# Fabs(sc) \> DBL\_EPSILON

**URL:** <https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324>\
**Category:** C++\
**Created:** [May 27, 2023, 12:07am UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324 "2023-05-27T00:07:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![wanless](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/wanless/32/7965_2.png) [@wanless](https://forum.opencv.org/u/wanless)\
**Post date:** [May 27, 2023, 12:07am UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324/1 "2023-05-27T00:07:41Z")

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Hi when I run CalibrateCamera I get this error fabs(sc) \> DBL\_EPSILON.

To try solve the issue I have reduced the Calibration set of images to 1 checkerboard image 11 squares by 8.

I am passing an obj\_points array of 1 item containing 70 sets of x,y,z all 0 value, a img\_points array of 1 item containing 70 sets of x,y values all with numeric values, a size object containing a width of 640 and a height of 480.

Does anyone have any ideas to point me in the right direction on this one so I can get the calibration sorted.

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**Author:** ![wanless](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/wanless/32/7965_2.png) [@wanless](https://forum.opencv.org/u/wanless)\
**Post date:** [May 27, 2023, 12:19am UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324/2 "2023-05-27T00:19:59Z")

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This is the test image i am using to test the calibration function after i have run DrawChessboardCorners

 ![test](https://us1.discourse-cdn.com/flex020/uploads/opencv/original/2X/2/2245bba4a944c4f5b0413a7d5c508fd29ec33a6a.jpeg)

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**Author:** ![berak](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@berak](https://forum.opencv.org/u/berak)\
**Post date:** [May 27, 2023, 4:37am UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324/3 "2023-05-27T04:37:57Z")

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> [@wanless](#):
>
> I get this error fabs(sc) \> DBL\_EPSILON.

show _complete_ error msg, please

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**Author:** ![crackwitz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/crackwitz/32/14_2.png) [@crackwitz](https://forum.opencv.org/u/crackwitz)\
**Post date:** [May 27, 2023, 11:29am UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324/4 "2023-05-27T11:29:07Z")

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A single frontally viewed board will never be enough for a calibration.

It’s complaining because it _can’t_ calculate a solution from the data.

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**Author:** ![wanless](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/wanless/32/7965_2.png) [@wanless](https://forum.opencv.org/u/wanless)\
**Post date:** [May 27, 2023, 10:39pm UTC](https://forum.opencv.org/t/fabs-sc-dbl-epsilon/13324/5 "2023-05-27T22:39:16Z")

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Thank you and apologies for the confusion, I was initially using 40 images to calibrate the camera but when I hit the issue I reduced it to 1 simple chessboard image not to carry out the calibration but just to test the error.

I have managed to track down and solve the bug and it was all my fault I was using incorrect values in the obj\_points array and now my calibration seems to work.