Computer Vision API - Can't convert to binary from Base64

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Posted on 1 Sep 2021 07:05:45 by Stanza

Hi,

I am using Computer Vision API action Optical Character Recognition (OCR) to Text

I have a canvas app that takes a picture and triggers a flow.

When the flow runs it does not recognise the text.

I have built my Flow based on the examples online.

As per my understanding I need to convert the base64 text to binary for the OCR to read the image.

However I get an error when I try to convert it :

Unable to process template language expressions in action 'Compose_2' inputs at line '1' and column '8993': 'The template language function 'base64ToBinary' was invoked with a parameter that is not valid. The value cannot be decoded from base64 representation.'.

My flow:

If I do not convert the image

Any ideas ?

Stanley

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Stanza 21 on 03 Sep 2021 at 02:53:18

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Re: Computer Vision API - Can't convert to binary from Base64

Ok here's the news, turns out the API doesn't recognise handwritten running writing (at the moment).
I scanned an image with block text and it worked !
Stanza 21 on 02 Sep 2021 at 06:32:36

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Re: Computer Vision API - Can't convert to binary from Base64

Hi @rrovira,

I managed to get rid of the error. However, now the Flow runs with no error but I am getting blank text, so the API is not detecting my image.

PowerApps setup is:
PowerApps button to capture image:
OnSelect:

ClearCollect(PicCollection, Camera1.Stream)

PowerApps button to send to Flow:
OnSelect:

TakePictureV2.Run(First(PicCollection).Url)

Flow setup:

I am under the impression that we need to convert using dataUriToBinary function so I have supplied the photo.url as input from PowerApps.
I have also created the file in OneDrive as per the examples on the internet.
The files I have scanned are below. Is the API not able to recognise these images?
I have tried using a business card and same result - all return blank
rrovira Microsoft Employee on 01 Sep 2021 at 17:54:20

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Re: Computer Vision API - Can't convert to binary from Base64

Hello, @Stanza!

What kind of data is the second compose returning? Are you sure it's returning a Base64 string?

Cheers,
Rodrigo!