Postal barcodes have become a key element of modern logistics. They enable automatic sorting of letters and parcels, tracking of shipments, and minimizing manual labor. Below, we'll discuss the different types of postal barcodes, the challenges encountered when recognizing them, and how to recognize postal barcodes in a .NET application using
VintaSoft Barcode .NET SDK.
Why are postal barcodes needed?
A postal barcode is a machine-readable label that links a physical item to records in an information system. A single short set of bars or dots conceals data important for business and logistics.
Typically, a postal barcode is used to:
- identify a specific item in a database;
- encode the recipient's postcode or routing code;
- store information about the type of service and rate;
- link a parcel to a specific customer;
- enable tracking at sorting centers and pickup points.
Without these labels, mass processing of letters and parcels would be impossible. Proper implementation of barcode scanning directly impacts sorting speed, service quality, and operator costs.
Main types of postal barcodes
Dozens of standards are used worldwide, but to create your own scanning system, it's important to understand at least the basic groups.
Four-state postal barcodes (4-State)
This is a special class of barcodes, where each bar has one of four states of height and position relative to the baseline. Barcodes from this set of barcodes are used by major postal carriers in the US, UK, Australia, Japan, and other countries. These barcodes typically contain the sender's identifier, service type, unique item number, and routing information, while remaining relatively compact.
Linear barcodes (1D)
Many logistics and postal companies use familiar formats like Interleaved 2 of 5 (ITF), Code 128, and other one-dimensional barcodes. They are conveniently applied to stickers and shipping labels, are easily read by scanners, and are supported by almost all barcode recognition SDKs.
Two-dimensional codes (2D)
Data Matrix and QR codes are increasingly common in the postal industry. These are most commonly found on machine-paid stamps, combined postal labels, and additional stickers for enhanced tracking. 2D barcodes hold more data than linear ones and typically remain readable even when partially damaged.
In a real-world system, you may encounter any combination of these options. Therefore, the SDK you choose for your .NET application should support at least the formats used by your postal operator or logistics partner.
The challenges of recognizing postal barcodes
In theory, barcode recognition is a simple task. In practice, postal conditions make life very difficult for developers and algorithms.
The most common problems:
- poor print quality: printer streaks, smeared areas, uneven fill;
- challenging media: corrugated cardboard, glossy boxes, thin envelope paper;
- geometric distortions: folds, creases, stretched labels, tilt relative to the camera;
- partial damage: tape over the code, stickers, tears and scratches;
- poor lighting and blurring when shooting with a camera;
- multiple barcodes on one side of a parcel or envelope.
Because of these factors, relying solely on the simplest algorithms and basic settings is unacceptable. A flexible and interference-resistant engine is needed, as well as the ability to fine-tune barcode recognition parameters. This role in .NET projects can be fulfilled by
VintaSoft Barcode .NET SDK.
Hardware options for barcode scanning
Scanning postal barcodes can be based on various types of devices, and the solution architecture depends on the choice.
A common approach is to use ready-made hardware barcode scanners. These can be handheld, embedded, or stationary devices. They are fast, reliable, designed for 24/7 operation, and often can independently decode basic barcode types. However, such devices integrate less well with modern mobile and web applications, and the expansion of the supported formats is tied to the manufacturer's firmware.
An alternative approach is to use universal cameras and process the image by software. In this case, the "scanner" can be a smartphone camera, tablet camera, webcam, industrial camera on a conveyor belt, or even a standard document scanner. Barcode recognition is performed by a library embedded in the .NET application. This is exactly how the
VintaSoft Barcode .NET SDK scenario works: you control which barcodes to search for, how to process the image, and how to integrate the results into your system.
VintaSoft Barcode .NET SDK is a professional tool for barcode recognition and generation in the .NET ecosystem. The following features are particularly important for postal logistics.
First,
VintaSoft Barcode .NET SDK supports a wide range of barcodes. These include postal barcodes of four states, as well as popular linear and 2D barcodes used on envelopes, parcels, stamps, and logistics labels. This allows a single solution to handle both internal postal markings and barcodes from partner delivery services.
Secondly,
VintaSoft Barcode .NET SDK is designed to handle complex real-world images. The algorithms handle noise, tilt, imperfect printing, and small barcode sizes within the frame. This is critical when an operator films a parcel with a mobile phone or when a conveyor camera produces less-than-ideal video.
Thirdly, the developer has flexible settings available. They can specify a list of barcode types to search for, prioritize speed and quality, limit the search area to a rectangle of interest, and specify the expected number of codes in a single image. This customization helps adapt the SDK to specific sorting lines, media types, and operator workflows.
Finally,
VintaSoft Barcode .NET SDK easily integrates into various types of .NET applications. The library can be used in desktop solutions, server services, web services, and mobile applications built on modern versions of .NET. This makes it possible to build a unified barcode recognition architecture across a company's entire IT system.
Step-by-step process for scanning postal barcodes
Let's look at a typical workflow you'd implement in your .NET application using the
VintaSoft Barcode .NET SDK.
1. First, you need to obtain an image of the envelope or parcel. This could be an uploaded file, a scanned document, a separate frame from a video stream, or a photo taken with a mobile device camera. At this step, it's important to control the image size and quality to ensure the barcodes occupy a sufficient number of pixels and aren't lost when scaling.
2. Next, select a set of supported barcode types. For example, you could specify a four-state postal barcode, one or two ITF types, and a Data Matrix barcode, if that's what your carrier uses. This limitation increases speed and reduces false positives due to random patterns, textures, and artifacts.
3. Then the actual barcode recognition occurs. The application calls the VintaSoft Barcode .NET SDK API, passes an image, and receives a collection of detected barcodes. For each result, the library returns the barcode type, a string value, the coordinates of the image region, and a number of additional parameters. A single call can return multiple barcodes at once, if the image contains, for example, both a postal code and a carrier's logistics barcode.
4. The next step is analysis and validation of the received data. The string value is parsed according to the postal operator's internal format. From it, the postal code, unique shipment number, customer ID, service code, and other logical fields can be extracted. This level implements length and structure verification, database matching, check digit verification, and, if necessary, masking or encryption of sensitive data parts.
5. The final step is integrating the results with business logic. Recognized data is used to update shipment status, automatically generate routes, and record acceptance, sorting, and issuance operations. The operator interface can visually highlight the barcode area, display a detailed description, and offer a rescan if the confidence level is low.
Practical configuration recommendations
To ensure reliable and fast scanning of postal barcodes using the
VintaSoft Barcode .NET SDK, it's helpful to consider several practical points.
First, if possible, limit the list of recognized barcode formats to only actually used barcode types. This will reduce processing time and reduce the likelihood of noise or part of a logo being mistakenly interpreted as a different barcode type.
Second, carefully select the search area. If a barcode is almost always printed in a specific area of the envelope or label, define a rectangle of interest and analyze only that area. This technique is especially useful when processing large images and when working with video streams.
Third, test different speed versus quality profiles. For high-load sorting centers where throughput is critical, the SDK can be configured for maximum recognition speed, focusing on typical, undamaged barcodes. For scenarios involving legally significant shipments and a large number of problematic labels, it makes sense to enable more thorough analysis modes.
Fourth, don't forget about the shooting conditions. Even the most advanced SDK won't compensate for complete darkness or strong glare from lamps and display cases. The operator interface can include camera guidance, illumination level display, automatic zooming, and cropping of the barcode area. All this, combined with the capabilities of the
VintaSoft Barcode .NET SDK, significantly increases the final percentage of successfully read postal barcodes.
Conclusion
Scanning and analyzing postal barcodes is more than just "recognizing stripes in an image." This task involves a complex set of requirements: a variety of formats, imperfect printing and shooting conditions, high data throughput, and the need to accurately handle large volumes of data. By using a specialized .NET solution like
VintaSoft Barcode .NET SDK, you can focus on business logic and entrust the image processing, decoding, and basic validation to a proven tool. Properly configuring the SDK and thoroughly testing it on real letter and parcel samples will allow you to build a reliable system that will become the foundation for modern tracking and automation of postal logistics.
Here's some C# code demonstrating how to recognize postal barcodes in a camera image:
/// <summary>
/// Recognizes postal barcodes from a <see cref="System.Drawing.Bitmap"/>.
/// </summary>
/// <param name="bitmap">A bitmap with barcodes.</param>
public static void RecognizePostalBarcodesFromBitmap(System.Drawing.Bitmap bitmap)
{
// create barcode reader
using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
{
// specify that barcode reader must search for Postnet barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Postnet;
// specify that barcode reader must search for Planet barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Planet;
// specify that barcode reader must search for Intelligent Mail barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.IntelligentMail;
// specify that barcode reader must search for Australian Post barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.AustralianPost;
// specify that barcode reader must search for Japan Post barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.JapanPost;
// specify that barcode reader must search for Dutch KIX barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.DutchKIX;
// specify that barcode reader must search for Royal Mail barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.RoyalMail;
// specify that barcode reader must search for Royal Mail Mailmark 4-state barcode C barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Mailmark4StateC;
// specify that barcode reader must search for Royal Mail Mailmark 4-state barcode L barcodes
reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Mailmark4StateL;
// specify that barcode reader must search for Deutsche Post Identcode barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.DeutschePostIdentcodeBarcodeSymbology);
// specify that barcode reader must search for Deutsche Post Leitcode barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.DeutschePostLeitcodeBarcodeSymbology);
// specify that barcode reader must search for DHL AWB barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.DhlAwbBarcodeSymbology);
// specify that barcode reader must search for FedEx Ground 96 barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.FedExGround96BarcodeSymbology);
// specify that barcode reader must search for Italian Post 2 of 5 barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.ItalianPost2of5);
// specify that barcode reader must search for Royal Mail Mailmark CMDM Type29 2D barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.MailmarkCmdmType29BarcodeSymbology);
// specify that barcode reader must search for Royal Mail Mailmark CMDM Type7 2D barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.MailmarkCmdmType7BarcodeSymbology);
// specify that barcode reader must search for Royal Mail Mailmark CMDM Type9 2D barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.MailmarkCmdmType9BarcodeSymbology);
// specify that barcode reader must search for Swiss PostParcel barcodes
reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.SwissPostParcelBarcodeSymbology);
// read barcodes from image
Vintasoft.Barcode.IBarcodeInfo[] infos = Vintasoft.Barcode.GdiExtensions.ReadBarcodes(reader, bitmap);
// if barcodes are not detected
if (infos.Length == 0)
{
System.Console.WriteLine("No barcodes found.");
}
// if barcodes are detected
else
{
// get information about extracted barcodes
System.Console.WriteLine(string.Format("{0} barcodes found:", infos.Length));
System.Console.WriteLine();
for (int i = 0; i < infos.Length; i++)
{
Vintasoft.Barcode.IBarcodeInfo info = infos[i];
System.Console.WriteLine(string.Format("[{0}:{1}]", i + 1, info.BarcodeType));
System.Console.WriteLine(string.Format("Value: {0}", info.Value));
System.Console.WriteLine(string.Format("Region: {0}", info.Region));
System.Console.WriteLine();
}
}
}
}
