find_caltab ( Image : Caltab : CalTabDescrFile, SizeGauss, MarkThresh : )
Segmentation of the calibration table region in the image.
find_caltab is used to determine the region of a plane
calibration table with circular marks in the input image Image.
This is done by first smoothing the input image (see gauss__);
the size of the used filter mask is given by SizeGauss.
Afterwards a thresholding operator (see threshold__)
with minimum grey value MarkThresh and maximum grey value
255 is applied. The result of find_caltab is the most convex
region with the correct number of holes among all the remaining regions.
The correct number of holes corresponds to the number of marks on
the calibration table and is read from the calibration table description
file CalTabDescrFile. The complete explanation of this file
can be found by the description of create_caltab.
Parameters
Image (input_object)
|
image -> object : byte
|
Input image. |
Caltab (output_object)
|
region -> object
|
Output region. |
CalTabDescrFile (input_control)
|
string -> string
|
File name of the calibration table description. |
Default value: 'caltab.descr' |
SizeGauss (input_control)
|
integer -> integer
|
Filter size of the Gaussian. |
Default value: 3 |
List of values: 3, 5, 7, 9, 11, 13 |
MarkThresh (input_control)
|
integer -> integer
|
Threshold value for mark extraction. |
Default value: 112 |
List of values: 48, 64, 80, 96, 112, 128, 144, 160 |
Example
/* read calibration image */
read_image(:Image:'calib-01.tiff':) >
/* find calibration pattern */
find_caltab(Image:Caltab:'caltab.descr',3,112:).
Result
find_caltab returns TRUE if all parameter values are
correct and a image region is found. The behavior in case
of empty input (no image given) can be set via
set_system(::'no_object_result',<Result>:)
and the behavior in case of an empty result region via
set_system(::'store_empty_region',<true/false>:).
If necessary an exception is raised.
Possible Predecessors
read_image
Possible Successors
find_marks_and_pose
See also
find_marks_and_pose,
camera_calibration,
disp_caltab,
sim_caltab,
caltab_points,
create_caltab
Copyright © 1996-1997 MVTec Software GmbH