OCR engine to capture characters from images

Question

i'm using c# tessnet2 wrapper for Tesseract OCR engine to capture chracters of image files. i been searching everywhere if tessnet2 has any build in functions to overwrite certain characters and saved them into the same image file it's reading but have not found anything in regards to that. so what i'm thinking of doing is creating a new imagine file base on what i'm receiving from tessnet2 but i need to create the new image the same exact way but change just few things in the new created image. i'm not sure if i'm using the correct methology or if there is other c# assemblies out there that allow you to read characters from image file and at the same time allow you to manipulate as you need them.

Answer 1

Good luck--but tess has no way of replacing in the proper font. Raster graphics don't generally store glyph information. Even if it did, you would potentially be in violation of licenses and/or copyrights surrounding the fonts you'd be writing in. I'm not an expert in OCR, but I will confidently say that this is something not readily available out there in the wild.

Answer 2

To expand on Brian's answer: You will need to do this yourself. I have not worked with Tesseract, but I have used the Nuance OCR engine. It will return you font information as well as coordinates for the character it has recognized (note that you will most likely have to compute the actual image coordinate as the OCR engine will have deskewed the image before performing the recognition). Once you get the coordinates and the deskew so that you can compute the actual coordinate, you can then use any image manipulation library (Leadtools, Accusoft, etc) or just straight GDI+ functions to clear the character, then using the font info and size info create a new character and merge it into the image. This is not trivial but certainly doable.

Edit:
It was late when I wrote the initial answer, wanted to clarify what is meant by font information. The OCR engine will give you information regarding the point size, whether its bold/italicized and the font family (Seriph, etc). I do not know of one that will tell you the exact font that the document is in. If you have a sample of the documents that you will process, then you can make a good guess based on the info the OCR engine gives you.