find_rectification_gridfind_rectification_gridFindRectificationGridFindRectificationGrid (Operator)


find_rectification_gridfind_rectification_gridFindRectificationGridFindRectificationGrid — Segment the rectification grid region in the image.


find_rectification_grid(Image : GridRegion : MinContrast, Radius : )

Herror find_rectification_grid(const Hobject Image, Hobject* GridRegion, double MinContrast, double Radius)

Herror T_find_rectification_grid(const Hobject Image, Hobject* GridRegion, const Htuple MinContrast, const Htuple Radius)

void FindRectificationGrid(const HObject& Image, HObject* GridRegion, const HTuple& MinContrast, const HTuple& Radius)

HRegion HImage::FindRectificationGrid(const HTuple& MinContrast, const HTuple& Radius) const

HRegion HImage::FindRectificationGrid(double MinContrast, double Radius) const

static void HOperatorSet.FindRectificationGrid(HObject image, out HObject gridRegion, HTuple minContrast, HTuple radius)

HRegion HImage.FindRectificationGrid(HTuple minContrast, HTuple radius)

HRegion HImage.FindRectificationGrid(double minContrast, double radius)


find_rectification_gridfind_rectification_gridFindRectificationGridFindRectificationGridFindRectificationGrid searches in the image ImageImageImageImageimage for image parts that contain the rectification grid and returns them in the region GridRegionGridRegionGridRegionGridRegiongridRegion. To do so, essentially image areas with a contrast of at least MinContrastMinContrastMinContrastMinContrastminContrast are extracted and the holes in these areas are filled up. Then, an opening with the radius RadiusRadiusRadiusRadiusradius is applied to these areas to eliminate smaller areas of high contrast.

During grid-rectification, a careful reduction of the input region to those image parts that actually contain the rectification grid is useful for two purposes: First, the computing time can be reduced and secondly, saddle_points_sub_pixsaddle_points_sub_pixSaddlePointsSubPixSaddlePointsSubPixSaddlePointsSubPix and connect_grid_pointsconnect_grid_pointsConnectGridPointsConnectGridPointsConnectGridPoints can be prevented from detecting false grid points and connecting lines.

Execution Information


ImageImageImageImageimage (input_object)  singlechannelimage objectHImageHImageHobject (byte / uint2)

Input image.

GridRegionGridRegionGridRegionGridRegiongridRegion (output_object)  region objectHRegionHRegionHobject *

Output region containing the rectification grid.

MinContrastMinContrastMinContrastMinContrastminContrast (input_control)  number HTupleHTupleHtuple (real / integer) (double / int / long) (double / Hlong) (double / Hlong)

Minimum contrast.

Default value: 8.0

Suggested values: 2.0, 4.0, 8.0, 16.0, 32.0

Restriction: MinContrast >= 0

RadiusRadiusRadiusRadiusradius (input_control)  real HTupleHTupleHtuple (real / integer) (double / int / long) (double / Hlong) (double / Hlong)

Radius of the circular structuring element.

Default value: 7.5

Suggested values: 1.5, 2.5, 3.5, 4.5, 5.5, 7.5, 9.5, 12.5, 15.5, 19.5, 25.5, 33.5, 45.5, 60.5, 110.5

Restriction: Radius >= 0.5

Example (HDevelop)

find_rectification_grid (Image, GridRegion, 8, 10)
dilation_circle (GridRegion, GridRegionDilated, 5.5)
reduce_domain (Image, GridRegionDilated, ImageReduced)
saddle_points_sub_pix (ImageReduced, 'facet', 1.5, 5, Row, Column)
connect_grid_points (ImageReduced, ConnectingLines, Row, Column, 1.1, 5.5)
gen_grid_rectification_map (ImageReduced, ConnectingLines, Map, Meshes, 20, \
                            'auto', Row, Column, 'bilinear')
map_image (Image, Map, ImageMapped)


find_rectification_gridfind_rectification_gridFindRectificationGridFindRectificationGridFindRectificationGrid returns 2 (H_MSG_TRUE) if all parameter values are correct. If necessary, an exception is raised.

Possible Successors

dilation_circledilation_circleDilationCircleDilationCircleDilationCircle, reduce_domainreduce_domainReduceDomainReduceDomainReduceDomain