Detection system and method of detecting corrosion under an outer protective layer

A detection system identifying structural anomalies in a substrate covered by a layer or coating, the detection system comprising:

• an imaging system including a detector configured to receive and detect, in use, reflectivity from a substrate under test, said reflectivity arising from illumination of the substrate by an incoherent, wide-angled source of electromagnetic waves, the detector configured to observe reflectivity within frequency bands that are transparent with respect to atmospheric water and atmospheric oxygen;
• an active incoherent noise source providing, in use, selective wide-angled illumination of the substrate under investigation, the active incoherent noise source generating at least one of (i) millimeter wavelengths, (ii) sub-millimeter wavelengths and (iii) micron wavelength having a frequency below about thirty terahertz;
• and
• a processor-based evaluation system responsive to the imaging system, the processor based evaluation system configured to present an indication of a difference in detected reflectivity between at least one of:
• reflectivity evaluated from a plurality of different areas of the substrate, whereby the difference in reflectivity indicates an anomaly, and
• observed reflectivity of an area of the substrate under test against a reference reflectivity value anticipated for the area of the substrate under test, whereby the difference in observed reflectivity relative to the reference reflectivity indicates an anomaly;
• wherein the processor-based evaluation system being further configured to contrast relative levels of reflectivity from the substrate as produced by said active incoherent noise source and said passive source, and generate an indication of the presence of an anomaly in the substrate in the event that the contrast of measurable parameters for evaluated reflectivity under the active and passive sources yields a difference that exceeds a predetermined threshold.

A detection system identifying structural anomalies in a substrate covered by a layer or coating, the detection system comprising:

• an imaging system including a detector configured to receive and detect, in use, reflectivity from a substrate under test, said reflectivity arising from illumination of the substrate by an incoherent, wide-angled source of electromagnetic waves, the detector configured to observe reflectivity within frequency bands that are transparent with respect to atmospheric water and atmospheric oxygen;
• a processor-based evaluation system responsive to the imaging system, the processor-based evaluation system configured to present an indication of a difference in detected reflectivity between at least one of:
• reflectivity evaluated from a plurality of different areas of the substrate, whereby the difference in reflectivity indicates an anomaly, and
• observed reflectivity of an area of the substrate under test against a reference reflectivity value anticipated for the area of the substrate under test, whereby the difference in observed reflectivity relative to the reference reflectivity indicates an anomaly;
• and
• an active incoherent noise source providing, in use, selective wide-angled illumination of the substrate under investigation, the active incoherent noise source generating at least one of (i) millimeter wavelengths, (ii) sub-millimeter wavelengths and (iii) micron wavelength having a frequency below about thirty terahertz;
• wherein the processor-based evaluation system is further configured to provide an indication of confidence in structural integrity of a layer on, or coating covering, the substrate under test, the indication based on evaluating transmissivity through the layer or coating, the evaluation contrasting differences in the spectral reflectivity profiles observed using the passive source and the active source.