How to extract raw stereo images(left and right camera images) from database created by Rtabmap.

[skitmanish]

Could you please let me know if the RTAB-Map database has a specific field that stores the left and right camera images from the stereo setup? If so, what is the field name, and how can it be accessed?

Thanks!

[matlabbe]

You can use rtabmap-databaseViewer and do File -> Extract images...

You can also use rtabmap-export --images rtabmap.db.

If you want to extract yourself from the database, they are compressed blob that can be decoded by opencv's imdecode function:

rtabmap/corelib/src/resources/DatabaseSchema.sql.in

Lines 33 to 34 in 618e839

	image BLOB, -- compressed image (Grayscale or RGB)
	depth BLOB, -- compressed image (Depth or Right image)

(depth is the right image in a stereo config)

[skitmanish]

Hi, thank you for the quick response!

I have another question:

I am running Rtabmap with local stereo images and want to store the exact same images I provided as input. I used the Data Recorder tool to store raw data, but I noticed that the right images in the exported database are grayscale and resized based on the provided decimation. I need the images to be stored in their original size and in color. Is there a way to achieve this?

[matlabbe]

Don't provide decimation to keep same resolution. To keep the right image as rgb, you may have to hard-code the output encoding here to bgr8 instead of mono8:
https://github.com/introlab/rtabmap_ros/blob/a57b2971f2079d375f867bdb6927efefd75ddd38/rtabmap_conversions/src/MsgConversion.cpp#L2494
However, I am not totally sure at 100% that it would not cause any issue.

[matlabbe]

Added a PR to support right color image downstream: #1463