dcmjs-codecs

DICOM file and dataset transcoding for Node.js and browser using Steve Pieper's dcmjs library.

Note

This effort is a work-in-progress and should not be used for production or clinical purposes.

Install

Node.js

npm install dcmjs-codecs

Browser

<script type="text/javascript" src="https://unpkg.com/dcmjs"></script>
<script type="text/javascript" src="https://unpkg.com/dcmjs-codecs"></script>

Build

npm install
npm run build

Build codecs WebAssembly (optional)

cd wasm
./build.sh

Emscripten SDK (emsdk) is required.

Supported Transfer Syntaxes

• Implicit VR Little Endian (1.2.840.10008.1.2)
• Explicit VR Little Endian (1.2.840.10008.1.2.1)
• Explicit VR Big Endian (1.2.840.10008.1.2.2)
• RLE Lossless (1.2.840.10008.1.2.5)*
• JPEG Baseline - Process 1 (1.2.840.10008.1.2.4.50)*
• JPEG Lossless, Nonhierarchical, First-Order Prediction - Processes 14 [Selection Value 1] (1.2.840.10008.1.2.4.70)*
• JPEG-LS Lossless Image Compression (1.2.840.10008.1.2.4.80)*
• JPEG-LS Lossy Image Compression - Near-Lossless (1.2.840.10008.1.2.4.81)*
• JPEG 2000 Image Compression - Lossless Only (1.2.840.10008.1.2.4.90)*
• JPEG 2000 Image Compression (1.2.840.10008.1.2.4.91)*
• High Throughput JPEG 2000 Image Compression - Lossless Only (1.2.840.10008.1.2.4.201)*
• High Throughput JPEG 2000 with RPCL Options Image Compression - Lossless Only (1.2.840.10008.1.2.4.202)*
• High Throughput JPEG 2000 Image Compression (1.2.840.10008.1.2.4.203)*

---

*: Syntax is transcoded using the codecs WebAssembly.

Usage

Basic image transcoding

// Import objects in Node.js
const dcmjsCodecs = require('dcmjs-codecs');
const { NativeCodecs, Transcoder } = dcmjsCodecs;
const { TransferSyntax } = constants;

// Import objects in Browser
const { NativeCodecs, Transcoder } = window.dcmjsCodecs;
const { TransferSyntax } = constants;

// Register native codecs WebAssembly.
await NativeCodecs.initializeAsync();

// Create an ArrayBuffer with the contents of the DICOM P10 byte stream.
const transcoder = new Transcoder(arrayBuffer);

// Transcode to a different transfer syntax UID.
transcoder.transcode(TransferSyntax.JpegLosslessProcess14V1);

// Get the transcoded DICOM P10 byte stream in an ArrayBuffer.
const transcodedArrayBuffer = transcoder.getDicomPart10();

Advanced image transcoding

// Import objects in Node.js
const dcmjsCodecs = require('dcmjs-codecs');
const { NativeCodecs, Transcoder } = dcmjsCodecs;
const { Jpeg2000ProgressionOrder, TransferSyntax } = constants;

// Import objects in Browser
const { NativeCodecs, Transcoder } = window.dcmjsCodecs;
const { Jpeg2000ProgressionOrder, TransferSyntax } = constants;

// Create native codecs WebAssembly initialization options.
const initOpts = {
  // Optionally, provide the path or URL to WebAssembly module.
  // If empty or undefined, the module is trying to be resolved 
  // within the same directory.
  webAssemblyModulePathOrUrl: undefined,
  // Optional flag to enable native codecs informational message logging.
  // If not provided, the native codecs informational message logging is disabled.
  logCodecsInfo: false,
  // Optional flag to enable native codecs trace message logging.
  // If not provided, the native codecs trace message logging is disabled.
  logCodecsTrace: false
};
await NativeCodecs.initializeAsync(initOpts);

// Create an ArrayBuffer with the contents of the DICOM P10 byte stream.
const transcoder = new Transcoder(arrayBuffer);

// Create encoding and decoding options.
const encodingDecodingOpts = {
  // JPEG encoding params
  // Optional JPEG quality, in case of JPEG baseline encoding.
  // Sets the libjpeg jpeg_set_quality quality input variable.
  quality: 90,

  // JPEG-LS encoding params
  // Optional JPEG-LS quality, in case of JPEG-LS lossy encoding.
  // Sets the charls allowedLossyError variable.
  allowedLossyError: 10,

  // JPEG 2000 and HT-JPEG 2000 encoding params
  // Optional JPEG progression order, in case of JPEG 2000 and HT-JPEG 2000 encoding.
  progressionOrder: Jpeg2000ProgressionOrder.Lrcp,
  // Optional JPEG 2000 quality, in case of JPEG 2000 lossy encoding.
  // Sets the openjpeg tcp_rates[0] variable.
  rate: 20
};

// Transcode to a different transfer syntax UID.
transcoder.transcode(TransferSyntax.Jpeg2000Lossless, encodingDecodingOpts);

// Get the transcoded DICOM P10 byte stream in an ArrayBuffer.
const transcodedArrayBuffer = transcoder.getDicomPart10();

Please check a live example here.

Related libraries

• dcmjs-dimse - DICOM DIMSE implementation for Node.js using dcmjs.
• dcmjs-imaging - DICOM image and overlay rendering for Node.js and browser using dcmjs.

License

dcmjs-codecs is released under the MIT License.