What Type Of PDF File Is Machine Readable?

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What type of PDF file is machine readable?

There is a very broad spectrum of different degrees of machine readability. If the PDF can be displayed at all, the machine is reading the file and rendering the content. What I think you mean by “machine readable” is better called “searchable”. It’s the level where a computer can easily, unambiguously and flawlessly extract the full text. You can test this by selecting the text, and copying it to the clipboard, then pasting it into Word or Notepad. If you get the correct content back, the PDF is searchable. But there’s an even higher degree of machine readability, and that’s called the logical content. PDF files can be tagged for logical structure. These PDFs are also known as accessible PDFs. T not only contain the text, but also the paragraphs, chapter headings, lists, list item, tables, table rows, table cells, headers, footers, table of contents, subscripts/superscripts, and a lot more. If this information is missing, the layout and structure can be ambiguous. Special artificial intelligence is required to detect the layout and the meaning, which is never 100% correct, because computers lack human level of intelligence. Sometimes even different people would disagree about where a paragraph ends, or whether a line belongs to a table/figure, or not. So if this information is missing, it can only be guessed. Then not every tagged PDF is equally complete. There are minimally tagged files, where only the most basic information is present (usually just paragraphs, or just the headers/footers, nothing else). Tables may be tagged incorrectly, so that each table row is identified as a separate paragraph. Such tagging is significantly less useful than a 100% complete logical structure. Unfortunately, it’s uncommon for PDF files to be tagged, let alone well tagged. Then the other side of the spectrum is when the text cannot even be copy-pasted via the clipboard. You either cannot select the text, or it comes out as garbage. Most people don’t notice this, because the document is perfectly readable to a human. If the pages are represented as images, then optical character recognition (OCR) is necessary before the machine can access the text. It’s similar to how people read books, by identifying edges, curves, and the shape of characters. It’s millions of times slower than reading searchable text, and it’s relatively inaccurate. You can generally accept 2–5 mistakes per page. OCR is very inefficient, in terms of cost, time and electricity consumption alike. If the text is there, just unreadable for a computer, then machines can try to match character shapes to known fonts, such as Times or Arial. The shape of each character is described by a mathematical equation called the font program. It is possible to identify each glyph based on its precise shape by comparing the subset to known font programs. Unlike OCR, this is very fast and perfectly accurate, yet I wouldn’t call this searchable, because it is not widely implemented, and if the font is not a commonly known one, we still have to fall back to OCR. As you can see, the more information is available inside the PDF, the more accurately the machine can read the content. However, even in the best imaginable case, it’s impossible to restore the original document with 100% accuracy and completeness. At the minimum, you’re losing all paragraph spacing information at the page boundaries. PDF never contains all the subtleties of the original document from which it was produced. Your best bet is to always produce an accessible PDF or PDF/A-2a, always subset embed all fonts, and never encrypt or shuffle the character codes. When security or character obfuscation is added to the PDF in order to prevent copyright violations, you’re making that file very difficult or impossible for a machine to search, extract or convert in the future. Unless the machine was somehow as intelligent as a human. Even then machines aren’t anywhere near as energy efficient as the human brain, so you want to keep text as easy to machine read as possible.

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Type on PDF: All You Need to Know

At some point in time, you may realize that the computer, which is used to access the digital file, is also a machine which is reading and rendering the PDF file. Thus, if you are looking for a way to prevent your machine from copying the PDF files to their hard drives, you don’t want to rely on a PDF or PDF/A-2a format for that, because the data inside the PDF file is becoming increasingly hard to parse. The computer can still be able to read most PDF files using only a human-readable text editor and searching tools, but at best the search will be unreliable because the document is becoming harder to parse due to the large amount of irrelevant text/meaningless information contained inside the PDF. Most people who are reading their PDFs do not realize it, because the text is not a readable text file. It’s an.

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