Image decomposition techniques such as geometric moment descriptors, Fourier descriptors, wavelet descriptors etc. have been used commercially in the fields of biometrics for finger print and iris matching, face recognition for almost over a decade. Initial test results suggest that these techniques can be used to assess the type and extent of damage in composite panels by comparing the key geometric features in the full-field displacement, strain or stress maps of damaged composites with those in the corresponding maps of undamaged composites. In this study three shape descriptors viz. Zernike moment descriptors, Fourier descriptors and wavelet descriptors will be used to represent full field stress and strain data obtained from digital image correlation and thermoelastic stress analysis for composite tensile specimens with different levels of damage and their performance will be evaluate and rated against one another. The advantages and short-comings of these three shape descriptors will be discussed together with the possibility of combining Fourier or wavelet decomposition with Zernike moments to provide a simple index of damage.