Patent ID: 11954845
Assignee: AIRBUS SAS
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. A system configured for carrying out a method for determining striation properties of fatigue striations on a sample surface of a part, the system comprising a scanning microscope device configured for imaging the sample surface to obtain a sample image potentially containing the fatigue striations and a data processing apparatus having:
an image patch selecting device configured for selecting a sample image patch potentially containing the fatigue striations from the sample image;
a pre-processing device configured for:
normalizing the sample image patch by performing, on the sample image patch, any of:
a Gaussian filter operation; and/or
a histogram equalization; and/or
an image binarization and subsequent morphological operation, such as including erosion, dilation or skeleton-operations; and/or
a frequency domain self-filtering operation; and/or
a window operation or applying a Hamm window; and/or
a normalization operation to normalize intensity values to a fixed range; and

enhancing line-like regular structures contained in the sample image patch to obtain a normalized image patch;

an autocorrelation device configured for determining an autocorrelation of the normalized image patch to obtain an autocorrelation image patch;
a Radon transform device configured for performing a Radon transform of the autocorrelation image patch to obtain a transformed image patch;
a frequency analysis device configured for performing a spectral analysis of the transformed image patch and determining a power spectrum of the transformed image patch;
a striation property determining device configured for determining, from the power spectrum, at least one striation property that is suitable to indicate a presence of fatigue striations in the sample image patch; and
a fatigue damage determining device configured for determining, if a peak in the power spectrum exceeds a predetermined threshold, that the part suffers from fatigue damage, and determining, if the peak does not exceed the predetermined threshold, that the part does not suffer from fatigue damage.