invariances ( : : RealCoef, ImaginaryCont2, NormPar, InvarType : RealInvar, ImaginaryInvar )
Normalizing of the Fourier coefficients.
Elimination of affine information from the Fourier coefficients,
determination of affine invariants. The Fourier coefficients will be
normalized suitably so that all affine contours to themselves will be
projected to one and the same contour. The following levels of affine
mappings are available:
Translations (InvarType = 'transl_invar')
+ Rotations (InvarType = 'congr_invar')
+ Scalings (InvarType = 'simil_invar')
+ Slanting (InvarType = 'affine_invar')
The control parameter InvarType indicates with regard to
which level the affine representation shall be normalized. Please note
that indicating a certain level implies that the normalizing is
executed with regard to all underlying levels. For most applications
a subsequent normalizing of the starting point is recommendable!
Parameters
RealCoef (input_control)
|
real-array -> real
|
Real parts of the Fourier coefficients. |
ImaginaryCont2 (input_control)
|
real-array -> real
|
Imaginary parts of the Fourier coefficients. |
NormPar (input_control)
|
integer -> integer
|
Input of the normalizing coefficients. |
Default value: 1 |
Suggested values: 1, 2 |
Restriction: NormPar >= 1 |
InvarType (input_control)
|
string -> string
|
Indicates the level of the affine mappings. |
Default value: 'affine_invar' |
List of values: 'affine_invar', 'simil_invar', 'congr_invar', 'transl_invar' |
RealInvar (output_control)
|
real-array -> real
|
Real parts of the normalized Fourier coefficients. |
ImaginaryInvar (output_control)
|
real-array -> real
|
Imaginary parts of the normalized Fourier coefficients. |
Example
create_param_cont(trow,tcol,"unsigned_area",¶m_scale);
fourier_1dim(trow,tcol,param_scale,&frow,&fcol);
invariances(frow,fcol,1,"affine_invar",&invrow,&invcol);
absolute_invariant(invrow,invcol,1,2,"az_invar1",&absrow,&abscol);
Possible Predecessors
fourier_1dim
Possible Successors
invariances
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