# Fisheye Chess calibration with fix pixel aspect ration of 1 - HOW?

**URL:** <https://forum.opencv.org/t/fisheye-chess-calibration-with-fix-pixel-aspect-ration-of-1-how/3410>\
**Category:** Uncategorized\
**Tags:** fisheye, calibration\
**Created:** [May 19, 2021, 9:01am UTC](https://forum.opencv.org/t/fisheye-chess-calibration-with-fix-pixel-aspect-ration-of-1-how/3410 "2021-05-19T09:01:27Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Gal\_Oz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/gal_oz/32/2142_2.png) [@Gal\_Oz](https://forum.opencv.org/u/Gal_Oz)\
**Post date:** [May 19, 2021, 9:01am UTC](https://forum.opencv.org/t/fisheye-chess-calibration-with-fix-pixel-aspect-ration-of-1-how/3410/1 "2021-05-19T09:01:27Z")

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Hi,  
I am using a wide-angle lens and the Fisheye model works the best for me.  
when I doing the chess calibration with the Fisheye class I can’t find a flag that forces the pixel to have an aspect ratio of 1.  
for the standard model calibration, I do have a flag of “CALIB\_FIX\_ASPECT\_RATIO” but not for the fisheye.  
any idea?