pjrec

Reconstructs the interior of an object from a projection file.

Usage

pjrec projection-filename image-filename image-cols image-rows [options...]

Options

Parameter Options

- -filter Selects which filter to apply to each projection. To properly reconstruct an image, this filter should consist of the the absolute value of distance from zero frequency optionally multiplied by a smoothing filter. The optimal filters to use are:

abs_bandlimit
abs_cosine
abs_hamming
abs_hanning

- -filter-parameter Sets the alpha level for Hamming window. This parameter adjusts the smoothing of the Hamming filter and can range from 0 to 1. At a setting of 1, the Hamming filter is the same as the bandlimit filter. At a setting of 0.54, the Hamming filter is the same as the Hanning window.

- -filter-method Selects the filtering method. For large numbers of detectors, rfftw is optimal. For smaller numbers of detectors, convolution might be a bit faster.

convolution
fourier - Uses simple Fourier transform.
fourier-table - Optimizes Fourier transform by precalculating trigometric functions.
fftw - Uses complex-valued Fourier transform with the fftw library.
rfftw - Uses optimized real/half-complex Fourier transform.

- -filter-generation Selects the filter generation. With convolution, direct is the proper method to select. With any of the frequency methods, inverse-fourier is the best method.

direct
inverse-fourier

- -interpolation Interpolation technique during backprojection. cubic has optimal quality when the data is smooth. Smooth data is obtained by taking many projections and/or using a smoothing filter. In the absence of smooth data, linear gives better results and is many times faster than cubic interpolation.

nearest - No interpolation, selects nearest point.
linear - Uses fast straight line interpolation.
cubic - Uses cubic interpolating polynomial.

- -backprojection Selects the backprojection technique. A setting of idiff is optimal.

trig - Use trigometric functions at each image point.
table - Use precalculated trigometric tables.
diff - Use difference method to iterate within image.
idiff - Use integer iteration technique.

- -zeropad Zeropad factor. A setting of 1 is optimal whereas a zeropad of 0 performs no zero padding. Settings greater than 1 perform additional zero padding, but without any significant output difference.

Parameter	Options
- -`filter`	Selects which filter to apply to each projection. To properly reconstruct an image, this filter should consist of the the absolute value of distance from zero frequency optionally multiplied by a smoothing filter. The optimal filters to use are: `abs_bandlimit` `abs_cosine` `abs_hamming` `abs_hanning`
- -`filter-parameter`	Sets the alpha level for Hamming window. This parameter adjusts the smoothing of the Hamming filter and can range from `0` to `1`. At a setting of `1`, the Hamming filter is the same as the bandlimit filter. At a setting of `0.54`, the Hamming filter is the same as the Hanning window.
- -`filter-method`	Selects the filtering method. For large numbers of detectors, `rfftw` is optimal. For smaller numbers of detectors, `convolution` might be a bit faster. `convolution` `fourier` - Uses simple Fourier transform. `fourier-table` - Optimizes Fourier transform by precalculating trigometric functions. `fftw` - Uses complex-valued Fourier transform with the fftw library. `rfftw` - Uses optimized real/half-complex Fourier transform.

- -`filter-generation`	Selects the filter generation. With convolution, `direct` is the proper method to select. With any of the frequency methods, `inverse-fourier` is the best method. `direct` `inverse-fourier`
- -`interpolation`	Interpolation technique during backprojection. `cubic` has optimal quality when the data is smooth. Smooth data is obtained by taking many projections and/or using a smoothing filter. In the absence of smooth data, `linear` gives better results and is many times faster than cubic interpolation. `nearest` - No interpolation, selects nearest point. `linear` - Uses fast straight line interpolation. `cubic` - Uses cubic interpolating polynomial.
- -`backprojection`	Selects the backprojection technique. A setting of `idiff` is optimal. `trig` - Use trigometric functions at each image point. `table` - Use precalculated trigometric tables. `diff` - Use difference method to iterate within image. `idiff` - Use integer iteration technique.
- -`zeropad`	Zeropad factor. A setting of `1` is optimal whereas a zeropad of `0` performs no zero padding. Settings greater than `1` perform additional zero padding, but without any significant output difference.