  The inner surface of superconducting cavities plays a crucial role to achieve
highest accelerating fields and low losses. For an investigation of this inner
surface of more than 100 cavities within the cavity fabrication for the
European XFEL and the ILC HiGrade Research Project, an optical inspection robot
OBACHT was constructed. To analyze up to 2325 images per cavity, an image
processing and analysis code was developed and new variables to describe the
cavity surface were obtained. The accuracy of this code is up to 97% and the
PPV 99% within the resolution of 15.63 $\mu \mathrm{m}$. The optical obtained
surface roughness is in agreement with standard profilometric methods. The
image analysis algorithm identified and quantified vendor specific fabrication
properties as the electron beam welding speed and the different surface
roughness due to the different chemical treatments. In addition, a correlation
of $\rho = -0.93$ with a significance of $6\,\sigma$ between an obtained
surface variable and the maximal accelerating field was found.
