Assorted camera tracker improvements

- Add support for refining the camera's intrinsic parameters
  during a solve. Currently, refining supports only the following
  combinations of intrinsic parameters:

    f
    f, cx, cy
    f, cx, cy, k1, k2
    f, k1
    f, k1, k2

  This is not the same as autocalibration, since the user must
  still make a reasonable initial guess about the focal length and
  other parameters, whereas true autocalibration would eliminate
  the need for the user specify intrinsic parameters at all.

  However, the solver works well with only rough guesses for the
  focal length, so perhaps full autocalibation is not that
  important.

  Adding support for the last two combinations, (f, k1) and (f,
  k1, k2) required changes to the library libmv depends on for
  bundle adjustment, SSBA. These changes should get ported
  upstream not just to libmv but to SSBA as well.

- Improved the region of convergence for bundle adjustment by
  increasing the number of Levenberg-Marquardt iterations from 50
  to 500. This way, the solver is able to crawl out of the bad
  local minima it gets stuck in when changing from, for example,
  bundling k1 and k2 to just k1 and resetting k2 to 0.

- Add several new region tracker implementations. A region tracker
  is a libmv concept, which refers to tracking a template image
  pattern through frames. The impact to end users is that tracking
  should "just work better". I am reserving a more detailed
  writeup, and maybe a paper, for later.

- Other libmv tweaks, such as detecting that a tracker is headed
  outside of the image bounds.

This includes several changes made directly to the libmv extern
code rather expecting to get those changes through normal libmv
channels, because I, the libmv BDFL, decided it was faster to work
on libmv directly in Blender, then later reverse-port the libmv
changes from Blender back into libmv trunk. The interesting part
is that I added a full Levenberg-Marquardt loop to the region
tracking code, which should lead to a more stable solutions. I
also added a hacky implementation of "Efficient Second-Order
Minimization" for tracking, which works nicely. A more detailed
quantitative evaluation will follow.

Original patch by Keir, cleaned a bit by myself.

1 files changed, 12 insertions, 3 deletions

diff --git a/extern/libmv/libmv-capi.h b/extern/libmv/libmv-capi.h
index b71a66b73a6..d378afc5ea8 100644
--- a/extern/libmv/libmv-capi.h
+++ b/extern/libmv/libmv-capi.h
@@ -61,8 +61,14 @@ void libmv_tracksInsert(struct libmv_Tracks *libmv_tracks, int image, int track,
 void libmv_tracksDestroy(struct libmv_Tracks *libmv_tracks);
 
 /* Reconstruction solver */
+#define LIBMV_REFINE_FOCAL_LENGTH	(1<<0)
+#define LIBMV_REFINE_PRINCIPAL_POINT	(1<<1)
+#define LIBMV_REFINE_RADIAL_DISTORTION_K1 (1<<2)
+#define LIBMV_REFINE_RADIAL_DISTORTION_K2 (1<<4)
+int libmv_refineParametersAreValid(int parameters);
+
 struct libmv_Reconstruction *libmv_solveReconstruction(struct libmv_Tracks *tracks, int keyframe1, int keyframe2,
-			double focal_length, double principal_x, double principal_y, double k1, double k2, double k3);
+			int refine_intrinsics, double focal_length, double principal_x, double principal_y, double k1, double k2, double k3);
 int libmv_reporojectionPointForTrack(struct libmv_Reconstruction *libmv_reconstruction, int track, double pos[3]);
 double libmv_reporojectionErrorForTrack(struct libmv_Reconstruction *libmv_reconstruction, int track);
 double libmv_reporojectionErrorForImage(struct libmv_Reconstruction *libmv_reconstruction, int image);
@@ -80,18 +86,21 @@ void libmv_getFeature(struct libmv_Features *libmv_features, int number, double
 void libmv_destroyFeatures(struct libmv_Features *libmv_features);
 
 /* camera intrinsics */
+struct libmv_CameraIntrinsics *libmv_ReconstructionExtractIntrinsics(struct libmv_Reconstruction *libmv_Reconstruction);
+
 struct libmv_CameraIntrinsics *libmv_CameraIntrinsicsNew(double focal_length, double principal_x, double principal_y,
 			double k1, double k2, double k3, int width, int height);
 
 struct libmv_CameraIntrinsics *libmv_CameraIntrinsicsCopy(struct libmv_CameraIntrinsics *libmvIntrinsics);
 
-struct libmv_CameraIntrinsics *libmv_CameraIntrinsicsCopy(struct libmv_CameraIntrinsics *libmvIntrinsics);
-
 void libmv_CameraIntrinsicsDestroy(struct libmv_CameraIntrinsics *libmvIntrinsics);
 
 void libmv_CameraIntrinsicsUpdate(struct libmv_CameraIntrinsics *libmvIntrinsics, double focal_length,
 			double principal_x, double principal_y, double k1, double k2, double k3, int width, int height);
 
+void libmv_CameraIntrinsicsExtract(struct libmv_CameraIntrinsics *libmvIntrinsics, double *focal_length,
+			double *principal_x, double *principal_y, double *k1, double *k2, double *k3, int *width, int *height);
+
 void libmv_CameraIntrinsicsUndistortByte(struct libmv_CameraIntrinsics *libmvIntrinsics,
 			unsigned char *src, unsigned char *dst, int width, int height, float overscan, int channels);