mL DU
101
3. RESULTS
3.1 Orientation with Calibration
The results of Table 1 and Table 2 show that it is possible to measure the sit-to-standing movement for biomechanical
analysis.
Table 1. Exterior elements Table 2 Viideogrammetric mean square error
left camera right camera principal point difference and lens distortion
0.066 mm
Xo -2.097 m 3.203 m
Yo 1.052 m 0.970 m principal point difference
Zo 2.981 m 3.081 m 0.067 mm
® 0.073 0.044
$ 0.663 -0.595
0.008 0.011
3.2 Biomechanical Analysis
3.2.1 COG
In the frontal plane, the fluctuation of COG is close to the normal-side of patients. Fig. 7 shows relationship of COG,
normal-side and plegic-side knee of the serious hemiplegic patient , who cannot sit-to-stand from a chair without glasping
both her hands. Fig. 8 shows that the ratio of the distance (p) of the plegic-side knee from COG versus the distance (n)
normal-side knee. The fluctuation of a serious patient shows that the knee of the normal side is closer to COG. Also, it
indicates the inclining of COG to the normal-side.
——— moderate ---- serious
ratio
n/p
1 2 sec
Fig. 7 Distance of Knee Joint from COG Fig. 8 Ratio of Distance n versus p
3.2.2 Moment of inertia
In the sagital plane, the relationship among the position of the ankle joint, the position of the knee joint and is the
position of the hip joint is given by the equation:
tana — (Y, -Y)Z, - Z,)tanB « (, -Y)/(Z, -Z,) o
0-a-p (11)
IAPRS, Vol. 30, Part 5W1, ISPRS Intercommission Workshop “From Pixels to Sequences’, Zurich, March 22-24 1995