info_smooth ( : : Filter, Alpha : Size, Coeffs )
Information on smoothing filter smooth__.
The operator info_smooth returns an estimation of the
width of the smoothing filters used in routine smooth__.
For this purpose the underlying continuous impulse answers of
Filter are scanned until a filter coefficient is smaller
than five percent of the maximum coefficient (at the origin).
Alpha is the filter parameter (see smooth__).
Currently four filters are supported (parameter Filter):
'deriche1', 'deriche2', 'shen' und 'gauss'.
The gauss filter was conventionally implemented with filter masks
(the other three are recursive filters). In the case of the gauss
filter the filter coefficients (of the one-dimensional impulse
answer f(n) with n >= 0) are returned
in Coeffs in addition to the filter size.
Parameters
Filter (input_control)
|
string -> string
|
Name of required filter. |
Default value: 'deriche2' |
List of values: 'deriche1', 'deriche2', 'shen', 'gauss' |
Alpha (input_control)
|
real -> real
|
Filter parameter: small values effect strong
smoothing (reversed in case of 'gauss'). |
Default value: 0.5 |
Suggested values: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.0, 10.0 |
Range of values: 0.01 <= Alpha <= 50.0 |
Minimum increment: 0.01
|
Recommended increment: 0.1
|
Restriction: Alpha > 0.0 |
Size (output_control)
|
integer -> integer
|
Width of filter is approx. size x size pixels. |
Coeffs (output_control)
|
integer-array -> integer
|
In case of gauss filter: coeffients of the ``positive''
half of the 1D impulse answer. |
Example
info_smooth(::'deriche2',0.5:Size,Coeffs) >
smooth__(Input:Smooth:'deriche2',7:) >
Result
If the parameter values are correct the operator
info_smooth returns the value TRUE. Otherwise an
exception is raised.
Possible Predecessors
read_image
Possible Successors
smooth__
See also
smooth__
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