The QR Code Is Not Found by NI Vision Assistant

Updated May 19, 2020

Issue Details

I'm developing QR code reader using NI Vision Assistant. When I try to detect my QR code, there is no error occurred but there is not found message like below.

Code Read:
2D barcode not found


This QR code could be detected by my phone and some tools. And also there are some tools that cannot detect this code.
Why can't NI Vision Assistant find this QR code?

Solution

At the Settings tab, you could use Suggest Values to adjust the parameters for searching.

If you still cannot detect QR, you have to check whether your QR code complies with QR code standard or not. Even though the QR code works with one tools does not mean the quality is good enough to work with all QR software.

The following factors can cause errors in the search and decoding phases or 2D code recognition: 

  • Very low resolution of the image. 
  • Very high horizontal or vertical light drift. 
  • Contrast along the bars of the image. 
  • High level of noise or blurring. 
  • Inconsistent printing or stamping techniques, such as misaligned code elements, inconsistent element size, or elements with inconsistent borders. 
  • In PDF417 codes, a quiet zone that is too small or contains too much noise. 

Additional Information

The Suggest Values button suggests a value for the parameters based on the image currently loaded in the Processing window. The purpose of the Suggest Values button is to recommend parameter values that may increase the reading speed of the step. However, if you expect the parameter values of the barcodes in your application to vary, select the Auto-detect option when available. When the Auto-detect option is selected for a given parameter, the 2D Barcode Reader step automatically detects the value for that parameter during run time.