info_smooth — Information on smoothing filter
info_smooth returns an estimation of the
width of the smoothing filters used in routine
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
Currently four filters are supported (parameter
'deriche1', 'deriche2', 'shen' and '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 ) are returned
Coeffs in addition to the filter size.
For an explanation of the concept of smoothing filters see the introduction of chapter Filters / Smoothing.
Note that filter operators may return unexpected results if an image with a reduced domain is used as input. Please refer to the chapter Filters.
Name of required filter.
Default value: 'deriche2'
List of values: 'deriche1', 'deriche2', 'gauss', 'shen'
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
Typical range of values:
Minimum increment: 0.01
Recommended increment: 0.1
Alpha > 0.0
Width of filter is approx. size x size pixels.
In case of gauss filter: coefficients of the “positive” half of the 1D impulse answer.
If the parameter values are correct the operator
info_smooth returns the value 2 (H_MSG_TRUE). Otherwise an
exception is raised.