polar_trans_region_invpolar_trans_region_invpolar_trans_region_invPolarTransRegionInvPolarTransRegionInv (Operator)

Name

polar_trans_region_invpolar_trans_region_invpolar_trans_region_invPolarTransRegionInvPolarTransRegionInv — Transform a region in polar coordinates back to cartesian coordinates.

Signature

Description

polar_trans_region_invpolar_trans_region_invpolar_trans_region_invPolarTransRegionInvPolarTransRegionInv transforms the polar coordinate representation of a region, stored in PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion, back onto an annular arc in cartesian coordinates, described by the radii RadiusStartRadiusStartRadiusStartRadiusStartradiusStart and RadiusEndRadiusEndRadiusEndRadiusEndradiusEnd and the angles AngleStartAngleStartAngleStartAngleStartangleStart and AngleEndAngleEndAngleEndAngleEndangleEnd with the center point located at (RowRowRowRowrow, ColumnColumnColumnColumncolumn). All of these values can be chosen as real numbers. In addition, the dimensions of the virtual image containing the region PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion must be given in WidthInWidthInWidthInWidthInwidthIn and HeightInHeightInHeightInHeightInheightIn. WidthInWidthInWidthInWidthInwidthIn-1 is the column coordinate corresponding to AngleEndAngleEndAngleEndAngleEndangleEnd and HeightInHeightInHeightInHeightInheightIn-1 is the row coordinate corresponding to RadiusEndRadiusEndRadiusEndRadiusEndradiusEnd. AngleStartAngleStartAngleStartAngleStartangleStart and RadiusStartRadiusStartRadiusStartRadiusStartradiusStart correspond to column and row coordinate 0. Furthermore, the dimensions WidthWidthWidthWidthwidth and HeightHeightHeightHeightheight of the virtual output image containing the transformed region XYTransRegionXYTransRegionXYTransRegionXYTransRegionXYTransRegion are required.

The angles and radii are inclusive, which means that the row coordinate 0 in PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion will be mapped onto a a circle with a distance of RadiusStartRadiusStartRadiusStartRadiusStartradiusStart pixels from the specified center and the row with the coordinate HeightInHeightInHeightInHeightInheightIn-1 will be mapped onto a circle of radius RadiusEndRadiusEndRadiusEndRadiusEndradiusEnd. This applies to AngleStartAngleStartAngleStartAngleStartangleStart, AngleEndAngleEndAngleEndAngleEndangleEnd, and WidthInWidthInWidthInWidthInwidthIn in an analogous way. If the width of the input region PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion corresponds to an angle interval greater than 2pi, the region is cropped such that length of this interval is 2pi.

The parameter InterpolationInterpolationInterpolationInterpolationinterpolation is used to select the interpolation method 'bilinear'"bilinear""bilinear""bilinear""bilinear" or 'nearest_neighbor'"nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor". Setting InterpolationInterpolationInterpolationInterpolationinterpolation to 'bilinear'"bilinear""bilinear""bilinear""bilinear" leads to smoother region boundaries, especially if regions are enlarged. However, the runtime increases significantly.

polar_trans_region_invpolar_trans_region_invpolar_trans_region_invPolarTransRegionInvPolarTransRegionInv is the inverse function of polar_trans_regionpolar_trans_regionpolar_trans_regionPolarTransRegionPolarTransRegion.

The call sequence:

polar_trans_region(Region, PolarRegion, Row, Column, rad(360), 0, 0,
                       Radius, Width, Height, 'nearest_neighbor')
polar_trans_region_inv(PolarRegion, XYTransRegion, Row, Column, rad(360), 0,
                       0, Radius, Width, Height, Width, Height,
                       'nearest_neighbor')

returns the region Region, restricted to the circle around (Row, Column) with radius Radius, as its output region XYTransRegion.

If more than one region is passed in PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion, their cartesian transformations are computed individually and stored as a tuple in XYTransRegionXYTransRegionXYTransRegionXYTransRegionXYTransRegion. Please note that the indices of an input region and its transformation only correspond if the system variable 'store_empty_regions'"store_empty_regions""store_empty_regions""store_empty_regions""store_empty_regions" is set to 'false'"false""false""false""false" (see set_systemset_systemset_systemSetSystemSetSystem). Otherwise empty output regions are discarded and the length of the input tuple PolarRegionPolarRegionPolarRegionPolarRegionpolarRegion is most likely not equal to the length of the output tuple XYTransRegionXYTransRegionXYTransRegionXYTransRegionXYTransRegion.

Attention

If WidthWidthWidthWidthwidth or HeightHeightHeightHeightheight are chosen greater than the dimensions of the current image, the system variable 'clip_region'"clip_region""clip_region""clip_region""clip_region" should be set to 'false'"false""false""false""false" (see set_systemset_systemset_systemSetSystemSetSystem). Otherwise, an output region that does not lie within the dimensions of the current image can produce an error message.

Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Automatically parallelized on tuple level.
• Automatically parallelized on internal data level.

Parameters

See also

polar_trans_imagepolar_trans_imagepolar_trans_imagePolarTransImagePolarTransImage, polar_trans_image_extpolar_trans_image_extpolar_trans_image_extPolarTransImageExtPolarTransImageExt, polar_trans_image_invpolar_trans_image_invpolar_trans_image_invPolarTransImageInvPolarTransImageInv, polar_trans_regionpolar_trans_regionpolar_trans_regionPolarTransRegionPolarTransRegion, polar_trans_contour_xldpolar_trans_contour_xldpolar_trans_contour_xldPolarTransContourXldPolarTransContourXld, polar_trans_contour_xld_invpolar_trans_contour_xld_invpolar_trans_contour_xld_invPolarTransContourXldInvPolarTransContourXldInv

Module

Foundation