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48 lines
2.6 KiB
48 lines
2.6 KiB
Camera Models
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=============
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COLMAP implements different camera models of varying complexity. If no intrinsic
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parameters are known a priori, it is generally best to use the simplest camera
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model that is complex enough to model the distortion effects:
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- ``SIMPLE_PINHOLE``, ``PINHOLE``: Use these camera models,
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if your images are undistorted a priori. These use one and two focal length
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parameters, respectively. Note that even in the case of undistorted images,
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COLMAP could try to improve the intrinsics with a more complex camera model.
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- ``SIMPLE_RADIAL``, ``RADIAL``: This should be the camera model of choice,
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if the intrinsics are unknown and every image has a different camera
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calibration, e.g., in the case of Internet photos. Both models are simplified
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versions of the ``OPENCV`` model only modeling radial distortion
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effects with one and two parameters, respectively.
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- ``OPENCV``, ``FULL_OPENCV``: Use these camera models, if
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you know the calibration parameters a priori. You can also try to let COLMAP
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estimate the parameters, if you share the intrinsics for multiple images. Note
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that the automatic estimation of parameters will most likely fail, if every
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image has a separate set of intrinsic parameters.
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- ``SIMPLE_RADIAL_FISHEYE``, ``RADIAL_FISHEYE``, ``OPENCV_FISHEYE``, ``FOV``,
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``THIN_PRISM_FISHEYE``: Use these camera models for fisheye lenses
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and note that all other models are not really capable of modeling the
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distortion effects of fisheye lenses. The ``FOV`` model is used by
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Google Project Tango (make sure to not initialize `omega` to zero).
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You can inspect the estimated intrinsic parameters by double-clicking specific
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images in the model viewer or by exporting the model and opening the
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`cameras.txt` file.
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To achieve optimal reconstruction results, you might have to try different
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camera models for your problem. Generally, when the reconstruction fails and the
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estimated focal length values / distortion coefficients are grossly wrong, it is
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a sign of using a too complex camera model. Contrary, if COLMAP uses many
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iterative local and global bundle adjustments, it is a sign of using a too
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simple camera model that is not able to fully model the distortion effects.
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You can also share intrinsics between multiple
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images to obtain more reliable results
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(see :ref:`Share intrinsic camera parameters <faq-share-intrinsics>`) or you can
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fix the intrinsic parameters during the reconstruction
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(see :ref:`Fix intrinsic camera parameters <faq-fix-intrinsics>`).
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Please, refer to the camera models header file for information on the parameters
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of the different camera models:
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https://github.com/colmap/colmap/blob/master/src/base/camera_models.h
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