* Added CALIB_FIX_FOCAL_LENGTH to fisheye calibration #13450
Sometimes you want to calibrate just the principal point of a camera, or just the distortion coefficients. In this case, you can pass the CALIB_FIX_FOCAL_LENGTH flag to keep Fx and Fy
* Added test for CALIB_FIX_FOCAL_LENGTH option in fisheye callinration.
fix instable fisheye undistortPoints
* remove artefacts when (un)distorting fisheye images with large distortion coefficient values
* fix fisheye undistortion when theta is close to zero
* add fisheye image undistort and distort test
* Fixed type conversion warnings
* fixed trailing whitespace
* Newton's method can be more efficient
when we get the result of function distortPoint with a point (0, 0) and then undistortPoint with the result, we get the point not (0, 0). and then we discovered that the old method is not convergence sometimes. finally we have gotten the right values by Newton's method.
* modify by advice Newton's method...#10574
* calib3d(fisheye): fix codestyle, update theta before exit EPS check
Remove unnecessary Non-ASCII characters from source code (#9075)
* Remove unnecessary Non-ASCII characters from source code
Remove unnecessary Non-ASCII characters and replace them with ASCII
characters
* Remove dashes in the @param statement
Remove dashes and place single space in the @param statement to keep
coding style
* misc: more fixes for non-ASCII symbols
* misc: fix non-ASCII symbol in CMake file
The old error message was not giving any hint which input array (image)
led to an ill conditioned matrix. This made it near impossible to
identify poor images in a larger set.
A better approach would be to implement a checker function which gives
each image a rating before the real calibration is performed. This could
also include some image properties like sharpness, etc.
the current camera model is only valid up to 180° FOV for larger FOV the
undistort loop does not converge.
Clip values so we still get plausible results for super fisheye images >
180°.
Fix for inconsistent asserts in cv::fisheye::initUndistortRectifyMap() which prevents from passing empty matrices in debug build (which is allowed according to the code bellow the asserts and the docs).
