sfs_mod_lr🔗
Short description🔗
sfs_mod_lr — Reconstruct a surface from a gray value image.
Signature🔗
sfs_mod_lr( image Image, out image Height, angle.deg Slant, angle.deg Tilt, number Albedo, number Ambient )
Description🔗
sfs_mod_lr reconstructs a surface (i.e. the relative
height of each image point) using the modified algorithm of Lee and
Rosenfeld. The surface is reconstructed from the input image
Image, and the light source 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.
Attention🔗
sfs_mod_lr 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_mod_lr. A Cartesian coordinate system with the origin
in the lower left corner of the image is used internally.
sfs_mod_lr can only handle byte-images.
Execution information🔗
Execution information
-
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
-
Multithreading scope: global (may be called from any thread).
-
Automatically parallelized on tuple level.
Parameters🔗
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: 0.01
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: 0.01
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
Result🔗
If all parameters are correct sfs_mod_lr returns the
value 2 (H_MSG_TRUE). Otherwise, an exception is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
estimate_al_am, estimate_sl_al_lr, estimate_sl_al_zc, estimate_tilt_lr, estimate_tilt_zc, optimize_fft_speed
Possible successors
Module🔗
3D Metrology