gen_image_to_world_plane_mapT_gen_image_to_world_plane_mapGenImageToWorldPlaneMapGenImageToWorldPlaneMapgen_image_to_world_plane_map — Generate a projection map that describes the mapping between the image
plane and the plane z=0 of a world coordinate system.
gen_image_to_world_plane_mapgen_image_to_world_plane_mapGenImageToWorldPlaneMapGenImageToWorldPlaneMapGenImageToWorldPlaneMapgen_image_to_world_plane_map generates a projection map MapMapMapMapmapmap,
which describes the mapping between the image plane and the plane z=0
(plane of measurements) in a world coordinate system. This map can be used
to rectify an image with the operator map_imagemap_imageMapImageMapImageMapImagemap_image. The rectified
image shows neither radial nor perspective distortions; it corresponds to
an image acquired by a distortion-free camera that looks perpendicularly
onto the plane of measurements. The world coordinate system (wcs)
is chosen by passing its 3D pose relative to the camera coordinate system
(ccs) in
WorldPoseWorldPoseWorldPoseWorldPoseworldPoseworld_pose. Thus the pose is expected in the form
(see Transformations / Poses
and “Solution Guide III-C - 3D Vision”).
In CameraParamCameraParamCameraParamCameraParamcameraParamcamera_param you must pass the internal camera
parameters (see Calibration for the sequence of the
parameters and the underlying camera model).
The parameter ScaleScaleScaleScalescalescale can be used to specify the size of a pixel in the
transformed image. There are two ways to use this parameter:
Scale pixels to metric units:
Scale the image such that one pixel in the transformed image corresponds
to a metric unit, e.g., setting 'mm'"mm""mm""mm""mm""mm" determines that a pixel in the
transformed image corresponds to the area 1mm x 1mm in the
plane of measurements. For this, the original unit needs to be meters.
This is the case if you use a standard calibration plate.
List of values:'m'"m""m""m""m""m", 'cm'"cm""cm""cm""cm""cm", 'mm'"mm""mm""mm""mm""mm",
'microns'"microns""microns""microns""microns""microns", 'um'"um""um""um""um""um".
Default:'m'"m""m""m""m""m".
Control scaling manually:
Scale the image by giving a number that determines the ratio of
original unit length / desired number of pixels.
E.g., if your original unit is meters and you want
every pixel of your transformed image to represent 3mm x 3mm
of the measuring plane, your scale is calculated
.
If you want to perform a task like shape-based matching on your
transformed image, it is useful to scale the image such that its content
appears in a size similar to the original image.
The mapping function is stored in the output image MapMapMapMapmapmap.
MapMapMapMapmapmap has the same size as the resulting images after the mapping.
MapTypeMapTypeMapTypeMapTypemapTypemap_type is used to specify the type of the output MapMapMapMapmapmap.
If 'nearest_neighbor'"nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor" is chosen, MapMapMapMapmapmap consists of one image
containing one channel, in which for each pixel of the resulting image the
linearized coordinate of the pixel of the input image is stored that is the
nearest neighbor to the transformed coordinates. If 'bilinear'"bilinear""bilinear""bilinear""bilinear""bilinear"
interpolation is chosen, MapMapMapMapmapmap consists of one image containing five
channels. In the first channel for each pixel in the resulting image the
linearized coordinates of the pixel in the input image is stored that is in
the upper left position relative to the transformed coordinates.
The four other channels contain the weights of the four neighboring pixels
of the transformed coordinates which are used for the bilinear
interpolation, in the following order:
2
3
4
5
The second channel, for example, contains the weights of the pixels that
lie to the upper left relative to the transformed coordinates.
If 'coord_map_sub_pix'"coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix" is chosen, MapMapMapMapmapmap consists of
one vector field image of the semantic type 'vector_field_absolute', in
which for each pixel of the resulting image the subpixel precise
coordinates in the input image are stored.
List of values:
'bilinear'"bilinear""bilinear""bilinear""bilinear""bilinear", 'coord_map_sub_pix'"coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix""coord_map_sub_pix", 'nearest_neighbor'"nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor"
Example (HDevelop)
* Calibrate camera.
calibrate_cameras (CalibDataID, Error)
* Obtain camera parameters.
get_calib_data (CalibDataID, 'camera', 0, 'params', CamParam)
* Example values, if no calibration data is available:
CamParam := ['area_scan_division', 0.0087, -1859, 8.65e-006, 8.6e-006, \
362.5, 291.6, 768, 576]
* Get reference pose (pose 4 of calibration object 0).
get_calib_data (CalibDataID, 'calib_obj_pose',\
[0,4], 'pose', Pose)
* Example values, if no calibration data is available:
Pose := [-0.11, -0.21, 2.51, 352.73, 346.73, 336.48, 0]
* Compensate thickness of plate.
set_origin_pose (Pose, -1.125, -1.0, 0, PoseNewOrigin)
* Transform the image into the world plane.
read_image (Image, 'calib/calib-3d-coord-04')
gen_image_to_world_plane_map (MapSingle, CamParam, PoseNewOrigin,\
CamParam[6], CamParam[7], 900, 800, 0.0025, 'bilinear')
map_image (Image, MapSingle, ImageMapped)
Result
gen_image_to_world_plane_mapgen_image_to_world_plane_mapGenImageToWorldPlaneMapGenImageToWorldPlaneMapGenImageToWorldPlaneMapgen_image_to_world_plane_map returns 2 (
H_MSG_TRUE)
if all parameter values
are correct. If necessary, an exception is raised.