.\" -*- NROFF -*- .\" .TH "pjrec" "1" "" "Kevin Rosenberg" "Engineering" .SH "NAME" pjrec \- reconstruction from projections .SH "SYNOPSIS" .B pjrec projection\-file image\-file nx\-image ny\-image [OPTIONS] .SH "DESCRIPTION" \fIpjrec\fP takes projection data from \fIraysum\-file\P and produces an (IF) image file \fIimage\-file\fP, of size \fInx\-image\fP by \fIny\-image\fP pixels, containing the reconstructed image. .SH "OPTIONS" \fIpjrec\fP accepts the following options, which control the reconstruction algorithm: .TP 12 .B \-\-interp Interpolation method during backprojection .RS .TP .B nearest Nearest neighbor interpolation .TP .B linear Linear interpolation .RE .TP 12 .B \-\-preinterpolate Preinterpolation factor (default = 1). Used only with frequency\-based filtering .TP 12 .B \-\-filter Filter name .RS .TP 15 .B abs_bandlimit Abs * Bandlimiting (default) .TP 15 .B abs_sinc Abs * Sinc .TP 15 .B abs_cosine Abs * Cosine .TP 15 .B abs_hamming Abs * Hamming .TP 15 .B shepp Shepp\-Logan .TP 15 .B bandlimit Bandlimiting .TP 15 .B sinc Sinc .TP 15 .B cosine Cosine .TP 15 .B triangle Triangle .TP 15 .B hamming Hamming .RE .TP 12 .B \-\-filter\-method Filter method before backprojections .RS .TP 15 .B convolution Spatial filtering (default) .TP 15 .B fourier Frequency filtering with discete fourier .TP 15 .B fourier_table Frequency filtering with table lookup fourier .TP 15 .B fft Fast Fourier Transform .RE .TP 12 .B \-\-zeropad n Set zeropad level (default = 0). set n to number of powers to two to pad .TP 12 .B \-\-filter\-generation Filter Generation mode .RS .TP 12 .B direct Use direct filter in spatial or frequency domain (default) .TP 12 .B inverse_fourier Use inverse fourier transform of inverse filter .RE .TP 12 .B \-\-backproj Backprojection Method .RS .TP .B trig Trigometric functions at every point .TP .B table Trigometric functions with precalculated table .TP .B diff Difference method .TP .B diff2 Optimized difference method (default) .TP .B idiff2 Optimized difference method with integer math .TP .B idiff3 Highly\-optimized difference method with integer math .RE .TP 12 .B \-\-filter\-param Alpha level for Hamming filter .TP 12 .B \-\-trace Set tracing to level: .RS .TP 12 .B none No tracing (default) .TP 12 .B console Text level tracing .RE .TP 12 .B \-\-verbose Turn on verbose mode .TP 12 .B \-\-debug Turn on debug mode .TP 12 .B \-\-version Print version .TP 12 .B \-\-help Print a terse help message .SH "AUTHORS" Kevin Rosenberg, M.D. .SH "HISTORY" CTSim was begun in 1983 using MS\-DOS and an EGA display adapter. In 1999 it was ported to GNU/Linux and later ported to Microsoft Windows. .SH "SEE ALSO" .BR ctsim (1) .BR ctsimtext (1) .BR if1 (1) .BR if2 (1) .BR ifinfo (1) .BR linogram (1) .BR phm2helix (1) .BR phm2if (1) .BR phm2pj (1) .BR pj2if (1) .BR pjHinterp (1) .BR pjinfo (1)