HALCON Reference Manual 10.0.2

approx_chain_simpleT_approx_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple (Operator)

Name

approx_chain_simpleT_approx_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple — Approximate a contour by arcs and lines.

Signature

approx_chain_simple( : : Row, Column : ArcCenterRow, ArcCenterCol, ArcAngle, ArcBeginRow, ArcBeginCol, LineBeginRow, LineBeginCol, LineEndRow, LineEndCol, Order)

Description

The contour of a curve is approximated by a sequence of lines and arcs.

The result of the procedure is returned separately as arcs and lines. If one is interested in the sequence of the segments the individual resulting elements can be read successively from the resulting tuples. The sequence can be taken from the return parameter order (0: next element is next line segment, 1: next element is next arc segment).

The operator approx_chain_simpleapprox_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple behaves similarly as approx_chainapprox_chainapprox_chainApproxChainApproxChain except that in the case of approx_chain_simpleapprox_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple the missing parameters are internally allocated as follows: MinWidthCoord = 1.0, MaxWidthCoord = 3.0, ThreshStart = 0.5, ThreshEnd = 0.9, ThreshStep = 0.3, MinWidthSmooth = 1.0, MaxWidthSmooth = 3.0, MinWidthCurve = 2, MaxWidthCurve = 9, Weight1 = 1.0, Weight2 = 1.0, Weight3 = 1.0.

Parallelization

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

Parameters

RowRowRowRowrow (input_control) point.y → (integer)

Row of the contour.

Default value: 32

ColumnColumnColumnColumncolumn (input_control) point.x → (integer)

Column of the contour.

Default value: 32

ArcCenterRowArcCenterRowArcCenterRowArcCenterRowarcCenterRow (output_control) arc.center.y-array → (integer)

Row of the center of an arc.

ArcCenterColArcCenterColArcCenterColArcCenterColarcCenterCol (output_control) arc.center.x-array → (integer)

Column of the center of an arc.

ArcAngleArcAngleArcAngleArcAnglearcAngle (output_control) arc.angle.rad-array → (real)

Angle of an arc.

ArcBeginRowArcBeginRowArcBeginRowArcBeginRowarcBeginRow (output_control) arc.begin.y-array → (integer)

Row of the starting point of an arc.

ArcBeginColArcBeginColArcBeginColArcBeginColarcBeginCol (output_control) arc.begin.x-array → (integer)

Column of the starting point of an arc.

LineBeginRowLineBeginRowLineBeginRowLineBeginRowlineBeginRow (output_control) line.begin.y-array → (integer)

Row of the starting point of a line segment.

LineBeginColLineBeginColLineBeginColLineBeginCollineBeginCol (output_control) line.begin.x-array → (integer)

Column of the starting point of a line segment.

LineEndRowLineEndRowLineEndRowLineEndRowlineEndRow (output_control) line.end.y-array → (integer)

Row of the ending point of a line segment.

LineEndColLineEndColLineEndColLineEndCollineEndCol (output_control) line.end.x-array → (integer)

Column of the ending point of a line segment.

OrderOrderOrderOrderorder (output_control) integer-array → (integer)

Sequence of line (value 0) and arc segments (value 1).

Example (C)

/* read edge image */
read_image(&Image,"fig1_kan");
/* construct edge region */
hysteresis_threshold(Image,&RK1,64,255,40,1);
connection(RK1,&Rand);
/* fetch chain code */
T_get_region_contour(Rand,&Rows,&Columns);
firstline = get_i(Tline,0);
firstcol = get_i(Tcol,0);
/* approximation with lines and circular arcs */
T_approx_chain_simple(Rows,Columns,
                &Bzl,&Bzc,&Br,&Bwl,&Bwc,&Ll0,&Lc0,&Ll1,&Lc1,&order);
nob = length_tuple(Bzl);
nol = length_tuple(Ll0);
/* draw lines and arcs */
set_i(WindowHandleTuple,WindowHandle,0) ;
set_line_width(WindowHandle,4);
if (nob>0) T_disp_arc(Bzl,Bzc,Br,Bwl,Bwc);
set_line_width(WindowHandle,1);
if (nol>0) T_disp_line(WindowHandleTuple,Ll0,Lc0,Ll1,Lc1);

Result

The operator approx_chain_simpleapprox_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple returns the value 2 (H_MSG_TRUE) if the parameters are correct. Otherwise an exception is raised.

Possible Predecessors

sobel_ampsobel_ampsobel_ampSobelAmpSobelAmp, edges_imageedges_imageedges_imageEdgesImageEdgesImage, get_region_contourget_region_contourget_region_contourGetRegionContourGetRegionContour, thresholdthresholdthresholdThresholdThreshold, hysteresis_thresholdhysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThreshold

Operators