endoscope calibration

[Evan0327]

Hello,

I would like to ask anyone has experence of endoscope calibration?

When taking pictures for calibration, the distance of endoscope to chaseboard should be quite small as the situation using it in practical right?

In that case anything special in the procedure compared to the normal calibration?

[Kiesel]

Hello Evan0327,

I have no experience with calibrating of an endoscope and don't know if it is even possible, because it is very special. But I would start with a hollow cube of known dimensions with a good texture inside and some known distances (perhaps scale paper), not much bigger than 10*10*10cm. I would then shoot enough shots (at least 10, better more) from the inside, from so many different positions/ perspectives as possible, I would also rotate the endoscop around its longitudinal axis for some shots. If you are lucky, the inside of the cube can be modelled with Agisoft PhotoScan and you get your calibration values.  For the lens I would expect a fisheye lens type, which can be choosen in PhotoScan's camera calibration menu for your imported cameras.

Hope it helps a little bit to start,

Kiesel

[Evan0327]

Hello Keisel,

Thanks for answering.

You provide a new idea for me. Applying a hallow cube for calibration is closer to the real situation than a planar chaseboard, though a qualified hallow cube may take some time to prepare. and in that case, the calibration accuracy values are also available?

Regards

Kun

[Kiesel]

Hello Evan0327,

if you could successful build a pointcloud and model in normal behavior, then you get your calibration values in
-  Tools/Camera Calibration Tab "Adjusted"
and your calibration errors by
-  right click on your camera in Camera Calibration dialog (seen on left side)
-  then choose "Distortion Plot"
-  then choose "Correlation" tab

And you get something like in attachments.

Regards,

Kiesel
 

[Evan0327]

Kiesel,

Thanks a lot, I will try that out and post later my result.

Regards