Add supportment for non-centralized pinhole cameras data

[yulunwu0108]

Add supportment for non-centralized pinhole cameras data (like BlendedMVS).

[hbb1]

Thank you! Does it also work for centralized pinhole camera? I intend to keep the original data format unaffected.

[yulunwu0108]

@hbb1 Yes, it works for both. The added codes simply read principal point coordinates from the COLMAP cameras.txt file and apply them to calculate the projection matrix, referring to this issue.

[hbb1]

Hi, Thank you. However, the TSDF and the depth normal calculation are assumed to be used with centralized pinhole camera. It still needs some time to make some changes and tests.