Minimalist OCR macro not working to read from and write to clipboard

I am using possibly the smallest OCR macro possible. It seems as if there should be nothing to debug. And it's not working.

Here's the macro:

It simply takes whatever is on the clipboard, runs English OCR on it, and puts the result back in the clipboard.

I use it by pressing Ctrl+Cmd+Shift+4, dragging to select the area. That system hotkey puts the selected image in the clipboard. I then press F1 to run the macro, and I then paste the text from the clipboard where I want it, using Cmd+v.

In theory.

But when I select this image:

what I get as the OCR result is:

May be an image of text that says ‘no one is asking you to APOLOGIZE FOR BEING
TU RRC kara anal
Pe REO ee eee
TEA CHTCR AAEM TV Retna TnMstat sana stelt ea

It's like it gets the first line exactly right and the rest is nonsense, not even close. I can make it "work" by selecting one line of text at a time and pasting them together.

One thought that occurred to me, which I haven't tested, is that it is saving that first line, as it is completed, directly into the system clipboard before reading the rest of the clipboard for OCR processing, thereby messing up the source image. I would hope that was impossible, but ...

Any suggestions?

Looks like some weird bug in the Tesseract engine. I checked, and I get the same result as you, and checked that there was no encoding issue or such, the engine simply returns that garbled response after the first line.

It looks to be a bug, since it gets the first line right (as right as expected for OCR anyway), and if you chop out each line, it gets them right as well.

Tesseract is known to not be fond of white on black text, and indeed if you invert the text:


the OCR works fine. Unfortunately, Keyboard Maestro does not have any action that will invert images.

Images can be inverted with ImageMagick or an Automator workflow.
See this post: Inverting Image Colors Before OCR - #9 by JimmyHartington

1 Like

Thanks @JimmyHartington and @peternlewis.

Yes, it works consistently well on black text and white background.

Peter, could you add a note about this limitation to the OCR doc, perhaps near where the Tesseract engine is mentioned?