Osimis Web Viewer

The Osimis' Web Viewer provides medical image visualization straight from the browser.

It is distributed as a plugin to Orthanc. In other words, the viewer can be connected to most modalities, but also leveraged through Orthanc's strong architectural extensibility.

2D rendering is supported with the usual tools:

  • Zooming
  • Panning
  • Windowing
  • Length Measurement
  • Angle Measurement
  • Point/Circle/Rectangle of Interest
  • Image Flipping/Rotation
  • Multiframe support

Have a look at our blog.


A demo of the viewer is available at those links:

  • IRM study.
  • Full demo, embedded within the Orthanc Explorer. Other studies are available from there.

What's new

See the release notes.

Installation & Usage

The latest stable version is available here.

Nightly builds are available here. They are still unstable at the moment.

We recommend to download the binaries for Windows and Mac OS X & the docker image for Linux.

This article details the installation process on Windows.

This procedure details the docker image installation process on Linux.

For Mac OS X, the procedure is very similar to the windows' one. Unzip the downloaded folder and double click on the startOrthanc.command file.


Orthanc is configurable via a JSON file. This plugin provide a few optional options as well.

   * General configuration of Orthanc

  /* ... (see the Orthanc documentation for the other options) ... */

   * Orthanc options having significant impact on the Web Viewer

  // Enable the HTTP server. If this parameter is set to "false",
  // Orthanc acts as a pure DICOM server. The REST API and Orthanc
  // Explorer will not be available. 
  "HttpServerEnabled" : true,

  // HTTP port for the REST services and for the GUI
  "HttpPort" : 8042,

  // When the following option is "true", if an error is encountered
  // while calling the REST API, a JSON message describing the error
  // is put in the HTTP answer. This feature can be disabled if the
  // HTTP client does not properly handles such answers.
  "HttpDescribeErrors" : true,

  // Enable HTTP compression to improve network bandwidth utilization,
  // at the expense of more computations on the server. Orthanc
  // supports the "gzip" and "deflate" HTTP encodings.
  // May be disabled to avoid useless image recompression overhead.
  "HttpCompressionEnabled" : true,

  // Set the timeout for HTTP requests issued by Orthanc (in seconds).
  "HttpTimeout" : 10,

  // Whether remote hosts can connect to the HTTP server
  // In development mode, useful to set to true when using docker on OSX.
  "RemoteAccessAllowed" : false,

  // The maximum number of active jobs in the Orthanc scheduler. When
  // this limit is reached, the addition of new jobs is blocked until
  // some job finishes.
  "LimitJobs" : 10,

  // Enable or disable HTTP Keep-Alive (deprecated). Set this option
  // to "true" only in the case of high HTTP loads.
  "KeepAlive" : false,

  "Plugins" : [
    // Uncomment one of the following lines according to your platform.  
    // Update the path to the DLL on your system.  The path is relative to the working folder
    // Orthanc will start from.  If you are unsure what the working folder is,
    // use and absolute path

    // "C:\\Program Files (x86)\\Orthanc\\Orthanc Server 1.1.0\\OsimisWebViewer.dll" // for Windows 
    // "" // for Linux
    // "libOsimisWebViewer.dylib" // for OSX

   * Osimis WebViewer Configuration
  "WebViewer" : {
    // Show the `download study` button in the frontend.
    // You may want to disable this feature if you disable access to
    // the underlying REST route for authentication reasons.
    // Default: true
    "StudyDownloadEnabled": true,

    // Display MPEG-4 DICOM video (non-bd only) within the frontend. You
    // may disable this feature if you disable access to the underlying
    // REST route for authentication reasons.
    // Default: true
    "VideoDisplayEnabled": true,

    // Store image annotations made by users as Orthanc Attachment 9999 and
    // retrieve them autommatically each time the viewer is opened.
    // Default: false
    "AnnotationStorageEnabled": false,

    // This option displays a button on each viewport. When the user clicks 
    // on the button, a new DICOM series is created with the image of the
    // viewport, including the annotations. You must ensure your server allows
    // large requests. You must also includes a new dicom tag in the
    // dictionary (see the Dictionary json attribute below).
    // Default: false
    "KeyImageCaptureEnabled": false

    // Store low/high quality images in a short term cache
    "ShortTermCacheEnabled": true,

    // Path where the short term cache is stored
    "ShortTermCachePath": "/OrthancStorage/WebViewerCache",

    // Maximum size of the short term cache (in MB)
    "ShortTermCacheSize": 1000,

    // Start pre-computing the low/high quality images as soon as they are 
    // received in Orthanc.
    "ShortTermCachePrefetchOnInstanceStored": false,

    // Number of threads used by the short term cache to pre-compute the
    // low/high quality images.
    "ShortTermCacheThreads": 4,

    // Display cache debug logs (mainly for developers)
    "ShortTermCacheDebugLogsEnabled": false,

    // Preload high quality images on the frontend before the user actually
    // needs them
    "HighQualityImagePreloadingEnabled": true


The Osimis' Web Viewer is licensed under the AGPL license. See the COPYING file. We also kindly ask scientific works and clinical studies that make use of Orthanc to cite Orthanc in their associated publications. Similarly, we ask open-source and closed-source products that make use of Orthanc to warn us about this use. You can cite S. Jodogne's work using the following BibTeX entry:

author = {Jodogne, S. and Bernard, C. and Devillers, M. and Lenaerts, E. and Coucke, P.},
title = {Orthanc -- {A} Lightweight, {REST}ful {DICOM} Server for Healthcare and Medical Research},
booktitle={Biomedical Imaging ({ISBI}), {IEEE} 10th International Symposium on}, 
address={San Francisco, {CA}, {USA}}

Contact & Bug/Feedback Report

Any question/feedback/bug report are well appreciated. You may send them by mail to osimis' support at

The full bug/feedback report procedure is available in the procedures/ file.

Authentification Proxy Development & Plugin's routes

See the procedures/ file.


Folder structure

Six folders are available at the root:

  • backend/ contains the C++ plugin source code (& cmake build process).
  • frontend/ contains the HTML/JavaScript source code (& gulp build process).
  • reverse-proxy/ contains a reverse proxy suitable for development.
  • demo/ contains a standalone docker, proxied version of orthanc and the viewer with sample files.
  • scripts/ contains global demo building scripts, it is mostly used by the Continuous Integration System. It also contains scripts to build/run the web viewer demo in a docker environment.
  • tests/ contains the integration tests.


See the procedures/ file.


See the procedures/ file.


See the procedures/ file.

Release procedure

See the procedures/ file. The procedures/ file will be mentionned.

Pulling changes back from orthanc-webviewer-plugin

See the procedures/ file.