthHeight_;
	cameraFps_ = cameraDepthFps_;
	}
	irDepth_ = true;
	}
	else
	{
	UERROR("Module Name \"%s\" isn't supported!", module_name.c_str());
	return false;
	}
	UINFO("%s was found.", elem.get_info(RS2_CAMERA_INFO_NAME));
	}

If you can change the source code, can you move the UINFO("%s was found.", elem.get_info(RS2_CAMERA_INFO_NAME)); at the beggining of the loop to see in which module it is crashing?

A workaround is to launch the D405 in IR mode, either IR-Depth or Stereo-IR by using these functions:

rtabmap/corelib/include/rtabmap/core/camera/CameraRealSense2.h

Lines 75 to 76 in 52e770e

	void setEmitterEnabled(bool enabled);
	void setIRFormat(bool enabled, bool useDepthInsteadOfRightImage);

camera->setEmitterEnabled(false);
camera->setIRFormat(true, true);
camera->init();

[gkoundry]

The workarounds stop it from crashing, however the RGB images are now one channel uint8 greyscale images.

The crash is not happening in the sensor loop. It it happening at

rtabmap/corelib/src/camera/CameraRealSense2.cpp

Line 706 in 6684949

UINFO("Sensor %d \"%s\"", (int)i, sensors[i].get_info(RS2_CAMERA_INFO_NAME));

due to sensors[0] not being assigned a valid sensor.

[gkoundry]

For the D405 you have one sensor with steam profiles for both RGB and depth. Rtabmap does not seem to handle this case. I was able to make some changes to support getting both depth and RGB from the same sensor:

--- a/corelib/src/camera/CameraRealSense2.cpp
+++ b/corelib/src/camera/CameraRealSense2.cpp
@@ -699,7 +699,7 @@ bool CameraRealSense2::init(const std::string & calibrationFolder, const std::st
        std::vector<std::vector<rs2::stream_profile> > profilesPerSensor(sensors.size());
         for (unsigned int i=0; i<sensors.size(); ++i)
         {
-               if(i==0 && ir_ && !stereo)
+               if(i==0) // && ir_ && !stereo)^M
                {
                        continue;
                }
@@ -760,7 +760,7 @@ bool CameraRealSense2::init(const std::string & calibrationFolder, const std::st
                                                                intrinsic.model,
                                                                intrinsic.coeffs[0], intrinsic.coeffs[1], intrinsic.coeffs[2], intrinsic.coeffs[3], intrinsic.coeffs[4]);
                                                added = true;
-                                               if(video_profile.format() == RS2_FORMAT_RGB8 || profilesPerSensor[i].size()==2)
+                                               if(profilesPerSensor[i].size()==2)^M
                                                {
                                                        break;
                                                }

Obviously this only is valid for the D405 but hopefully it helps.