CylindricalDetector¶

class odl.tomo.geometry.detector.CylindricalDetector(partition, axes, radius, check_bounds=True)[source]¶

Bases: Detector

A 2D detector on a cylindrical surface in 3D space.

The cylindrical surface that corresponds to the partition is rotated to be aligned with given axes and shifted to cross the origin. Note that the partition angle increases in the clockwise direction, by analogy to flat detectors.

Attributes:

axes: Fixed array of unit vectors with which the detector is aligned.
check_bounds: If True, methods computing vectors check input arguments.
grid: Sampling grid of the parameters.
ndim: Number of dimensions of the parameters (= surface dimension).
params: Surface parameter set of this detector.
partition: Partition of the detector parameter set into subsets.
radius: Curvature radius of the detector.
rotation_matrix: Rotation matrix that is used to align the detector with a given axis.
shape: Number of subsets (pixels) of the detector per axis.
size: Total number of pixels.
space_ndim: Number of dimensions of the embedding space.
translation: A vector used to shift the detector towards the origin.

Methods

`surface`(param)	Return the detector surface point corresponding to `param`.
`surface_deriv`(param)	Return the surface derivative at `param`.
`surface_measure`(param)	Density function of the surface measure.
`surface_normal`(param)	Unit vector perpendicular to the detector surface at `param`.

__init__(partition, axes, radius, check_bounds=True)[source]¶

Initialize a new instance.

Parameters:

partition2-dim. RectPartition: Partition of the parameter interval, corresponding to the angular partition and height partition.
axessequence of array-like: Fixed pair of of unit vectors with which the detector is aligned. The vectors must have shape (3,) and be perpendicular.
radiusnonnegative float: Radius of the cylinder.
check_boundsbool, optional: If True, methods computing vectors check input arguments. Checks are vectorized and add only a small overhead.

Examples

Initialize a detector with height 8 and circle radius 2 extending to 90 degrees on both sides of the origin (a half cylinder).

>>> part = odl.uniform_partition(
...     [-np.pi / 2, -4], [np.pi / 2, 4], [10, 8])
>>> det = CylindricalDetector(
...     part, axes=[(1, 0, 0), (0, 0, 1)], radius=2)
>>> det.axes
array([[ 1.,  0.,  0.],
       [ 0.,  0.,  1.]])
>>> det.radius
2.0
>>> np.allclose(det.surface_normal([0, 0]), [ 0, -1,  0])
True