Verification based on ISO/IEC TR 29158 (AIM DPM-1-2006)
ISO/IEC TR 29158 (AIM DPM-1-2006) is a 2D code quality verification standard designed for verifying the image quality of QR code symbols and DataMatrix symbols printed directly on products using direct part marking techniques (also known as DPM).
Direct part marking has drawn attention in industries such as aviation, automotive, electronic devices, and medical equipment to allow for product traceability. This has resulted in automatic identification codes being printed directly on products such as metal parts, metal molds, PCBs, plastic, and glass.
Among automatic identification codes, 2D codes are most often used to add a large amount of information in a limited space. Because they can contain more information than traditional 1D codes, 2D codes are used for maintaining product traceability as well as managing manufacturing processes by providing instructions or identifying parts.
As mentioned above, DPM 2D codes have grown in popularity, and are therefore more often read and used in various situations.
Because unreadable symbols have begun affecting manufacturing, some automotive manufacturers have started to control the image quality of 2D codes directly marked on parts they receive.
ISO/IEC TR 29158 (AIM DPM-1-2006), a DPM 2D code quality verification standard is used for this purpose. Employing this standard allows image specification management items to be shared comprehensively without spending time and effort reaching agreement on individual specifications.
Major differences in verification between ISO/IEC 15415 and ISO/IEC TR 29158 (AIM DPM-1-2006)
This section explains major differences in verification between ISO/IEC 15415 and ISO/IEC TR 29158 (AIM DPM-1-2006).
How the binary threshold is defined
Different methods are employed to define the threshold used to judge whether a cell is black or white.
Specifically, the following points are different.
ISO/IEC 15415 takes an intermediate value between the highest and lowest intensities in the symbol as the threshold value.
ISO/IEC TR29158 (AIM DPM-1-2006)
ISO/IEC TR 29158 (AIM DPM-1-2006) takes the intensity with the minimum total of dispersed intensities of black cells and white cells in the symbol as the threshold value.
The average intensity of black cells and that of white cells in the graph above are derived with a set threshold value and used for evaluation of cell contrast and the like.
|ISO/IEC 15415||Verification standard for 2D codes printed on labels|
|ISO/IEC TR 29158 (AIM DPM-1-2006)||Verification standard for 2D codes directly marked on products|