scanned background, change to white?

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Princy557
Posts: 203
Joined: Wed May 18, 2011 10:32 am

scanned background, change to white?

Post by Princy557 »

Hi,
I have a number of scanned PDF files.
Basically, with age, these tiny books that come with some equipment is to darn small.
After going back through a few of them, it would be nice to see them with fewer grey patches.
IS it possible to clean up the background of these pages?
ACE_Head_Snap_Thursday, 11 December 2025_14h11m50s3.jpg
ACE_Head_Snap_Thursday, 11 December 2025_14h11m50s3.jpg (13.24 KiB) Viewed 4948 times

Regards
Princy557
Regards

Princy557
Jossi
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Re: scanned background, change to white?

Post by Jossi »

Hi, the file you attached is a jpg file, not a pdf. It can be opened in FlexiPDF though and it can be part of a PDF, but basically it is an image file. As FlexiPDF is not a graphics programme, you can't do image processing in FlexiPDF itself. When you choose the Object tool, then select the image and right-click, the context menu has the menu item "Image" and in the sub menu "Edit..." to open the image in your standard image editing programme and "Edit with..." to select a programme for editing. Correcting brightness, contrast and sharpness gives something like this:
ACE_Head_Snap_Thursday, 11 December 2025_14h11m50s3 corr.jpg
ACE_Head_Snap_Thursday, 11 December 2025_14h11m50s3 corr.jpg (23.1 KiB) Viewed 3241 times
Of course, if you have a great number of image files, this is a tedious procedure. It would be easier then to export all the images from a pdf and use an image editing programme with batch function to edit them all at once.
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Princy557
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Joined: Wed May 18, 2011 10:32 am

Re: scanned background, change to white?

Post by Princy557 »

Hi Jossi,
Thanks for reply
Sorry to confuse. The attachment was intended to illustrate the problem, not the actual file.
I have to go out for a few hours, I'll read your reply when I'm back.

Regards
Princy557
Regards

Princy557
raitis.veksejs
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Re: scanned background, change to white?

Post by raitis.veksejs »

I have shared the suggestion to implement a direct feature within our application to remove the gray background from scans with our developers.

In the meantime, you could use an image editor (e.g., GIMP, which is free). You can import PDF files directly into GIMP and apply thresholding (found under "Colors > Threshold").

Alternatively, using FlexiPDF's "Pages > OCR (editable text)" function will convert the page image into editable text, inherently removing the background grayness. Note that this method is best suited for pages containing simple text layouts. In your example—with a table—it won't work well with the current OCR feature's capabilities.

Also note that many scanner drivers offer features that let you handle such gray background removal. These include monochrome scan mode, despeckle (noise reduction), and brightness and contrast settings.
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Princy557
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Joined: Wed May 18, 2011 10:32 am

Re: scanned background, change to white?

Post by Princy557 »

Hi,
Thanks for that very constructive reply with the possibility of it becoming a feature.
It had gone completely over my head that I was in colour mode and will go over the scan again in monochrome.
Thanks again.
Regards
Princy557 :D
Regards

Princy557
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