OCR reading issue

[flysofast]

It worked really well. Thanks a lot. But when I did some OCR on the documents by Tesseract, the results were really weird (as it still showed up perfectly on ImageView control).
I decided to save the image before any image processing (right after it's taken in MAImagePickerController) then did OCR reading, it worked again!
I think there must be something in the image processing section that I haven't figured it out.
It also works with the final adjusted image if I go to Photos, do some minor edits and press "Save".

Please forgive my lack of skills. Thanks again for your fantastic work!