Segmentation fault when using aruco.DetectorParameters

[prensing]

Expected behaviour

I am not sure if I am just doing something wrong, but I definitely don't expect a seg fault.

I have install opencv-contrib-python version 4.6.0.66 from the pip wheel. I then try this:

$ python3 -c 'import cv2; x = cv2.aruco.DetectorParameters(); x.aprilTagQuadDecimate = 2.0'
Segmentation fault (core dumped)

This is in Linux Mint 21.
python 3.10

Actual behaviour

$ python3 -c 'import cv2; x = cv2.aruco.DetectorParameters(); x.aprilTagQuadDecimate = 2.0'
Segmentation fault (core dumped)

Steps to reproduce

OS: LInux 64-bit, Linux Mint
Python 3.10
opencv-contrib-python installed from PyPi

Any access to fields in DetectorParameters seems to cause this crash.

Issue submission checklist

• [ x] This is not a generic OpenCV usage question (looking for help for coding, other usage questions, homework etc.)
• [x ] I have read the README of this repository and understand that this repository provides only an automated build toolchain for OpenCV Python packages (there is no actual OpenCV code here)
• [ x] The issue is related to the build scripts in this repository, to the pre-built binaries or is a feature request (such as "please enable this additional dependency")
• [ x] I'm using the latest version of opencv-python

[AleksandrPanov]

@prensing, use static create method: x = cv2.aruco.DetectorParameters_create()
this will fix your problem

[prensing]

Thanks. That does seem to fix the problem. May I suggest that you add a bit to the documentation? At least from Python, there is no way to tell that the "constructor" does not actually produce a valid instance.

Thanks for the support!!