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5.8.5.4.1.1. Advanced OCR Reading - OCR Engine
In the OCR Engine tab it is possible to change the OCR Engine being used to extract OCR data from the current zone and apply a few default image processing filters.
Background Filter Background color removal. Very useful when there is a colored background or a lot of noise behind the text in the image.
Auto Adjust Auto adjust filter for the reading area. Useful for scanned documents where the data moves a few centimeters from document to document.
Most of the time this options will provide desirable results. Whenever you are struggling with your OCR reading try disabling it.
On native PDF files this option tends to cause issues so it should be disabled.
Noise Filter A quick noise filter that can improve reading on scanned documents with noise on the image.
Erode Filter The erode filter will make all the lines on the image thinner.
Very useful when the font used to generate the image is very thick specially with numbers.
Dilate Filter The dilate filter will make all the lines in the image thicker, having the opposite effect of the erode filter.
Just like the erode filter, there are two level for the dilate filter.
