ifanbeam() - Image Processing

I = ifanbeam(F,D) reconstructs
the image I from projection data in the two-dimensional array F.
Each column of F contains fan-beam projection data
at one rotation angle. ifanbeam assumes that the
center of rotation is the center point of the projections, which is
defined as ceil(size(F,1)/2).The fan-beam spread angles are assumed to be the same increments
as the input rotation angles split equally on either side of zero.
The input rotation angles are assumed to be stepped in equal increments
to cover [0:359] degrees.D is the distance from the fan-beam vertex
to the center of rotation.I = ifanbeam(...,param1,val1,param2,val2,...) specifies
parameters that control various aspects of the ifanbeam reconstruction,
described in the following table. Parameter names can be abbreviated,
and case does not matter. Default values are in braces ({}).ParameterDescription
'FanCoverage'String specifying the range through which the beams are
rotated.{'cycle'} — Rotate
through the full range [0,360).'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. See fanbeam for
details. 
'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.
'Filter'String specifying the name of a filter. See iradon for
details.
'FrequencyScaling'Scalar in the range (0,1] that modifies the filter by
rescaling its frequency axis. See iradon for
details.
'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
'OutputSize'Positive scalar specifying the number of rows and columns
in the reconstructed image.If 'OutputSize' is
not specified, ifanbeam determines the size automatically.If
you specify 'OutputSize', ifanbeam reconstructs
a smaller or larger portion of the image, but does not change the
scaling of the data.Note:  


 If the projections were calculated with the fanbeam function,
the reconstructed image might not be the same size as the original
image.
[I,H] = ifanbeam(...) returns
the frequency response of the filter in the vector H.

Syntax

I = ifanbeam(F,D)I = ifanbeam(...,param1,val1,param2,val2,...)[I,H] = ifanbeam(...)

Example

ph = phantom(128);
d = 100;
F = fanbeam(ph,d);
I = ifanbeam(F,d);
imshow(ph), figure, imshow(I);

Output / Return Value

Limitations

Alternatives / See Also

Reference