Most of previous study about joint kinematic analysis using X-ray image needed total clear outline of bones. However, to obtain the clear outline is not easy in clinical because X-ray image of knee often overlaps with bones. In this study, the method of kinetic analysis that uses the outline, which was not totally clear, was proposed. In order to achieve the aim, P type Fourier Descriptor that can be used in an open curve was applied. And, using feature vectors which were based on shape feature, initial point and terminal point of the outline, the library data base preliminary selected. After, an outline of the object was divided in three parts, template pattern matching was performed. In results, the standard deviation of errors of patella were θx=1.00±0.84 deg, θy=0.55±0.65deg, θz=0.62±0.12deg. And, the standard deviation of errors of cervical vertebra were θx=0.36±0.11 deg, θy=0.84±0.38deg, θz=0.72±0.25deg. The accuracy of patella was lower than that of cervical vertebra. Spectrums depend on estimation of 3D kinetic.
