The main features of the system are piecewise linear gray level transformation, slope angle adjustment, mapping and normalization, feature distilling.
Although lumbar lordotic and sacral slope angles decreased with aging in the healthy subjects, patients with OA retained the lumbar lordotic and sacral slope angles despite progression of OA with age.
After theoretical analysis, small scale model tests are done. Two slope angles: 1:1 and 1:1.2;