dicom-codec-js

DICOM Codecs for JavaScript

Features

Currently Implemented:

• JPEG-LS decoding
• HTJ2K encoding

Short Term:

• JPEG-LS encoding
• HTJ2K decoding
• JPEG2000 encoding
• JPEG2000 decoding

Longer Term:

• the rest of the DICOM transfer syntaxes (JPEG baseline, rle, etc)

Building

This project uses git submodules for external dependencies. You must do the following first:

git submodule update --init --recursive

API

decode

async function that decodes an image

Parameters:

• compressedImageFrame - Uint8Array with the compressed image frame bytes
• sourceTransferSyntaxUID - String with the transfer syntax uid of the compressed image frame
• imageInfo - Object
  • rows - Number with the image rows/height
  • columns - Number with the image columns/width
  • bitsPerPixel - Number with bits per pixel
  • componentsPerPixel - Number with number of components per pixel.
  • signed - Boolean true if pixel data is signed, false if unsigned

Returns:

• Object
  • imageFrame - Uint8Array with the uncompressed image frame bytes
  • imageInfo - Object
    • rows - Number with the image rows/height
    • columns - Number with the image columns/width
    • bitsPerPixel - Number with bits per pixel
    • componentsPerPixel - Number with number of components per pixel.
    • signed - Boolean true if pixel data is signed, false if unsigned
  • encodeOptions - Object with contents specific to each codec (see below)

encode

async function that encodes an image

Parameters:

• imageFrame - Uint8Array with the uncompressed image frame bytes
• targetTransferSyntaxUID - String with the transfer syntax uid to encode the image frame as
• imageInfo - Object
  • rows - Number with the image rows/height
  • columns - Number with the image columns/width
  • bitsPerPixel - Number with bits per pixel
  • componentsPerPixel - Number with number of components per pixel.
  • signed - Boolean true if pixel data is signed, false if unsigned
• encodeOptions - Object - contents specific to each codec (see below)

Returns:

• Object
  • encodedImageFrame - Uint8Array with the encoded image frame bytes
  • imageInfo - Object
    • rows - Number with the image rows/height
    • columns - Number with the image columns/width
    • bitsPerPixel - Number with bits per pixel
    • componentsPerPixel - Number with number of components per pixel.
    • signed - true if pixel data is signed, false if unsigned
  • encodeOptions - Object - contents specific to each codec

transcode

async function that transcodes an image (decodes and then encodes)

Parameters:

• compressedImageFrame - Uint8Array with the compressed image frame bytes
• sourceTransferSyntaxUID - String with the transfer syntax uid of the compressed image frame
• imageInfo - Object
  • rows - Number with the image rows/height
  • columns - Number with the image columns/width
  • bitsPerPixel - Number with bits per pixel
  • componentsPerPixel - Number with number of components per pixel.
  • signed - Boolean true if pixel data is signed, false if unsigned
• targetTransferSyntaxUID - String with the transfer syntax uid to encode the image frame as
• encodeOptions - Object - contents specific to each codec (see below)

Returns:

• Object
  • encodedImageFrame - Uint8Array with the encoded image frame bytes
  • imageInfo - Object
    • rows - Number with the image rows/height
    • columns - Number with the image columns/width
    • bitsPerPixel - Number with bits per pixel
    • componentsPerPixel - Number with number of components per pixel.
    • signed - true if pixel data is signed, false if unsigned
  • encodeOptions - Object - contents specific to each codec

TransferSyntax Specific Encoding Options

JPEG2000 / OpenJPEG

TransferSyntaxUIDs:

• 1.2.840.10008.1.2.4.90 JPEG 2000 Image Compression (Lossless Only)
• 1.2.840.10008.1.2.4.91 JPEG 2000 Image Compression

Encode Options:

• Object
  • decompositions - Number (default is 5)
  • lossless - Boolean (default is true)
  • progressionOrder - Number - one of the following
    • 0 LRPC
    • 1 RLCP
    • 2 RPCL (default)
    • 3 PCRL
    • 4 CPRL
  • blockDimensions - Number - default is 64 (64x64)
  • encodeLayerCount - Number - default is 1
  • layerCompressionRatios - Array of Numbers with length === encodeLayerCount

JPEG-LS

TransferSyntaxUIDs:

• 1.2.840.10008.1.2.4.80 JPEG-LS Lossless Image Compression
• 1.2.840.10008.1.2.4.81 JPEG-LS Lossy (Near-Lossless) Image Compression

Encode Options:

• Object
  • interleaveMode - Number - one of the following
    • 0 - None (RRRRGGGGBBBB)
    • 1 - Line (RRGGBBRRGGBB)
    • 2 - Sample (RGBRGBRGBRGB)
  • nearLossless - Number - NEAR parameter - default is 0, higher numbers produce lossy images

HTJ2K

TransferSyntaxUIDs:

• "HTJ2K"

Encode Options:

• Object
  • decompositions - Number (default is 5)
  • lossless - Boolean (default is true)
  • quantizationStep - Number (default is -1.0)
  • progressionOrder - Number - one of the following
    • 0 LRPC
    • 1 RLCP
    • 2 RPCL (default)
    • 3 PCRL
    • 4 CPRL
  • blockDimensions - Number - default is 64 (64x64)