What is the difference between PDF scans and PDF/A scans? How to extract the text content of scanned documents?

 

In the digital age, we often come into contact with various types of file formats, and PDF is undoubtedly one of the most widely used among them. In the PDF family, although PDF scans and PDF/A belong to the PDF category, they have many differences. A deep understanding of the differences between them is of great guiding significance for us to correctly choose and use appropriate file formats in daily office, study, and file management scenarios. Next, let's unveil the mystery of PDF scans and PDF/A together, and explore the differences between them.

Outline

• Gain a deeper understanding of PDF scans
  • Definition and generation method of PDF scanned documents
  • Analysis of Characteristics of PDF Scanned Documents
  • Examples of application scenarios
• Comprehensive understanding of PDF/A
  • The Concept and Origin of PDF/A
  • Interpretation of Unique Features of PDF/A
  • Main application scenarios
• Summary

Gain a deeper understanding of PDF scans

Definition and generation method of PDF scanned documents

PDF scanned document, as the name suggests, is a file obtained by converting paper documents into electronic format through a scanning device, with a file extension of. pdf. The operation of generating PDF scans is very common in daily office, study, and life scenarios. We only need to place the paper material in the designated location of the scanner, then start the scanning program, and the scanner will optically scan the paper content, convert it into a digital image, and store it in PDF format in the corresponding storage device. Nowadays, in addition to professional large scanners, many multifunctional printers also have scanning functions. Even our mobile phones can easily generate PDF scans with various scanning apps such as Scan King and Quark Scan, greatly improving the convenience of scanning operations and making scanning possible anytime, anywhere.

Analysis of Characteristics of PDF Scanned Documents

From the essence of a document, a PDF scan is essentially a digital image of a paper document. It presents document content in the form of images, which means that elements such as text, charts, etc. are not truly electronic text, but are "solidified" within the image.

In terms of content editing, due to its image-based nature, it is quite difficult to directly edit the content of PDF scans. If you want to modify, delete, or add text to it, conventional word processing software is often unable to handle it. Generally, OCR (Optical Character Recognition) technology is required to first convert the text in the scanned document into editable text format before proceeding with subsequent editing. However, this process may result in inaccurate recognition and require manual proofreading.

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In terms of file size and clarity, the file size of PDF scanned documents is mainly affected by factors such as scanning resolution, document page count, and image compression level. Generally speaking, the higher the scanning resolution, the clearer the image and the larger the file size. For example, when scanning a magazine with both images and text, if a high-resolution scan is used, the generated PDF scan can clearly display every detail on the magazine, including delicate image textures and clear text, but the file size will also increase accordingly; If the resolution is reduced, although the file size will decrease, the clarity may be greatly reduced, the text may become blurry, and the image details may be lost.

In terms of security, PDF scans have a certain degree of security. It can set an open password to restrict unauthorized personnel from viewing file contents; It can also set editing permission passwords to prevent unauthorized tampering of files by others. However, compared to some file formats specifically designed for security, the security of PDF scans may be slightly inadequate in some complex scenarios.

Examples of application scenarios

In office settings, PDF scans are ubiquitous. Employees often need to scan important documents such as paper contracts, reports, invoices, etc. into PDF format for storage, transmission, and sharing on computers or mobile devices. For example, when a company's sales team signs a contract with a customer, in order for the company's legal department to review the contract content in a timely manner, the sales personnel can scan the paper contract into a PDF and quickly send it to the legal personnel via email. This not only avoids the time loss during the mailing process of paper contracts, but also facilitates legal personnel to annotate and review electronic documents.

In terms of personal file management, we also cannot do without PDF scanned copies. Many people will scan important documents such as ID cards, driver's licenses, property certificates, etc. into PDF files and save them for future use. In case of the need to provide a copy of the certificate, it is not necessary to search for the original for copying, and it is convenient and safe to print the PDF scanned copy directly from the electronic device. In addition, scanning paper photos, letters, etc. into PDF format can also facilitate long-term preservation and digital management.

Comprehensive understanding of PDF/A

The Concept and Origin of PDF/A

PDF/A is a specific format specifically designed for long-term preservation of electronic documents and is a subset of the PDF format. Its birth mainly stems from people's urgent need for long-term reliable storage of electronic documents. In the wave of digitization, a large number of electronic documents are constantly being generated. Ensuring that these documents can be accurately read and presented in the coming decades, or even longer, has become a key issue. The traditional PDF format has some limitations when facing the challenge of long-term preservation, such as font dependencies and possible loss of metadata. To address these issues, the Association of Printing, Publishing, and Conversion Technology Providers (NPES) and the Association for Information and Image Management (AIIM) have launched a new joint activity with Adobe to develop an international standard, which is the origin of PDF/A. PDF/A aims to ensure the integrity of content and consistency in presentation of electronic documents across different software, hardware, and time spans through a series of strict specifications and requirements.

Interpretation of Unique Features of PDF/A

Long term preservation is one of the core features of PDF/A. It adopts a self-contained file structure, embedding all the information required for document display, such as fonts, images, colors, etc., inside the file, greatly reducing dependence on external resources. Even if there are changes in related fonts, image resources, or software environment updates in the future, PDF/A documents can still be displayed and presented accurately and without errors. This is like a sealed box filled with supplies, where the contents remain unchanged no matter how the external environment changes, and can be opened and fully presented at any time.

In terms of content self inclusion, PDF/A has achieved the utmost. All elements in the document are fully contained within the file itself, without the need for external links or resources to supplement the display. Unlike some web documents, the content may not be fully displayed due to external image link failure, web server shutdown, and other reasons. PDF/A documents tightly 'wrap' all the necessary content within themselves, forming an independent whole.

In terms of format standardization, PDF/A has strict standards. It has made clear regulations on font embedding, color space specification, metadata requirements, and other aspects. All fonts used must be embedded in the document and must be legally embeddable fonts to ensure that the document displays text correctly on any device; In terms of color space, it must be specified in a device independent manner to ensure the consistency of document colors; At the same time, it is required that the document contains rich metadata, such as author, title, creation date, etc. These metadata provide an important basis for document management, retrieval, and understanding.

Main application scenarios

In the field of archive management, PDF/A is widely used. Government agencies, enterprises, and others choose PDF/A format in order to achieve long-term preservation and effective management of archives when processing large amounts of files. Many government departments in various countries archive important policy documents, administrative records, etc. in PDF/A format to ensure that these files can be accessed at any time in the future without any deviation in content. The electronic file format for archiving urban construction archives has been initially unified as PDF/A, fully utilizing the advantages of this format to ensure that the received urban construction electronic archives comply with relevant national confidentiality regulations.

The library industry also cannot do without PDF/A. With the advancement of digitalization, more and more libraries are beginning to digitize paper books and documents, and PDF/A format has become one of their important choices. By converting precious ancient books, academic documents, etc. into PDF/A format, it not only facilitates remote access for readers, but also effectively protects original documents, achieving long-term preservation and widespread dissemination of cultural resources.

PDF/A also plays an important role in the field of legal compliance. Legal documents often require long-term preservation and ensure the authenticity and integrity of their content. Contracts, legal documents, etc. are stored in PDF/A format, which can meet the legal requirements for long-term preservation and traceability of documents. When it comes to legal disputes, PDF/A format files can serve as reliable evidence, and their long-term preservation and content self inclusion ensure that the files can present their original and accurate content at any time.

Summary

There are significant differences between PDF scans and PDF/A in terms of format essence, content editing, storage and long-term preservation, and applicable scenarios. In daily use, we should accurately choose the appropriate file format according to our own needs. If you pursue convenient and fast temporary recording and sharing, PDF scanned copies are undoubtedly the first choice; If focusing on the long-term reliable storage and compliance management of files, PDF/A is the best choice. Only by clearly understanding the differences between the two and using them reasonably can efficient file management and circulation be achieved in digital office and life, fully leveraging the advantages of electronic documents and improving the convenience of work and life.