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. 2006 Sep 15;3:15. doi: 10.1186/1742-9994-3-15

Table 5.

CVA results using variable number of semi-landmark points used.

Cross-validation assignment rate (%)

Data acquisition Data processing # of points used # of PC axes Observed 95% confidence interval
Curve tracing Bending energy 20 18 67.4 67.4 – 93.5
Curve tracing Bending energy 30 18 78.3 67.4 – 93.5
Curve tracing Bending energy 41 10 84.8 73.9 – 95.7
Curve tracing Bending energy 60 10 84.8 69.6 – 95.7
Curve tracing Bending energy 82 9 87.0 69.6 – 95.7
Curve tracing Bending energy 120 9 87.0 67.4 – 95.7
Curve tracing Perpendicular projection 20 18 84.8 76.1 – 97.8
Curve tracing Perpendicular projection 30 10 82.6 76.1 – 95.7
Curve tracing Perpendicular projection 41 11 84.8 71.7 – 95.7
Curve tracing Perpendicular projection 60 13 87.0 73.9 – 97.8
Curve tracing Perpendicular projection 82 13 84.8 76.1 – 97.8
Curve tracing Perpendicular projection 120 12 84.8 76.1 – 95.7
Curve tracing Elliptical Fourier analysis 41 10 84.8 65.2 – 93.5
Curve tracing Elliptical Fourier analysis 82 12 73.9 63.0 – 93.5
Fan Bending energy 41 6 89.1 73.9 – 95.7
Fan Bending energy 82 7 89.1 76.1 – 95.7
Fan Perpendicular projection 41 9 87.0 73.9 – 97.8
Fan Perpendicular projection 82 7 89.1 78.3 – 97.8

The rate of correct cross validation assignment based on the canonical variates analysis (CVA) was not highly dependent on the number of points used to represent the curve. The number of principal component (PC) axes used to optimize the cross-validation assignment rate varied with the data acquisition and processing methods and the number of points on the outline.