I am an udergradute student. A chapter of my thesis which I'm working on is an image analysis of an Enviormental Impact Assesment which I have in a PDF file. I didn't wanted to take a screenshot of every single image of the document thus I looked up for freeware that could do this for me. Luckily I found the wonderful pdfmod which allowed me to extract the images from the PDF. I selected a few pages of which I wanted to extract the images and I clicked on the option to do so. When the image extraction was finished I looked up to the output folder and to my surprise there where a lot of more files than I thought. I found this tiny size pgn's of a black background with many color dots, thus I checked other pages and notice every page of the pdf is plagued with this pgn's. I thought it was something common of pdf's but I realized it is not, I checked on other pdf's and they don't have hidden image files. I also thought it was the layers of the image but I selected a text-only page of the EIS pdf and I found still about ten of this. CAN ANY BODY TELL WHAT THIS IMAGE IS?
Note: this is a huge zoom. the original image size is 16x14 pixels. thanks.
Arcane pgn files found in PDF. Does anybody knows what they are?
Where did you get this pdf from? If it's normally behind a paywall and you downloaded for free attune it might be something to ID you in case you spread it through piracy.
this makes the most sense
It's obviously a watermark
thought so, it contains some data (or rather, it IS some data, encoded as RGB pixels)
A friend shared it to me through an usb flash dirve, he got it the same way. This EIS is an official document, nonetheless it involves a political conflict an thus it's retained.
How can I decode RGB pixels?
the picture includes the command i used (note that i edited it back to the original 16x14 size first)
Got it. Basicly the same. It only has my repository clear and those uninteligable letters and sings above. Is that encoded too? Do you think it worths my time to investigate further on that?
they don't look random/corrupted to me, so they probably mean something, but it's not obvious to me what the rest is
The first page has 49 of this. The Enviormental Impact Statement has about 360 pages. What would be the next step you would take?
idk, it seems to me like it could well have just been generated by your pdf tools, considering the fact they contain a path from your own machine in them
It's a visual programming language.
It's the Piet programming language
that would be wierd since before you extract the images pdfmod detects how many image files the pdf contains. I tried with many other PDF's, even other EIS and only in this specific PDF the tool detects this hidden images. In other cases the tool only extracts the visible images and if it detects no image files it tells you.
It seems to be a peculiar vessel to web advertising. look
you made a mistake, that's the hexdump of converts' help
Try $hexdump -C 22.3.png - convert might not be doing you any favors - if there is hidden data you might be removing it with that. Also
If it's a watermark you likely wont be able to analyze it.
mamaguevo!
Are you sure?
LUL
It's easy to try to run it through the piet compiler, but I think that dude was joking.
Not much use I think
I wanted to believe
amazing image, thanks!