CODEWITHSUNDEEP
c#imagepdfitext
cookies
cookies

Reputation: 347

Skip section of PDF when extracting text and Get image coordinates

Currently, I can extract all the text chunks with their location data from a PDF. The problem is that the PDF contains images with text annotations which I do not want including in the extraction.

However, for whatever reason whenever I search the PDF for images, it only finds 1 of the images and usually throws the exception: The colour space is not supported. It's as if it doesn't recognise them as images?

I am not wishing to extract the images, just locate where they start and end in relation to the PDF so I can exempt the text that is on top of the images.

For example: enter image description here

Where the numbers on the graph are unwanted and need to be removed from the extracted text.

Im just not sure how to:

A) Locate all the images and store the coordinates of where it starts and ends

B) Ignore the text that is on top of the images in the PDF document

(I am using iTextSharp to try and achieve this, but so far I am not having much luck)

Upvotes: 1

Views: 303

Answers (1)

zenware
zenware

Reputation: 29

I'm not exactly sure how iTextSharp works but the PostScript language reference or the PDF Reference manuals may be a good place to start figuring out what you need to know.

I just cracked open a PDF file in a text editor to check out the format because I haven't seen it in a while and then realized what the problem might be.

PDFs support "Images", and "Stream Objects" which can contain image data. Stream objects actually declare enough information that you can know where they begin and end and write something to manually ignore them. A Stream Object Header looks like this:

<</Intent/RelativeColorimetric/Subtype/Image/Length 19678/Filter/DCTDecode/Name/X/Metadata 4314 0 R/BitsPerComponent 8/ColorSpace 5247 0 R/Width 290/Height 372/Type/XObject>>stream

It's entirely possible that your particular PDF has only one "Image" and then the rest of it is "Streams".

I suggest cracking it open to take a look. It would also be beneficial if you included some sample code with on the library you're using.

I also found by opening a PDF in a text editor this string /Type /Page which seems to create new pages, so you there's a chance you could count those to determine which page you're currently on.

The header at the top of the document I'm reviewing is %PDF-1.2 and the latest version is 1.7, so there may be some disparity here because of that.

Any chance you can share the PDF file you're working with?

Upvotes: 1

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