1.2.2.9: Optical Scanners and Readers

Optical scanners and readers

There are a number of different optical scanner technologies on the market.

• Optical Scanners use light-emitting devices to illuminate the printing on paper. Depending on how much light is reflected, a light-sensor determines the position and darkness (or color) of the markings on the paper. Special-purpose optical scanners are in use by postal services to read and / interpret hand-written postal codes. General-purpose scanners are used with personal computers to scan in images or text. These vary from handheld devices (see picture) to flatbed scanners which feed input documents one sheet at a time. A common use of optical scanners is the scanning of black-and-white or color images and pictures. When scanning text, it is necessary to load additional optical character recognition (OCR) software that converts the scanned raster-image of the text into the equivalent character symbols, so that they can be edited using word processing software.
• Barcode scanners detect sequences of vertical lines of different widths, the ubiquitous barcode as found also on the back of this book. These scanners have become very popular with retailers due to the fact that all pre-packaged products are now required to have a product bar code on their packaging, following the standard laid down by the South African Article Numbering Association (SAANA). Libraries and video shops now also commonly use bar code scanners. They are more generally used for tracking and routing large numbers of physical items such as for asset inventory purposes in many larger organizations, postal items by the postal services and courier services, or for luggage handling by airlines.
• Optical mark readers are capable of reading dark marks on specially designed forms. The red multiple choice answer sheets in use at many educational and testing institutions are a good example.

• Let's apply an agricultural perspective to the various optical scanner technologies:

   

  1. Optical Scanners:

  General Optical Scanners: Think of general-purpose optical scanners as the versatile agricultural tools used for multiple tasks, like a multifunctional tractor. Just as a tractor can plow, plant, and harvest, general optical scanners can handle a variety of tasks, from scanning images to text. These scanners come in different forms:

  • Handheld Scanners: Similar to hand tools like a hand hoe or a pruning shear, handheld scanners are portable and used for smaller, more specific tasks—like scanning a single page or a small label.
  • Flatbed Scanners: These are akin to larger, more comprehensive farm equipment like a combine harvester. They handle larger documents or multiple pages at a time, much like how a combine harvester manages extensive harvesting tasks efficiently.

   

  2. Special-Purpose Optical Scanners:

  Postal Code Readers: These are similar to specialized agricultural machinery designed for niche tasks. For example, just as a soil moisture sensor is used to monitor specific soil conditions, postal code readers are designed to interpret specific types of information (handwritten postal codes). They help streamline and automate processes, similar to how a precision farming tool enhances specific aspects of agricultural operations.

   

  3. Barcode Scanners:

  Retail and Inventory Management: Barcode scanners are like the efficient inventory systems used in large-scale farming operations. Just as a farmer might use a computerized system to track and manage crops, livestock, or equipment, barcode scanners are used to track products in retail, libraries, or warehouses. These scanners read barcodes—comparable to how a farmer might catalog produce with specific identifiers to keep track of inventory or streamline distribution.

   

  4. Optical Mark Readers:

  Mark Readers for Forms: Optical mark readers are similar to specialized agricultural tools used for particular data collection tasks, such as soil testing equipment that reads specific measurements from samples. Optical mark readers efficiently process multiple-choice answer sheets or other forms with marked selections, much like how specific agricultural tools quickly process certain types of data or conditions.

   

  5. OCR Software Integration:

  Text Recognition and Data Conversion: Optical Character Recognition (OCR) software, used to convert scanned text into editable format, can be compared to sophisticated farm management software that interprets data from various inputs (like weather stations or crop sensors). Just as OCR software makes text editable and usable, farm management systems turn raw data into actionable insights, helping farmers make informed decisions based on comprehensive data analysis.

   

  6. Overall Technology Use:

  In agriculture, as with optical scanners, the choice of technology is often based on the specific needs of the task at hand. Whether it's a general-purpose tool, a specialized piece of equipment, or a system designed to handle specific data inputs, each piece of technology serves to enhance efficiency and accuracy in its respective field.

  In summary, optical scanner technologies, when viewed through an agricultural lens, can be seen as specialized and versatile tools that help streamline and improve various processes, much like the diverse equipment used in farming to handle different tasks efficiently.