get_region_chainT_get_region_chainget_region_chainGetRegionChainGetRegionChain (Operator)

Name

get_region_chainT_get_region_chainget_region_chainGetRegionChainGetRegionChain — Contour of an object as chain code.

Signature

Description

The operator get_region_chainget_region_chainget_region_chainGetRegionChainGetRegionChain returns the contour of a region. A contour is a series of pixels describing the outline of the region. The contour “lies on” the region. It starts at the smallest line number; in that line at the pixel with the largest column index. The rotation occurs clockwise. Holes of the region are ignored. The direction code (chain code) is defined as follows:

                        3       2       1
                        4       *       0
                        5       6       7

The operator get_region_chainget_region_chainget_region_chainGetRegionChainGetRegionChain returns the code in the form of a tuple. In case of an empty region the parameters RowRowRowRowrow and ColumnColumnColumnColumncolumn are zero and ChainChainChainChainchain is the empty tuple.

Attention

Holes of the region are ignored. Only one region may be passed, and it must have exactly one connection component.

Parallelization

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

Parameters

Result

The operator get_region_chainget_region_chainget_region_chainGetRegionChainGetRegionChain normally returns the value 2 (H_MSG_TRUE). If more than one connection component is passed an exception is raised. The behavior in case of empty input (no input regions available) is set via the operator set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). The behavior in case of empty region (the region is the empty set) is set via the operator set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

sobel_ampsobel_ampsobel_ampSobelAmpSobelAmp, thresholdthresholdthresholdThresholdThreshold, skeletonskeletonskeletonSkeletonSkeleton, edges_imageedges_imageedges_imageEdgesImageEdgesImage, gen_rectangle1gen_rectangle1gen_rectangle1GenRectangle1GenRectangle1, gen_circlegen_circlegen_circleGenCircleGenCircle

Possible Successors

approx_chainapprox_chainapprox_chainApproxChainApproxChain, approx_chain_simpleapprox_chain_simpleapprox_chain_simpleApproxChainSimpleApproxChainSimple

See also

copy_objcopy_objcopy_objCopyObjCopyObj, get_region_contourget_region_contourget_region_contourGetRegionContourGetRegionContour, get_region_polygonget_region_polygonget_region_polygonGetRegionPolygonGetRegionPolygon

Module

Foundation