Handwritten text recognition working poorly on iOS 16 beta ?

Question

Claude31 OP

Created Jun ’22

Replies 3

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That's a follow up of a previous thread.

https://developer.apple.com/forums/thread/707130

I did some test on iOS 16 simulator with Xcode 14ß.

Recognition is very poor. And recognition rate of some single letters (an L or an I for instance) is zero (literally). Same code worked better (success 50% for same single letters) with iOS 15.2.

Did something change on iOS 16 ? I filed a bug report: Jun 7, 2022 at 3:28 PM – FB10066541

Answered by Claude31 in 716679022

I got rapidly an answer from support (thanks):

iOS 16 introduced a new revision of VNRecognizeTextRequest (VNRecognizeTextRequestRevision3). By default, the revision used is determined by the SDK that was linked with the app. You can check the default revision using the defaultRevision property of VNRecognizeTextRequest to verify. So, assuming that you rebuilt your app with the Xcode 14 beta, it is likely that you are now seeing Revision3 results, whereas previously you were likely seeing Revision2 results.

So I changed with: request.revision = 2

And success rate improved significantly.

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Answer 1

Claude31 OP

Jun ’22

Accepted Answer

I got rapidly an answer from support (thanks):

iOS 16 introduced a new revision of VNRecognizeTextRequest (VNRecognizeTextRequestRevision3). By default, the revision used is determined by the SDK that was linked with the app. You can check the default revision using the defaultRevision property of VNRecognizeTextRequest to verify. So, assuming that you rebuilt your app with the Xcode 14 beta, it is likely that you are now seeing Revision3 results, whereas previously you were likely seeing Revision2 results.

So I changed with: request.revision = 2

And success rate improved significantly.

0

Answer 2

dcosel OP

Dec ’22

Thank you!! Saved a lot of banging my head against the wall. Do you happen to know the changes in revision 3? Seems to be a step backwards... at least for my use case.

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Answer 3

Claude31 OP

Jan ’23

Do you happen to know the changes in revision 3?

Recognition is based on machine learning.

I understood that the training base has changed, hence the behaviour. As it is not an algorithm change, which makes it difficult to explicit the differences.

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