What is a machine-readable code?
A machine-readable code represents information in a form that a computer or sensor can capture and process without a person having to read and enter the data manually. In production-line identification, common examples include one-dimensional barcodes and two-dimensional codes such as DataMatrix and QR Code.
NIST uses the broader term machine-readable for data that can be processed by a computer without human intervention while preserving its semantic meaning. In industrial identification, the printed or marked code acts as the data carrier that allows this information to move from the physical product or pack into a computer system.
Readability describes whether equipment can capture and decode the code. It does not, by itself, mean that the symbol has passed formal barcode verification.
At a glance:
- Machine-readable codes carry information in a pattern designed for automatic capture and computer processing.
- Common production-line examples include linear barcodes, DataMatrix codes and QR codes, depending on the identification requirement.
- Barcode readers and imaging systems capture the symbol and decode the information represented by its pattern.
- Code verification is a separate quality process and should not be treated as another name for successful code reading.
Machine-readable code examples in printing and marking
Barcodes are a common form of machine-readable code. GS1 describes a barcode as a machine-readable representation of information using graphical patterns that optical readers or suitable software can capture.
Linear or one-dimensional barcodes represent information using bars and spaces. Two-dimensional codes use patterns arranged across two dimensions and can carry more information within the symbol.
Examples relevant to industrial identification include:
- Linear barcodes, such as GS1-128 and other one-dimensional formats used for automatic identification and data capture.
- DataMatrix codes, which use a matrix of light and dark elements and are read with imaging equipment.
- QR codes, another two-dimensional format that can encode information for machine processing.
Choosing the right machine-readable code
The appropriate format depends on the application and the data standard being used. A machine-readable code is therefore a broader concept than any single barcode symbology.
The term can also have a different meaning in software and data-management contexts. In this glossary, it refers specifically to codes printed or marked on products, labels or packaging for automatic identification rather than programming instructions or source code.
For production-line applications, ALS Identify supplies vision systems for code reading as well as barcode-scanning equipment.
What information can a machine-readable code carry?
The code is the carrier; the information encoded inside it is a separate consideration.
In a GS1 identification environment, a machine-readable code can carry an identification key and, depending on the barcode type and application, additional information such as a batch or lot number, expiry date, or serial number.
This distinction matters when specifying an identification system. Choosing a barcode format does not, on its own, define the information that needs to be captured. The production requirement should first establish which data fields are needed and how the receiving system will use them.
For example, one application may only require a product identifier. Another may need an identifier together with batch or serial information for a traceability process. The reader must be able to recognise the selected code type and pass the decoded information to the relevant system or control process.
Machine-readable coding, therefore, involves both the physical data carrier and the structure of the information encoded within it.
How is machine-readable code read in production-line identification?
Reading a machine-readable code involves capturing the symbol and decoding the pattern into usable data.
GS1 describes these as two related stages. First, the reading device captures the graphical pattern. The decoder then interprets that captured information to determine the data encoded in the symbol. Once decoded, the information can be passed to another system for processing.
Different code formats can require different barcode-reading equipment. Linear codes can be supported by suitable linear or imaging scanners, while two-dimensional symbols, such as DataMatrix, require imaging-based reading because information is encoded across both dimensions of the symbol.
Equipment selection for machine-readable codes
ALS Identify’s current identification range includes handheld scanners, fixed-mount barcode scanners, and industrial code readers. The equipment choice should therefore follow the actual identification requirement rather than treating every machine-readable code as the same scanning task.
When defining the requirement, establish:
- The code format that needs to be read
- The information that must be captured
- Whether the selected reader supports that code type
- Whether reading alone is sufficient
- Whether a separate verification requirement also applies
Keeping these points distinct makes it easier to specify the identification function before choosing the equipment.
Machine-readable code vs code verification
Machine-readable code and code verification describe different parts of an identification process.
Machine-readable code: the data carrier
The machine-readable code is the graphical representation that carries encoded information. Its job is to present the data in a form suitable equipment can capture and decode.
A successful read means the reader obtained usable information from the symbol. That result is important for the identification process, but it does not automatically provide a formal assessment of the symbol’s print quality.
Code verification: assessing barcode quality
Barcode verification is a separate process used to assess the quality of a printed barcode against the applicable barcode standards.
GS1 distinguishes ordinary reading from formal verification and states that GS1 DataMatrix verification requires an ISO/IEC-compliant verifier. Verification can assess whether the printed symbol meets defined quality requirements rather than simply whether one particular reader managed to decode it.
This distinction is important because a barcode can be readable by a scanner in a particular situation without having undergone formal verification.
Define the required identification outcome
Production teams should therefore define the required outcome clearly. If the need is to capture encoded data for an identification workflow, the requirement is code reading. If the process also requires a formal assessment of barcode quality, verification should be specified separately.
Where inspection extends to label presence, code readability, date or batch codes and other pack checks, vision inspection systems can form part of the wider quality-control process.
Why code format and reader capability need to match
A machine-readable code only becomes useful to an automated process when the selected equipment can capture and decode the chosen format.
This is particularly relevant when moving between linear and two-dimensional codes. A reader designed around one scanning method may not necessarily support every data carrier used on the line. GS1 guidance, for example, notes that two-dimensional symbols require imaging capability.
The code format, reader capability, and required data should therefore be considered as one identification requirement. This prevents a project from focusing on the visible presence of a barcode while overlooking whether the equipment can actually decode the required symbol and pass the information into the production process.
Where code quality also needs to be assessed, that verification function should then be added as a separate requirement rather than assumed from the scanner’s ability to read the code.
ALS Identify barcode readers for machine-readable codes
ALS Identify supplies identification systems covering barcode scanners, industrial code readers, and vision equipment for production-line identification.
Start by defining the code format and information that the production process needs to capture. The team can then assess the appropriate reading equipment and whether the wider application also needs a separate code-verification function. Contact ALS Identify to discuss the identification requirement for your production line.
