http://www.vision.caltech.edu/bouguetj/calib_doc/htmls/example.html, follow the steps in the site I am step by step, the extract grid corners (extracting angular point) and then click the calibration in the following situation the Main calibration optimization procedure - the Number of images: 13
Gradient descent iterations: 1... Warning: it appears that the principal point always be estimated. The Setting center_optim=0

Warning: the View # 1 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 2 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 3 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 4 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 6 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 7 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 8 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 9 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 10 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 11 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)

Warning: the View # 12 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)
Warning: the View # 13 ill - conditioned. This image is now set inactive. (note: the to disactivate This option, the set check_cond=0)
2... The Intrinsic parameters at frame 1 do not exist
New optimization o the images that have had been deactivated during the previous optimization.

The Aspect thewire optimized (est_aspect_ratio=1) - & gt; Both the components of the fc are estimated (DEFAULT).
The Principal point not optimized (center_optim=0). Note: to set it in the middle of the image, the clear variable cc, and run calibration again.
Skew the not optimized (est_alpha=0) - (DEFAULT)
Distortion not fully estimated (defined by the variable est_dist) :
Sixth order distortion not estimated (est_dist (5)=0) - (DEFAULT).
Says I can't optimize the main point, to set up in the middle, don't know what that means, is there which had a similar problem, help ah (online as if no such answer)