Strange… but i've found the solution.

It is likely that the problem is caused by the camera calibration which is optimized for laptop camera. due to some properties of mobile phone cameras, the camera calibration may not be accurate.

Unlike many software licenses, the GPL encourages releasing modified versions. You should do what you’re comfortable with. If you release a GPL-covered work without making the source code available, people can still run the program and see what it does. But if they improve on it, or make changes to fix bugs, they cannot share those changes with you or others unless you also provide your source code.