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Rendering character

Posted: Mon Dec 17, 2012 9:47 am
by Urvish
Hi,

i am using gdpicture versin 9.0.
i am unable to recognize character with blur and dotted background in my pdf.
can u please suggest me wht to do?

Re: Rendering character

Posted: Tue Dec 18, 2012 1:42 pm
by Loïc
Hello,

Could you attach an image as example?

Kind regards,

Loïc

Re: Rendering character

Posted: Wed Dec 19, 2012 8:31 am
by Urvish
Hi,
I have attach my image

Thanks,
Urvish

Re: Rendering character

Posted: Sat Dec 22, 2012 1:58 pm
by Loïc
Hello,

Unfortunately there is definitively nothing we can do to correctly OCR such image.

Kind regards,

Loïc

Re: Rendering character

Posted: Mon Dec 24, 2012 8:30 am
by Urvish
Hi,

Thank u very much loic for ur reply.
is ther any other way if u can suggest me?

Kind regards,
Urvish

Re: Rendering character

Posted: Mon Dec 24, 2012 12:15 pm
by Loïc
Hello Urvish,

The better quality I've been able to obtain is by combining upscalling and adaptive threshold in this way:

Code: Select all

GdPictureImaging.Scale(ImageID, 1000, Drawing2D.InterpolationMode.HighQualityBicubic)
GdPictureImaging.ConvertTo1BppAT(ImageID, 30)

Unfortunately, this is probably not enough for OCR purpose. There is 3 major issues with your image:

- It has been produced in low resolution.
- The background can not be correctly extracted from the foreground. I've tried many pre-filtering plus all existing adaptive thresholding mechanism with no success.
- It is almost impossible to recover all characters contours. This is due to the background pattern which has the same luminosity and saturation as the chars.

Basically an extreme solution would consist to write an algorithm, dedicated for this kind of image, that would be able to remove the background pattern, rebuild the characters contours and threshold the result to a highest resolution bitmap. If you are able to write such function, new problem will come: You will not find any OCR engine that will be able to provide accurate result on your bitmap since the produced characters will contain too much variation.

I am maybe wrong, but based on my experience on similar challenges (my job for 6 years), I don't see any suitable procedure to provide accurate results without a checksum mechanism or a database containing all possible occurrence plus an ICR engine providing a voting mechanism.

With best regards,

Loïc

Re: Rendering character

Posted: Mon Dec 24, 2012 12:50 pm
by Urvish
Hi,

Thank you very much loic for your suggestions and fast reply.

Thanks,
Urvish

Re: Rendering character

Posted: Tue Dec 25, 2012 1:48 pm
by Loïc
You're welcome! :)

Re: Rendering character

Posted: Tue Jan 01, 2013 8:41 am
by Urvish
Hi Loic,

I am using GdPicture Version 9.0
I want to create new pdf from my existing pdf.
Iwant to render all the text and image from it and write it to new pdf file.
how can i create it using gdpicture?
can u help me out for this?


Thanks,
Urvish

Re: Rendering character

Posted: Wed Jan 02, 2013 4:02 pm
by Loïc
Hello Urvish,

Please try to create a standalone ticket into the appropriated subforum for any new request.

Thank you for your understanding.

With best regards,

Loïc

Re: Rendering character

Posted: Mon Jan 07, 2013 8:05 am
by Urvish
Hi,

Ok.
No Problem.

Thanks,
Urvish