grey_moments ( Regions, Image : : : MRow, MCol, Alpha, Beta, Mean )
Calculate gray value moments and approximation by a plane.
The operator grey_moments calculates the gray value
moments and the parameters of the approximation of the gray values
by a plane. The calculation is carried out according to the
following formula:
MRow = sum((r-r')*(Image(r,c)-Mean))/F^2
MCol = sum((c-c')*(Image(r,c)-Mean))/F^2
Alpha = (MRow*F*m02-m11*MCol*F)/(m20*m02-m11^2)
Beta = (m20*MCol*F-MRow*F*m11)/(m20*m02-m11^2)
where F is the plane, r', c' the center, and m11, m20, and m02 the
normalized moments of Regions.
The parameters Alpha, Alpha and
Mean describe a plane above the region:
Image'(r,c) = Alpha*(r-r')+Beta*(c-c')+Mean
Thus Alpha indicates the gradient in the direction of the
line axis (``down''), Beta the gradient in the direction
of the column axis (to the ``right'').
Parameters
Regions (input_object)
|
region(-array) -> object
|
Regions to be checked. |
Image (input_object)
|
image -> object : byte
|
Corresponding gray values. |
MRow (output_control)
|
real(-array) -> real
|
Mixed moments along a line. |
MCol (output_control)
|
real(-array) -> real
|
Mixed moments along a column. |
Alpha (output_control)
|
real(-array) -> real
|
Parameter Alpha of the approximating plane. |
Beta (output_control)
|
real(-array) -> real
|
Parameter Beta of the approximating plane. |
Mean (output_control)
|
real(-array) -> real
|
Mean gray value. |
Result
The operator grey_moments returns the value TRUE if an
image with the defined gray values (byte) is entered and
the parameters are correct. The behavior in case of empty input (no
input images available) is set via the operator
set_system(::'no_object_result',<Result>:), the behavior
in case of empty region is set via
set_system(::'empty_region_result',<Result>:).
If necessary an exception is raised.
Possible Predecessors
draw_region,
circle,
ellipse,
rectangle1,
rectangle2,
threshold__,
regiongrowing__
Possible Successors
image_plane
See also
intensity__,
moments
References
R. Haralick, L. Shapiro; "Computer and Robot Vision";
Addison-Wesley, 1992, Seite 75-76
Copyright © 1996-1997 MVTec Software GmbH