Barcode grade: we are not achieving the quality of barcode required

Ensure the minimum pass grade for barcodes is set accurately - in Perceptor IoT, the grades are from 0.0 to 4.0.

Barcode grading evaluates the print quality of barcodes and, in Perceptor IoT, we assign a score ranging from 'fail' 0.0 to 'excellent' 4.0.

(Note that some grading uses the range A to F.)

Grading measures parameters including reflectance, edge contrast, print defects and height to ensure the barcode can be scanned reliably.