I badly needed help (optical motion analysis software)

good day everyone!

I am an ECE student who's currently taking my thesis 1..
We found a journal titled "Imitation Control for Biped Robot Using Wearable Motion Sensor" in which they use commercial
optical motion analysis system Hi-DCam (NAC image
technology. Japan) to validate the wearable motion analysis system’
performance and compare the results from the wearable
system with the measurements.

What I would like to ask is if anyone of you knows an alternative for this optical analysis motion system that has the same function with the Hi-DCam that has lower cost.
or
if anyone of you knows a software that do the same function with the Hi-DCam..

thank you and God Bless us all..