---
name: "pjrec"
section: "1"
platform: "linux"
package: "ctsim"
version: "6.0.2-6+b5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/pjrec"
---

# pjrec(1)

reconstruction from projections

## NAME

pjrec - reconstruction from projections

## SYNOPSIS

**pjrec projection-file image-file nx-image ny-image \[OPTIONS\]**

## DESCRIPTION

*pjrec* takes projection data from *raysum-fileP and produces an* *(IF) image file image-file, of size nx-image by* *ny-image pixels, containing the reconstructed image.*

## OPTIONS

*pjrec accepts the following options, which control the* *reconstruction algorithm:*

- **--interp**

  *Interpolation method during backprojection*

  - **nearest**

    *Nearest neighbor interpolation*

  - **linear**

    *Linear interpolation*

- **--preinterpolate**

  *Preinterpolation factor (default = 1).  Used only with frequency-based*  *filtering*

- **--filter**

  *Filter name*

  - **abs\_bandlimit**

    *Abs \* Bandlimiting (default)*

  - **abs\_sinc**

    *Abs \* Sinc*

  - **abs\_cosine**

    *Abs \* Cosine*

  - **abs\_hamming**

    *Abs \* Hamming*

  - **shepp**

    *Shepp-Logan*

  - **bandlimit**

    *Bandlimiting*

  - **sinc**

    *Sinc*

  - **cosine**

    *Cosine*

  - **triangle**

    *Triangle*

  - **hamming**

    *Hamming*

- **--filter-method**

  *Filter method before backprojections*

  - **convolution**

    *Spatial filtering (default)*

  - **fourier**

    *Frequency filtering with discete fourier*

  - **fourier\_table**

    *Frequency filtering with table lookup fourier*

  - **fft**

    *Fast Fourier Transform*

- **--zeropad n**

  *Set zeropad level (default = 0).  set n to number of powers to two to pad*

- **--filter-generation**

  *Filter Generation mode*

  - **direct**

    *Use direct filter in spatial or frequency domain (default)*

  - **inverse\_fourier**

    *Use inverse fourier transform of inverse filter*

- **--backproj**

  *Backprojection Method*

  - **trig**

    *Trigometric functions at every point*

  - **table**

    *Trigometric functions with precalculated table*

  - **diff**

    *Difference method*

  - **diff2**

    *Optimized difference method (default)*

  - **idiff2**

    *Optimized difference method with integer math*

  - **idiff3**

    *Highly-optimized difference method with integer math*

- **--filter-param**

  *Alpha level for Hamming filter*

- **--trace**

  *Set tracing to level:*

  - **none**

    *No tracing (default)*

  - **console**

    *Text level tracing*

- **--verbose Turn on verbose mode**

  - **--debug Turn on debug mode**

  - **--version Print version**

  - **--help Print a terse help message**

  ## AUTHORS

*Kevin Rosenberg, M.D. \<kevin@ctsim.org\>*

## 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.*

## SEE ALSO

[**ctsim**(1)](/ctsim/1.md) [**ctsimtext**(1)](/ctsimtext/1.md) [**if1**(1)](/if1/1.md) [**if2**(1)](/if2/1.md) [**ifinfo**(1)](/ifinfo/1.md) [**linogram**(1)](/linogram/1.md) [**phm2helix**(1)](/phm2helix/1.md) [**phm2if**(1)](/phm2if/1.md) [**phm2pj**(1)](/phm2pj/1.md) [**pj2if**(1)](/pj2if/1.md) [**pjHinterp**(1)](/pjHinterp/1.md) [**pjinfo**(1)](/pjinfo/1.md)