This might be relevant for us since we're often managing customer documents in our apps.
I played around with the library and this is what I found:
Tesseract can detect words from the following sources (from the README):
<img>
, <video>
, or <canvas>
elementCanvasRenderingContext2D
(returned by canvas.getContext('2d')
)File
object (from a file or drag-drop event)Blob
objectImageData
instance (an object containing width, height and data properties)