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I'm developing an application for hololens that reads qr code. Even having used the sample code from microsoft the reading is difficult. If I try to read a qrcode with my app closed, the native hololens reader reads it very quickly. But in the same position, when I open my app, the reading takes a while to detect or sometimes it doesn't (if it's a qrcode already read previously).
I used the example code in https://github.com/microsoft/MixedReality-QRCode-Sample
Do you have any tip? Any settings I might have missed? Is there any example code for the native hololens reader?
I found on the microsoft page a recommendation to filter the qrcodes by date. But I don't understand where should this filter be made? Do you have any examples?
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Hello, welcome to Microsoft Q&A,
May I know which native HoloLens reader do you use? According to QR code tracking overview, Windows Mixed Reality devices detect QR codes at the system level in the driver. When the device is rebooted or the driver restarts, the detected QR codes history is cleared. QR codes redetected are treated as new objects. I am not sure which “native hololens reader” you are using, but native implementation is based on Microsoft.MixedReality.QR and the scan time should be similar.
The native I meant is the one that comes with hololens and shows a green square with a play button. Yes I know it uses the same drivers and Microsoft.MixedReality.QR. I'm using it too.
But there are some settings that need to be done and I didn't find it in the example(https://github.com/microsoft/MixedReality-QRCode-Sample).
For example, the documentation on the QR code tracking overview mentions about the history is cleared when you restart the drivers and then suggests "We recommend configuring your app to ignore QR codes older than a specific timestamp, which can be specified within the app ". But I'm having trouble doing this. I tried to clear the qrCodesList in the QRCodesManager (in the example code https://github.com/microsoft/MixedReality-QRCode-Sample) , but it didn't work. Do you have an example of how to do this?
Hello, welcome to Microsoft Q&A,
clear the qrCodesList in the QRCodesManager
Currently it is not supported to programmatically manage the cached QR code list in the system. The "qrCodesList" that you are referred from https://github.com/microsoft/MixedReality-QRCode-Sample is locally maintained data structure and data are added when "QRCodeWatcher_Added" event is triggered (changes according to specific events). Removing all data in this list won't have effects on the cached data in the system. Rebooting device or restart driver is the only method. The current QRcode version has limits, and the product team is working on it to improve this feature, but for now all the supported APIs are listed at [QR Code tracking API reference] (https://learn.microsoft.com/en-us/windows/mixed-reality/develop/native/qr-code-tracking-cs-cpp#qr-code-tracking-api-reference).
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