Operator Reference

HALCON Operator Reference / Filters / Edges
ClassesClasses | | Operators

info_edgesT_info_edgesInfoEdgesInfoEdgesinfo_edges (Operator)

info_edgesT_info_edgesInfoEdgesInfoEdgesinfo_edges — Return the filter coefficients of a filter in edges_imageedges_imageEdgesImageEdgesImageedges_image.

Signature

info_edges( : : Filter, Mode, Alpha : Size, Coeffs)

Herror T_info_edges(const Htuple Filter, const Htuple Mode, const Htuple Alpha, Htuple* Size, Htuple* Coeffs)

void InfoEdges(const HTuple& Filter, const HTuple& Mode, const HTuple& Alpha, HTuple* Size, HTuple* Coeffs)

static Hlong HMisc::InfoEdges(const HString& Filter, const HString& Mode, double Alpha, HTuple* Coeffs)

static Hlong HMisc::InfoEdges(const char* Filter, const char* Mode, double Alpha, HTuple* Coeffs)

static Hlong HMisc::InfoEdges(const wchar_t* Filter, const wchar_t* Mode, double Alpha, HTuple* Coeffs)   ( Windows only)

static void HOperatorSet.InfoEdges(HTuple filter, HTuple mode, HTuple alpha, out HTuple size, out HTuple coeffs)

static int HMisc.InfoEdges(string filter, string mode, double alpha, out HTuple coeffs)

def info_edges(filter: str, mode: str, alpha: float) -> Tuple[int, Sequence[int]]

Description

info_edgesinfo_edgesInfoEdgesInfoEdgesinfo_edges returns the coefficients CoeffsCoeffsCoeffscoeffscoeffs and an estimate of the width SizeSizeSizesizesize of any of the filters used in edges_imageedges_imageEdgesImageEdgesImageedges_image. To do so, the corresponding continuous impulse responses of the filters are sampled until the first filter coefficient is smaller than five percent of the largest coefficient. AlphaAlphaAlphaalphaalpha is the filter parameter (see edges_imageedges_imageEdgesImageEdgesImageedges_image). Seven edge operators are supported (parameter FilterFilterFilterfilterfilter):

'deriche1'"deriche1""deriche1""deriche1""deriche1", 'lanser1'"lanser1""lanser1""lanser1""lanser1", 'deriche2'"deriche2""deriche2""deriche2""deriche2", 'lanser2'"lanser2""lanser2""lanser2""lanser2", 'shen'"shen""shen""shen""shen", 'mshen'"mshen""mshen""mshen""mshen" and 'canny'"canny""canny""canny""canny".

The parameter ModeModeModemodemode ('edge'"edge""edge""edge""edge"/'smooth'"smooth""smooth""smooth""smooth") is used to determine whether the corresponding edge or smoothing operator is to be sampled.

The Canny operator (which uses Gaussian smoothing) is implemented using conventional filter masks. Therefore, for the Canny filter, the coefficients CoeffsCoeffsCoeffscoeffscoeffs of the one-dimensional impulse responses are returned as . All other filters are implemented recursively; here, the CoeffsCoeffsCoeffscoeffscoeffs are coefficients of a corresponding non-recursive filter.

Attention

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.

Execution Information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).
  • Multithreading scope: global (may be called from any thread).
  • Processed without parallelization.

Parameters

FilterFilterFilterfilterfilter (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Name of the edge operator.

Default: 'lanser2' "lanser2" "lanser2" "lanser2" "lanser2"

List of values: 'canny'"canny""canny""canny""canny", 'deriche1'"deriche1""deriche1""deriche1""deriche1", 'deriche2'"deriche2""deriche2""deriche2""deriche2", 'lanser1'"lanser1""lanser1""lanser1""lanser1", 'lanser2'"lanser2""lanser2""lanser2""lanser2", 'mshen'"mshen""mshen""mshen""mshen", 'shen'"shen""shen""shen""shen"

ModeModeModemodemode (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

1D edge filter ('edge') or 1D smoothing filter ('smooth').

Default: 'edge' "edge" "edge" "edge" "edge"

List of values: 'edge'"edge""edge""edge""edge", 'smooth'"smooth""smooth""smooth""smooth"

AlphaAlphaAlphaalphaalpha (input_control)  real → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Filter parameter: small values result in strong smoothing, and thus less detail (opposite for 'canny').

Default: 0.5

Minimum increment: 0.01

Recommended increment: 0.1

Restriction: Alpha > 0.0

SizeSizeSizesizesize (output_control)  integer → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Filter width in pixels.

CoeffsCoeffsCoeffscoeffscoeffs (output_control)  integer-array → HTupleSequence[int]HTupleHtuple (integer) (int / long) (Hlong) (Hlong)

For Canny filters: Coefficients of the “positive” half of the 1D impulse response. All others: Coefficients of a corresponding non-recursive filter.

Example (HDevelop)

read_image(Image,'fabrik')
info_edges('lanser2','edge',0.5,Size,Coeffs)
edges_image(Image,Amp,Dir,'lanser2',0.5,'none',-1,-1)
hysteresis_threshold(Amp,Margin,20,30,30)

Example (C)

read_image(&Image,"fabrik");
info_edges("lanser2","edge",0.5,Size,Coeffs);
edges_image(Image,&Amp,&Dir,"lanser2",0.5,"none",-1,-1);
hysteresis_threshold(Amp,&Margin,20,30,30);

Example (HDevelop)

read_image(Image,'fabrik')
info_edges('lanser2','edge',0.5,Size,Coeffs)
edges_image(Image,Amp,Dir,'lanser2',0.5,'none',-1,-1)
hysteresis_threshold(Amp,Margin,20,30,30)

Example (HDevelop)

read_image(Image,'fabrik')
info_edges('lanser2','edge',0.5,Size,Coeffs)
edges_image(Image,Amp,Dir,'lanser2',0.5,'none',-1,-1)
hysteresis_threshold(Amp,Margin,20,30,30)

Result

info_edgesinfo_edgesInfoEdgesInfoEdgesinfo_edges returns 2 ( H_MSG_TRUE) if all parameters are correct. If the input is empty the behavior can be set via set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>). If necessary, an exception is raised.

Possible Successors

edges_imageedges_imageEdgesImageEdgesImageedges_image, thresholdthresholdThresholdThresholdthreshold, skeletonskeletonSkeletonSkeletonskeleton

See also

edges_imageedges_imageEdgesImageEdgesImageedges_image

Module

Foundation

ClassesClasses | | Operators