Operator Reference
gen_cube_map_mosaic (Operator)
gen_cube_map_mosaic — Create 6 cube map images of a spherical mosaic.
Signature
gen_cube_map_mosaic(Images : Front, Rear, Left, Right, Top, Bottom : CameraMatrices, RotationMatrices, CubeMapDimension, StackingOrder, Interpolation : )
Description
gen_cube_map_mosaic creates 6 cube map images of a spherical
mosaic Front, Left, Rear, Right,
Top and Bottom from the input images passed in
Images. The pose of the images in space, which is used to
compute the position of the images with respect to the surface of
the sphere, can be determined with
stationary_camera_self_calibration. The camera and rotation
matrices computed with stationary_camera_self_calibration
can be used in CameraMatrices and
RotationMatrices. A spherical mosaic can only be created
from images that were taken with a stationary camera (see
stationary_camera_self_calibration).
The width and height of the output cube map images can be selected by
setting the parameter CubeMapDimension. The value represents
the width and height in pixels.
The mode in which the images are added to the mosaic is given by
StackingOrder. For StackingOrder =
'voronoi', the points in the mosaic image are determined
from the Voronoi cell of the respective input image. This means
that the gray values are taken from the points of the input image to
whose center the pixel in the mosaic image has the smallest distance
on the sphere. This mode has the advantage that vignetting and
uncorrected radial distortions are less noticeable in the mosaic
image because they typically are symmetric with respect to the image
center. Alternatively, with the choice of parameters described
in the following, a mode can be selected that has the same
effect as if the images were painted successively into the mosaic
image. Here, the order in which the images are added to the mosaic
image is important. Therefore, an array of integer values can be
passed in StackingOrder. The first index in this array
will end up at the bottom of the image stack while the last one will
be on top. If 'default' is given instead of an array of
integers, the canonical order (images in the order used in
Images) will be used. Hence, if neither 'voronoi'
nor 'default' are used, StackingOrder must contain
a permutation of the numbers 1,...,n, where n is the number of
images passed in Images. It should be noted that the mode
'voronoi' cannot always be used. For example, at least
two images must be passed to use this mode. Furthermore, for very
special configurations of the positions of the image centers on the
sphere, the Voronoi cells cannot be determined uniquely. With
StackingOrder = 'blend', an additional mode is
available, which blends the images of the mosaic smoothly. This way seams
between the images become less apparent. The seam lines between the images
are the same as in 'voronoi'. This mode leads to visually more
appealing images, but requires significantly more resources. If the
mode 'voronoi' or 'blend' cannot be used for whatever
reason the mode is switched internally to 'default' automatically.
The parameter Interpolation selects the desired interpolation mode
for creating the cube maps. 'bilinear' and 'bicubic'
interpolation is available for all modes of StackingOrder.
'nearest_neighbor' is only available if StackingOrder is
set to 'default' or 'voronoi'.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Parameters
Images (input_object) (multichannel-)image-array → object (byte / uint2 / real)
Input images.
Front (output_object) (multichannel-)image → object (byte / uint2 / real)
Front cube map.
Rear (output_object) (multichannel-)image → object (byte / uint2 / real)
Rear cube map.
Left (output_object) (multichannel-)image → object (byte / uint2 / real)
Left cube map.
Right (output_object) (multichannel-)image → object (byte / uint2 / real)
Right cube map.
Top (output_object) (multichannel-)image → object (byte / uint2 / real)
Top cube map.
Bottom (output_object) (multichannel-)image → object (byte / uint2 / real)
Bottom cube map.
CameraMatrices (input_control) hom_mat2d-array → (real)
(Array of) 3x3 projective camera matrices that determine the internal camera parameters.
RotationMatrices (input_control) hom_mat2d-array → (real)
Array of 3x3 transformation matrices that determine rotation of the camera in the respective image.
CubeMapDimension (input_control) number → (integer)
Width and height of the resulting cube maps.
Default: 1000
Restriction:
CubeMapDimension >= 0
StackingOrder (input_control) string(-array) → (string / integer)
Mode of adding the images to the mosaic image.
Default: 'voronoi'
Suggested values: 'blend', 'voronoi', 'default'
Interpolation (input_control) string → (string)
Mode of image interpolation.
Default: 'bilinear'
Suggested values: 'nearest_neighbor', 'bilinear', 'bicubic'
Example (HDevelop)
* For the input data to stationary_camera_self_calibration, please
* refer to the example for stationary_camera_self_calibration.
stationary_camera_self_calibration (4, 640, 480, 1, From, To, \
HomMatrices2D, Rows1, Cols1, \
Rows2, Cols2, NumMatches, \
'gold_standard', \
['focus','principal_point'], \
'true', CameraMatrix, Kappa, \
RotationMatrices, X, Y, Z, Error)
gen_cube_map_mosaic (Images, Front, Left, Rear, Right, Top, Bottom, \
CameraMatrix, RotationMatrices, 1000, 'default', \
'bicubic')
* Alternatively, if kappa should be determined, the following calls
* can be made:
stationary_camera_self_calibration (4, 640, 480, 1, From, To, \
HomMatrices2D, Rows1, Cols1, \
Rows2, Cols2, NumMatches, \
'gold_standard', \
['focus','principal_point','kappa'], \
'true', CameraMatrix, Kappa, \
RotationMatrices, X, Y, Z, Error)
cam_mat_to_cam_par (CameraMatrix, Kappa, 640, 480, CamParam)
change_radial_distortion_cam_par ('fixed', CamParam, 0, CamParOut)
gen_radial_distortion_map (Map, CamParam, CamParOut, 'bilinear')
map_image (Images, Map, ImagesRect)
gen_cube_map_mosaic (Images, Front, Left, Rear, Right, Top, Bottom, \
CameraMatrix, RotationMatrices, 1000, 'default', \
'bicubic')
Result
If the parameters are valid, the operator
gen_cube_map_mosaic returns the value 2 (
H_MSG_TRUE)
. If necessary
an exception is raised.
Possible Predecessors
stationary_camera_self_calibration
Alternatives
gen_spherical_mosaic,
gen_projective_mosaic
References
Lourdes Agapito, E. Hayman, I. Reid: “Self-Calibration of Rotating
and Zooming Cameras”; International Journal of Computer Vision;
vol. 45, no. 2; pp. 107--127; 2001.
Olivier Faugeras, Quang-Tuan Luong: “The Geometry of Multiple
Images: The Laws That Govern the Formation of Multiple Images of a
Scene and Some of Their Applications”; MIT Press, Cambridge, MA;
2001.
Module
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