Fractional Grading

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## Interpretation of results - Fractional grading (continuous grading)

Here is the table that shows how the 2016 release of the standard converts the parameter percentages into grades. These percentages are rounded to the nearest integer.

The last three parameters in this table are unchanged, as they are pass or fail. The symbol must be able to be decoded, the minimum reflectance must be less than or equal to half of the maximum reflectance, and the minimum edge contrast must be greater than or equal to 15%.

This table shows how percentages for the different parameters were changed into integer values following the 2000 approach.

This approach has meant that a symbol that has, say, consistent symbol contrast values of 67% to 69% [with all other parameters being 4) would have ten grades of 3 to be averaged, so an overall score of 3.0.

The four graphs below show how particular integer percentage values for the different parameters are converted into grades to one decimal place.

Grade Symbol contrast Modulation Decodability Defects Decode Minimum reflectance Minimum edge contrast
4 ≥ 70% ≥ 70% ≥ 62% ≤ 15% Pass ≤ RMax/2 ≥ 15%
3 ≥ 55% ≥ 60% ≥ 50% ≤ 20%
2 ≥ 40% ≥ 50% ≥ 37% ≤ 25%
1 ≥ 20% ≥ 40% ≥ 25% ≤ 30%
0 < 20% < 40% < 25% > 30% Fail > RMax/2 < 15%
Grade Symbol contrast Modulation Decodability Defects Decode Rmax/Rmin Minimum edge contrast
4.0 ≥ 70% ≥ 70% ≥ 62% ≤ 15% Pass ≥ 2 ≥ 15%
3.0 to 3.9 55% to 69% 60% to 69% 50% to 61% 16% to 20%
2.0 to 2.9 39% to 54% 50% to 59% 37% to 49% 21% to 29%
1.0 to 1.9 20% to 38% 40% to 49% 25% to 36% 26% to 30%
0.1 to 0.9 15% to 19% 30% to 39% 20% to 24% N/A
0.0 < 15% < 30% < 20% > 30% Fail < 2 < 15%

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