I played around with some image pre-processing and the image itself looks pretty good after that:
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There is some trained data on seven segment displays but I have no idea on how to get these into the node red node (or is it called module or so?)
Another option I tried was the following integration: Seven Segments OCR - Home Assistant
But hass.io does not know the command “ssocr” even the integration is installed and therefore it’s hard to test.