Barcodes, are a key-less data entry application that facilitates automatic recognition and data collection. It originated from grocery stores and it is now used in law firms, doctors offices, retail stores, car rental returns and for security applications. The technology has been used in manufacturing companies for receiving and shipping operations for close to thirty years.bar code applications has spread to include accounting, customer service functions, warehousing, time and attendance, assembly line operation and in package delivery.
In all the application mentioned, the motivation for barcoding is to improve data management, reduce costs and to improve accessibility. The widespread adoption of barcoding has lead to the growth of many industry standards. Such standards see to it universal compliance and easy recognition of products amongst trading parties.
To discover the location of a one-dimensional barcode on a page, the computer software scans the width, over the whole height, searching for a white/black pattern of pixels. The decoding process comprises of counting and likening groups of pixel images in the area of interest. This is to determine the location of bars, relative width and white spaces between them. A specific pattern at the beginning and end of the bar-code identifies the type.
Locating and decoding a two dimensional bar-code is more complex. The process implicates locating markers, which will identify the type of barcode. These identifying features are larger blocks in three corners. The inside part of the barcode consists of white or black points that can even be made to look like a picture or logo.
Barcode Accuracy
Pixels per element
The major factor in decoding of barcodes is the number of pixels per module or per line. Decoding a large code is easy if it scanned at a high resolution. The best thing is to choose a code, which does not fill the entire page, and still does not require a high resolution that consumes a large storage space. Every time you double the resolution, the image quadruples in size. A high scanning resolution results in wastage of transmission resources and image storage. A minimum of three pixels is required for a minimum width bar in a scanned one-dimensional barcode. For two-dimensional barcodes, you should make a minimum of four to five pixels for each module.
Avoid skewed input
In many instances, a very high skew angle reduces the recognition accuracy of a barcode. If possible, you should take steps in order to reduce skew. This will involve using improved sheet fed scanners, routine maintenance, De-skewing the barcodes as separate areas of interest on a sheet or by placing an imprint on a box to aid operators to adjust manual bar code stickers. Once you have skewed images, electronic de-skew will not at all times help in improving recognition accuracy.
Variable length data
You should not allow an automatic generation of barcodes with an unlimited length data. You will be unable to guarantee an overall barcode size needed for precise recognition if many elements squashed in a fixed area. If you need variable length data, you should define a boundary to the largest size of each field. Also, test the output barcodes in an anticipated worst-case scenario for fully stuffed and damaged images.
Optimize cleanup
You should do experiments, which will determine the optimum cleanup characteristics for the different types of damage that can occur on your document. Such experiments are dilation, smooth zoom, and de-skewing the barcodes area of interest or a set of rules that try each and equates decoding confidence.
Know your image
The more you can make predictions on the images that contain barcodes, the more likelihood there is for you optimizing recognition for your image. If you know the type, number, resolution, placement of bar-codes and rotation then you are able to speed the recognition. This will also propose a lock down of your business processes to limit overall variation. The use of cues about the image will permit you to improve recognition, speed and accuracy and optimize cleanup processes.
Optimize performance
When you are processing a large number of barcodes, it is required of you to importantly increase performance. This is done by reducing scanning to either vertical or horizontal, reducing the number of codes anticipated per image, searching only the pages or locations on every page where the bar-codes are anticipated or making use of multi-threading potentiality of barcode software.
Always test your machine
You should try to simulate the anticipated business processes that your images will encounter on their route to your system. If you plan on faxing the documents twice, then you should fax sample documents at least three times. In each validation process, you should validate the output. If you copy, print or scan the documents, then you should repeat the anticipated steps twice on the worst acceptable hardware in your system.
Barcode Printers
Print volume
You should consider your daily label output. Choose a printer designed to work continuously or nonstop for 24-hour cycles.
Printer durability
Consider the type of environment the printer will encounter. Some printer designs are for rough environments and normally have sealed cabinetry to limit dust from interfering with processes. Rugged desktop printers are suitable for commercial, office and light industry work.
Print speed
Speed is a factor of throughput. Throughput is the time lapse between acknowledgement of print command and the time it takes to complete the printing process. Throughput will also depend on label formatting time. Label formatting time can cause printing delays thus affecting the print speed capability. Such delays are expensive if they happen in a production area.
Print resolution
Higher resolution is required to ease the printing of bar-codes and texts on small labels. A complex print resolution gives detailed printing of information in small areas without worsening scanner readability.
Print width of the printer
This is the widest label you are able to print. If you have an application that requires a large label like in chemical drums and shipping labels, you require a wide label printer of at least six inches in width.
Label image durability
The only alternative to long lasting, crisp images is thermal transfer. Direct thermal printers are excellent for short period applications. Direct thermal is not as long lasting as compared to thermal transfer especially when open to chemicals or direct sunlight. Varieties of direct thermal papers are limited as compared to the ones used in thermal transfer printers.
