# How to use F(Output fundamental matrix) which is the output of stereoCalibrate?

**URL:** <https://forum.opencv.org/t/how-to-use-f-output-fundamental-matrix-which-is-the-output-of-stereocalibrate/11456>\
**Category:** C++\
**Tags:** calib3d\
**Created:** [December 30, 2022, 8:45am UTC](https://forum.opencv.org/t/how-to-use-f-output-fundamental-matrix-which-is-the-output-of-stereocalibrate/11456 "2022-12-30T08:45:46Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jumby](https://avatars.discourse-cdn.com/v4/letter/j/db5fbb/32.png) [@jumby](https://forum.opencv.org/u/jumby)\
**Post date:** [December 30, 2022, 8:45am UTC](https://forum.opencv.org/t/how-to-use-f-output-fundamental-matrix-which-is-the-output-of-stereocalibrate/11456/1 "2022-12-30T08:45:46Z")

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when i use F in pixel uv coordinate,should I undistort img or not?

I read the opencv doc,i think I need to undistort img before i use the output F.

anyway,I need confirmed,thanks:)