fan2para() - Image Processing

P = fan2para(F,D) converts
the fan-beam data F to the parallel-beam data P. D is
the distance in pixels from the fan-beam vertex to the center of rotation
that was used to obtain the projections.P = fan2para(..., param1, val1, param2,
val2,...) specifies parameters that control various aspects
of the fan2para conversion, listed in the following
table. Parameter names can be abbreviated, and case does not matter.ParameterDescription
'FanCoverage'String specifying the range through which the beams are
rotated.'cycle' — Rotate through
 the full range [0,360). This is
the default.'minimal' — Rotate
the minimum range necessary to represent the object.
'FanRotationIncrement'Positive real scalar specifying the increment of the
rotation angle of the fan-beam projections, measured in degrees. Default
value is 1.
'FanSensorGeometry'String specifying how sensors are positioned.'arc' —
Sensors are spaced equally along a circular arc at distance D from
the center of rotation. Default value is 'arc''line' —
Sensors are spaced equally along a line, the closest point of which
is distance D from the center of rotation. See fanbeam for
details.
'FanSensorSpacing'Positive real scalar specifying the spacing of the fan-beam
sensors. Interpretation of the value depends on the setting of 'FanSensorGeometry'.If 'FanSensorGeometry' is
set to 'arc' (the default), the value defines the
angular spacing in degrees. Default value is 1.If 'FanSensorGeometry' is 'line',
the value specifies the linear spacing. Default value is 1.  See fanbeam for
details.Note:  


This linear spacing is measured on the x' axis.
The x' axis for each column, col,
of F is oriented at fan_rotation_angles(col) degrees
counterclockwise from the x-axis. The origin of both axes is the center
pixel of the image.
'Interpolation'Text string specifying the type of interpolation used
between the parallel-beam and fan-beam data.'nearest' —
Nearest-neighbor{'linear'} —
Linear'spline' — Piecewise
cubic spline'pchip' — Piecewise
cubic Hermite (PCHIP)'v5cubic' —
The cubic interpolation from MATLAB® 5
'ParallelCoverage'Text string specifying the range of rotation.'cycle' —
Parallel data covers 360 degrees{'halfcycle'} —
Parallel data covers 180 degrees
'ParallelRotationIncrement'Positive real scalar specifying the parallel-beam rotation
angle increment, measured in degrees. Parallel beam angles are calculated
to cover [0,180) degrees with increment PAR_ROT_INC,
where PAR_ROT_INC is the value of 'ParallelRotationIncrement'. 180/PAR_ROT_INC must be an integer.If 'ParallelRotationIncrement' is
not specified, the increment is assumed to be the same as the increment
of the fan-beam rotation angles.
 'ParallelSensorSpacing'Positive real scalar specifying the spacing of the parallel-beam
sensors in pixels. The range of sensor locations is implied by the
range of fan angles and is given by[D*sin(min(FAN_ANGLES)),...
 D*sin(max(FAN_ANGLES))]If 'ParallelSensorSpacing' is
not specified, the spacing is assumed to be uniform and is set to
the minimum spacing implied by the fan angles and sampled over the
range implied by the fan angles.
[P ,parallel_locations, parallel_rotation_angles]
= fan2para(...) returns the parallel-beam sensor locations
in parallel_locations and rotation angles in parallel_rotation_angles.

Syntax

P = fan2para(F,D)P = fan2para(..., param1, val1, param2,
val2,...)[P ,parallel_locations, parallel_rotation_angles]
= fan2para(...)

Example

[D*sin(min(FAN_ANGLES)),...
 D*sin(max(FAN_ANGLES))]

Output / Return Value

Limitations

Alternatives / See Also

Reference