METHOD FOR NON-DESTRUCTIVE TESTING OF PRODUCT QUALITY Russian patent published in 2018 - IPC G01N29/04 G01N23/83 G01N27/90 

FIELD: measuring equipment.

SUBSTANCE: surface of the monitored object is scanned with sensors of physical fields, signal values from each surface point of the monitored object are measured, range of signal values is divided by their values into I intervals, the measured signals are recorded according to their belonging to corresponding intervals, a number of measured signals in each interval is determined, difference of the number of measured signals is calculated in the subsequent and previous intervals over the entire range of values of the measured signals, as a threshold value of the radiation signal value of the physical field a value is selected from the interval for which the difference of the number of measured signals in this and the previous intervals is less than zero, and the difference of the number of measured signals in this and subsequent intervals is more than zero. It is assumed that the signal in the defective area is less than the signal in the qualitative area in quantity, the probability of false defect detection and the probability of defect skip, based on monitoring tasks. The signal quantity is measured at the center of the interval, which receives the greatest number of signals from the defective area. The signal quantity is measured at the center of the interval, which receives the greatest number of signals from the qualitative area. The number of the interval m corresponding to a value of 0.67 U^d_max, and the number of the interval n corresponding to 0.67 U^Q_max are measured. In addition, the signal is measured at the center of the interval m and at the center of the interval n. The root-mean-square value of the signal distribution in defective areas is determined. The root-mean-square value of the signal distribution in qualitative areas is determined. The ratio between the probability values of false defect detection and defect skip is set P^d_fal. and P^d_sk.. The numerical value of the threshold signal is determined by solving the reduced equation.

EFFECT: providing an opportunity to increase the reliability of defect detection and to ensure the defect detection with a given probability.

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