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Problem using ImageTags from Holotoolkit

I'm trying to use some functions from HoloToolkit, where no examples in Holotoolkit-Unity exists:

ImageTagLocation, ImageTagLocationListener and so on..

So far I managed some implemantion in Unity, but I'm stuck on detecting ImageTags ...

In my case, the Imagetaglistener fires an Event for OnTagLocatingCompleted() but not for OnTagLocated().

Has anybody an example of using the Holotoolkit for detecting ImageTags (AprilTags ...) ?


  • What library are you using that defines ImageTagLocation and ImageTagLocationListener?

    I've been using Vuforia with great success on the HoloLens, but I'm always interested in knowing what the options are.

    Our Holographic world is here

    RoadToHolo.com      WikiHolo.net      @jbienz
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  • I'm using the SharingClient.dll (from Holotoolkit) which is exposed thru the Holotolkit-Unity (HoloToolkit.Sharing;).
    There are several classes which I'm using.
    I subclassed the ImageTagLocationListener ... but I'm not sure, if it really works

    My ImageTagDetector.cs:

    using System.Collections;
    using System.Collections.Generic;
    using UnityEngine;
    using HoloToolkit.Sharing;

    public class ImageTagDetector : ImageTagLocationListener
    public event System.Action TagLocatedEvent = null;
    public event System.Action TagLocatingCompletedEvent = null;

    public ImageTagDetector()
    public override void OnTagLocated(ImageTagLocation location)
        Debug.Log("Tag located.");
        if (this.TagLocatedEvent != null)
    public override void OnTagLocatingCompleted()
        Debug.Log("Tags completed.");
        if (this.TagLocatingCompletedEvent != null)


    And what I've done..

    private ImageTagManager itm = null; //from Holotoolkit.Sharing
    private ImageTagDetector td = null; //my subclassed ImageTagLocationListener


    td = new ImageTagDetector();
    td.TagLocatedEvent += this.onTagLocated;
    td.TagLocatingCompletedEvent += this.onAllTagsCompleted;

    //texDat are the pixels (byte[])
    bool b = itm.FindTags(texDat1, tex.width, tex.height, 1, td);

    void onTagLocated(ImageTagLocation location)

    void onAllTagsCompleted()

    If I'm looking into the source it seems the workerThread does'nt work ...
    It would be that good to have an example project / scene in Holotoolkit-Unity.

  • And:
    ... I'm also using Vuforia with success but sometimes it would be good to have an alternative for simple markers (VuMarks are an option but FrameMarkers are obsolete) ...

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