Simplify the Science & Reduce CNR Check Frequency with a Pixel Value Baseline

Simplify the Science - Reduce CNR check frequency with a Pixel Value Baseline. Rational: There is a linear response between achieved CNR and corresponding Pixel Value in an automated DDA inspection system. Objective: To prove a relationship between achieved CNRPV on IQI body at technique development and an area corresponding to this PV on the casting body without an IQI in the exposure in an effort to allow Level 3’s creating techniques to complete a pre and post system check and not have IQI’s exposed during the casting inspections between those pre and post system checks. Methodology: I have completed and archived, in a production setting, hundreds of inspections with our automated DDA inspection booth. 20 PV readings have been recorded in the same 50 X 50 pixel area for 2 views of 2 separate castings with different exposure ranges. Results: Results showed PV’s to be within a +- 15% PV range from the technique baseline values determined from first technique approved. Major Conclusion: If PV’s are initially measured on IQI body and CNR of 2.5 or greater has been achieved under the same exposure calibration conditions it can be argued that an area of a casting reading the same PV’s has achieved CNR without IQI present in the exposure.

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