QR-Code Scan issues with HoloLens2

[BCAG_David]

Dear All

Scanning a QR-Code with Vuforia View on the HoloLens 2 is working only once in a while. If you start Vuforia View on the HoloLens 2 and immediately look at the QR-Code even before Vuforia View is fully started up it works. But if you wait until Vuforia View is started up and then look at the QR-Code it works mostly never or very rarely.

For me it's not that bad but if I give the HoloLens to someone from the field service to do an AR-Experience and he's not able to start it easily it's impractical.

Is this a known issue? 

Best regards

David

[RolandRaytchev]

Did you check with the last version.? According what's New in 8.5.9 - there is improvment with QR code for HoloLens 2:  https://community.ptc.com/t5/Vuforia-Studio-and-Chalk-Tech/What-s-new-in-Vuforia-Studio-8-5-9/ta-p/669917

[BCAG_David]

Thanks for your answer. I now updated to version 8.5.9 and tried it again and it's still not reliable. When i let Vuforia View start up and then want to scan it doesn't work. If I immediately look at the QR-Code after pressing the Vuforia View button then it works.

[RolandRaytchev]

Ok, may be this is something what we need to report to the dev team.

But first let clarify the issue more detailed.

1.) what means here scan - what widget is used here- it is the default scanning for experience when you enter the Vuforia View app at the first time or  do you call the QR widget in some context later.

Depending of these different options we can:

1.) use an command to restart scan according to http://support.ptc.com/help/vuforia/studio/en/#page/Studio_Help_Center%2FEyewearViewAndHololens.html

“Hey View, scan.”

Or

“Hey View, Scan mode.”

2.) if you try to use the scan widget , e.g. embed in a popup , you can start it later  when it required for scanning e.g. via button

What is for me strange is this statement "before Vuforia View is fully started up it works." - what this means – some actions done by your vuforia  studio project? Because the scan mode is the first thing which is called when you start the Vuforia View app. So that when the scanning is called it was already initialized. Therefore I will understand this statement more as - your application/here the Vuforia Studio project  will perform some tasks for example listener on modelLoad and then it goes to scan mode using the scan widget? Is this correct or could you explain?

Thank you!

[BCAG_David]

It's about the default-scanning in order to start the experience. In the experience itself it doesn't scan anything. I use the QR-Code in Vuforia Studio from "Share Experience" to start the experience. I also tried to restart the scan-process with "Hey View, Scan" but it remains with not be able to scan the QR-Code.

With "before Vuforia View is fully started up it works.", I mean the short time between clicking on the Vuforia View App to start it and until the 4 green corners are visible to scan QR-Codes or Thingmarks. If I'm looking at the QR-Code before these 4 green corners are visible it scans the QR-Code immediately and the experience starts. But if I wait until these 4 green corners are visible and then scan the QR-Code it doesn't work.

So this issue is before the experience is loaded. I also tried it with an nearly empty experience and it's the same behaviour.

In the meanwhile I added a thingmark to the experience and with scanning the thingmark it has no issue.

[RolandRaytchev]

Thanks for the feedback.

Unfortunately currently I have only a HoloLens 1 device and there I could not reproduce the issue -So will check with dev team if there someone has an Idea what could be the reason.

[RolandRaytchev]

according dev team there is no general issue for scanning with the HoloLens 2 device- Here a short feedbacck: "dont see a problem scanning on my hl2"

to check:

"-is device updated to latest OS etc.?

-also check network connection - it may scan correctly, but if it cannot get to the network and the GXI, you wont get very far"

[dmforbes]

I realize this discussion is a year old.  I recently received my HL2, and the only way I am able to get the HL2 to scan a QR code for View, is to have the barcode in view asap, while the app is loading.  if I wait for View to fully load, and then place the QR code in sight, I cannot get the experience to launch.  i can say ALL of the commands, and I have only 1 time had the experience finally launch.

[DmitryTsarev]

@dmforbes 

Do you mean specifically QR codes or ThingMarks?

I've recently been tinkering about with HoloLens 2 and didn't have any issues with regards to scanning ThingMarks. Didn't do anything besides setting ES URL with QR codes, though.

[dmforbes]

he issue was, that I was not waiting long enough after saying "Hey View"...  then pause, then "Command".  i was stating this in one sentence, not giving the HL2 time to process the voice.  all is good now

[mbommas]

August 2021 and I am having the exact same issues with my Hololens 2. When the app is fully launched, it no longer accepts any QR code. If I look at the QR code while the app is launching, it works. Thank you very much for this tip. Now I have at least a workaround.

[AC_9741335]

I am also having the same issue with my Hololens 2. I am unable to scan a QR code to start an experience. After reading this thread, I tried looking at the code while View was launching and that worked, as others have noted.

[RolandRaytchev]

Hi, I saw this issue - so possibly in the mean time in the current release it is not so relevant any more

The pervious issue according description HL 2 device is not able to read or recognize the QR code. One question: From where tjre iser  did you read the QR code ? Is the QR code  printed or user tired try  read it  from computer screen. Possibly this is  issue with the resolution or the QR code as scaled on printing with different factor in x and y direction.

Also the correct used light or reflection on the medium could be an issue.

When I for example will scan a code form laptop (e.g. Studio ) and look on the QR code the HoloLens often HoloLens2 will not recognize it. So I do simple scale  the QR code by simple zoom in or zoom out and this immediately will recognize the code as such.

With the HoloLens 2 device and printed code and  the same effect could be observed when we simple go near to the QR code so that the scan window will  have approximately the same size as the printed code and then slowly go near to the QR printed code or go away from it.

So far I know this issue was very often reported in older releases (1 or 2 release earlier as the current release) so that means it will be recommend to check if your Studio is updated and you Vuforia View app on the HoloLens 2.0 is also up to date. Also it is recommend that the OS for your HL2 device is also updated. So far I know this behavior was improved in the last release but also issue is based on the Hololens API (native from Microsoft)

In case that  issue occurs with a printed QR code, please,  check that QR code is printed as  a quadrat with the same width and high means there should not be a  different scale in x and y. And also the printed size is this what we can expect when we scan from at least  1 meter distance (should have the size of the QR code as the  window of the scan window)

[TonyZhang]

@BCAG_David,

Try increasing the size of QR code and scan, if printing it out, make it fully take up an A4 size paper to see if it makes it easier to recognize the QR code.