This program estimates the tangent vector to a set of 3D integer points, which are supposed to approximate a 3D curve.

Usage: ./estimators/3dCurveTangentEstimator [options] –input <filename>

This program estimates the tangent vector to a set of 3D integer points, which are supposed to approximate a 3D curve. This set of points is given as a list of points in file <input>. The tangent estimator uses either the digital Voronoi Covariance Measure (VCM) or the 3D lambda-Maximal Segment Tangent (L-MST). This program can also displays the curve and tangent estimations, and it can also extract maximal digital straight segments (2D and 3D).

Note: It is not compulsory for the points to be ordered in sequence, except if you wish to compute maximal digital straight segments. In this case, you can select the connectivity of your curve between 6 (standard) or 26 (naive).

Allowed options are :

Positionals:
  1 TEXT:FILE REQUIRED                  the name of the text file containing the list of 3D points: (x y z) per line.
 
Options:
  -h,--help                             Print this help message and exit
  -i,--input TEXT:FILE REQUIRED         the name of the text file containing the list of 3D points: (x y z) per line.
  -V,--view TEXT=OFF                    toggles display ON/OFF
  -b,--box INT=0                        specifies  the tightness of the bounding box around the curve with a given integer displacement <arg> to enlarge it (0 is tight)
  -v,--viewBox TEXT:{WIRED,COLORED}=WIRED
                                        displays the bounding box, <arg>=WIRED means that only edges are displayed, <arg>=COLORED adds colors for planes (XY is red, XZ green, YZ, blue).
  -T,--connectivity TEXT:{6,26}=6       specifies whether it is a 6-connected curve or a 26-connected curve: arg=6 | 26.
  -C,--curve3d                          displays the 3D curve
  -c,--curve2d                          displays the 2D projections of the 3D curve on the bounding box
  -3,--cover3d                          displays the 3D tangential cover of the curve
  -2,--cover2d                          displays the 2D projections of the 3D tangential cover of the curve
  -t,--tangent                          displays the tangents to the curve.
  -n,--nbColors UINT=3                  sets the number of successive colors used for displaying 2d and 3d maximal segments (default is 3: red, green, blue)
  -R,--big-radius FLOAT=10              the radius parameter R in the VCM estimator.
  -r,--small-radius FLOAT=3             the radius parameter r in the VCM estimator.
  -m,--method TEXT:{VCM,L-MST}=VCM      the method of tangent computation: VCM (default), L-MST.
  -a,--axes TEXT:{ON,OFF}=OFF           show main axes - prints list of axes for each point and color points color = (if X => 255, if Y => 255, if Z => 255)
  -o,--output TEXT=3d-curve-tangent-estimations
                                        the basename of the output text file which will contain points and tangent vectors: (x y z tx ty tz) per line

Example: This command line show an example of tangent estimation with the VCM estimator.

3dCurveTangentEstimator ${DGtal}/examples/samples/sinus.dat -V ON -c -R 20 -r 3 -T 6

DGtal

Definition: ATu0v1.h:57

You should obtain such a result:

Resulting tangent vectors (red) obtained with the VCM estimator.

See also: 3dCurveTangentEstimator.cpp