Channel Inconsistency Correction in Multi-Channel Eddy Current Arrays: A Method Based on Overlapping Scans and Affine Transformation

Multi-channel eddy current arrays are widely used in nondestructive testing (NDT) for efficient surface defect measurement. However, inconsistencies between channels caused by coil fabrication tolerances and sensor tilt during scanning can degrade the accuracy and reliability of measurement results. This article proposes an adjacent-channel overlapping line measurement strategy and a data correction method based on feature point matching and affine transformation. By identifying corresponding features in overlapping scan regions, interchannel deviations can be quantitatively corrected, effectively aligning the responses of individual coils. The proposed method serves as a calibration technique to enhance measurement consistency across the array. Experimental results demonstrate its effectiveness in accurately measuring surface features of screws.