Raster vs. Vector – The Document Dilemma

Understanding the Foundations of Document Imaging

Did you know that when you retrieve a file from a repository it may really be an image of the document, rather than the document itself? The accessibility of the content is the most important requirement for business documents — regardless of presentation. An entire infrastructure has developed around the need for making documents available and users more productive. Solutions for document scanning, file conversion and compression, content management, and viewing and collaboration applications are designed to give users a seamless experience.

Document types and workflow requirements are key considerations when creating your document management and viewing solution. There are two types of documents – Raster and Vector. These are not file formats but rather types of image structures. Understanding the differences between these image structures can help you maximize the value of your documents within your enterprise.

Understanding Image Structure

Raster images, or Bitmaps, are commonly thought of when describing digital imagery. In a raster image, each pixel is mapped on a grid; it has a precise location. The resolution of a raster image is measured in dots (pixels) per inch (DPI). The higher the DPI, the better the image quality – and – the larger the file size. The useful display or print size of a raster image is dependant on the resolution. Scaling the image up to a larger size may result in a loss of apparent quality  and a blurry, potentially pixilated image.

The pixels display colors individually, allowing for nuanced color variations from pixel to pixel. Depending upon the stored image format, each pixel can be controlled by up to 24 bits of color information or a total of 16-million colors. This is important for companies that require highly accurate color images in their documents.

Examples of raster image formats include TIFF, Bitmap (BMP), PNG, GIF, and JPEG.  They are typically created through a rasterizing process including faxes, scanning of paper documents, and digital cameras.

Vector images or drawings are objects created according to their geometrical characteristics (including points, lines, curves, and polygons) to represent images in computer graphics. A vector image can be scaled to any size without a loss of resolution because the geometry is adjusted as it changes. The ability to seamlessly scale makes vector the preferred choice for commonly used graphics such as logos. Every letter of text, when stored in formats like MS Word or RTF, is also a vector-based object. This allows effects such as bolding or italics to easily be added and also enables text selection, copying, or editing, character by character.

Most vector documents actually contain both vector data and raster data.  For example, a CAD drawing might contain a raster photograph.  Examples of vector and possibly raster data documents include CAD formats, Adobe PDF, and MS Office.

Documents as Images

Understanding the differences between a vector (editable document) and a raster (image of a document) can be confusing. For example, document imaging workflows typically begin with scanning paper documents, which creates a raster image, in order to compress, index, and archive. These scanned images might appear identical to a vector document when viewed by the end-user. While they may present the same information visually, raster images provide different benefits than vector documents.  

Making the choice to rasterize documents for your end users can positively impact your efficiency and productivity. Companies realize the value of raster images in a variety of situations such as:

• Facilitating high-volume, low-interaction workflows — such as verifying information — because single-page images can quickly be viewed with little bandwidth requirement.
• Ensuring document security by offering true redactions that remove pixels from a raster version of the document. The redacted material is removed from the raster image before it is sent to the end-user computer so that it cannot be undone or reverse engineered. The original document will remain secure and untouched in your file repository.
• Raster images of archived documents ensure that the content remains intact because they are difficult to change or manipulate. This enables companies to achieve compliance with federal and industry regulations.

The Evolving Raster Image

Technology for creating and displaying raster images has evolved. For many companies, paper forms are still the primary vehicle for receiving information from customers. When these documents are scanned with Optical Character Recognition (OCR), the technology can decipher the words on a page and append textual data to the raster image. This allows the data to be easily extracted and imported into a database – eliminating the need for manual entry.

Some document viewing and collaboration applications have the ability to search the text that is appended to the scanned image. As the viewer retrieves the raster image for display, the search is simultaneously performed on the original document stored on the server and the results appear on the raster image. Some viewing and collaboration applications even support page manipulation.  This enables users to quickly and easily move, copy, and delete pages, and even add annotations and redactions to the rasterized images.

These advancements effectively help organizations enhance their document workflow with functionality, speed, and security.

Master the Raster – You’ll Work Better and Faster

The difference between vector and raster means little to end users. But understanding when and how to utilize raster images within your workflow can positively impact their productivity. The choices you make in selecting complementary solutions for critical functions – including scanning, viewing, and storage – will ensure that you have an efficient and seamless workflow. Once you master the raster and bring it in to support your workflow needs, you’ll find that your end users can work more efficiently and manage documents more securely, so they’ll work better and faster.

Find out how raster and vector images affect your current workflow. Contact us to learn more about creating, viewing, and processing vector or raster images.