sfs_pentland — Reconstruct a surface from a gray value image.
sfs_pentland reconstructs a surface (i.e. the relative
height of each image point) using the algorithm of Pentland. The
surface is reconstructed from the input image Image.
The light source must be given by the parameters Slant,
Tilt, Albedo and Ambient, and is
assumed to lie infinitely far away in the direction given by
Slant and Tilt. The parameter
Albedo determines the albedo of the surface, i.e. the
percentage of light reflected in all directions. Ambient
determines the amount of ambient light falling onto the surface. It
can be set to values greater than zero if, for example, the white
balance of the camera was badly adjusted at the moment the image was
taken.
sfs_pentland assumes that the heights are to be extracted on
a lattice with step width 1. If this is not the case, the
calculated heights must be multiplied with the step width after the
call to sfs_pentland. A Cartesian coordinate system with
the origin in the lower left corner of the image is used internally.
sfs_pentland can only handle byte-images.
Image (input_object) singlechannelimage(-array) → object (byte)
Shaded input image.
Height (output_object) image(-array) → object (real)
Reconstructed height field.
Slant (input_control) angle.deg → (real / integer)
Angle between the light source and the positive z-axis (in degrees).
Default: 45.0
Suggested values: 1.0, 5.0, 10.0, 20.0, 40.0, 60.0, 90.0
Value range:
0.0
≤
Slant
≤
180.0 (lin)
Minimum increment: 1.0
Recommended increment: 10.0
Tilt (input_control) angle.deg → (real / integer)
Angle between the light source and the x-axis after projection into the xy-plane (in degrees).
Default: 45.0
Suggested values: 1.0, 5.0, 10.0, 20.0, 40.0, 60.0, 90.0
Value range:
0.0
≤
Tilt
≤
360.0 (lin)
Minimum increment: 1.0
Recommended increment: 10.0
Albedo (input_control) number → (real / integer)
Amount of light reflected by the surface.
Default: 1.0
Suggested values: 0.1, 0.5, 1.0, 5.0
Value range:
0.0
≤
Albedo
≤
5.0 (lin)
Minimum increment: 0.01
Recommended increment: 0.1
Restriction:
Albedo >= 0.0
Ambient (input_control) number → (real / integer)
Amount of ambient light.
Default: 0.0
Suggested values: 0.1, 0.5, 1.0
Value range:
0.0
≤
Ambient
≤
1.0 (lin)
Minimum increment: 0.01
Recommended increment: 0.1
Restriction:
Ambient >= 0.0
If all parameters are correct sfs_pentland returns the
value 2 (
H_MSG_TRUE)
. Otherwise, an exception is raised.
estimate_al_am,
estimate_sl_al_lr,
estimate_sl_al_zc,
estimate_tilt_lr,
estimate_tilt_zc,
optimize_fft_speed
3D Metrology