An easy-to-use Grassroots DICOM Library wrapper designed to convert DICOM files transfer syntaxes and photometric interpretation.
You need CMake to build GDCM Library.
cmd
sudo apt-get install cmake
Download CMake directly from www.cmake.org/download page.
Copy this code and make sure you have a DICOM file to test (DICOM file samples).
```rust use std::io::prelude::*; use std::fs::File; use gdcm_conv::{TransferSyntax, PhotometricInterpretation};
// Read input file
let mut ibuffer = Vec::new();
let mut ifile = File::open("test.dcm").unwrap();
ifile.readtoend(&mut ibuffer).unwrap();
// Transcode DICOM file let obuffer = match gdcm_conv::pipeline( // Input DICOM file buffer ibuffer, // Estimated Length None, // First Transfer Syntax conversion TransferSyntax::JPEG2000Lossless, // Photometric conversion PhotometricInterpretation::None, // Second Transfer Syntax conversion TransferSyntax::None, ) { Ok(t) => t, Err(e) => { eprintln!("{}", e); return; } };
// Create output file and save let mut ofile = File::create("output.dcm").unwrap(); ofile.write_all(&obuffer).unwrap(); ```
The gdcm_conv library takes as input the content of the DICOM file. It reuse the source vector allocating an estimated size to avoid cloned memory. The default estimad length is 3 times the input file size, the worst case, changing from a compressed image (like JPEG2000) to raw. Is recommended to use an estimated calculation, to minimize memory allocation.
If the allocated size is not enough, the library will re-allocate to the correct size and execute the FFI function again.
To estimate the output length you could use this aproximation:
``` // MAX HEADER SIZE const MAXHEADERSIZE: usize = 5000;
let a = match bits_allocated { 8 => 1, 16 => 2, };
let b = match photometric_interpretation { "MONOCHROME1" => 1, "MONOCHROME2" => 1, _ => 3, };
let estimadlength = (a * b * rows * columns * numberofframes) + MAXHEADER_SIZE; ```
The library works as a pipeline with a first transfer syntax conversion (PRE-TRANSFER), a photometric conversion and a final transfer syntax conversion (POST-TRANSFER). If you set to None it don't execute the step. Usually, you will use only the first and/or second step.
I setup this way because in some cases is needed two transfer syntax transcoding like this example:
The conversion from JPEG Baseline (Process 1) 1.2.840.10008.1.2.4.50 with YBRFULL or YBRFULL_422 to JPEG2000 lossles, you need to change to Explicit Little Endian transfer syntax, then to an RGB photometric interpretation and finally to JPG2000, to avoid GDCM color interpretation issue.