Improved leg tracking considering gait phase and spline-based interpolation during turning motion in walk tests

Ayanori Yorozu, Toshiki Moriguchi, Masaki Takahashi

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Falling is a common problem in the growing elderly population, and fall-risk assessment systems are needed for community-based fall prevention programs. In particular, the timed up and go test (TUG) is the clinical test most often used to evaluate elderly individual ambulatory ability in many clinical institutions or local communities. This study presents an improved leg tracking method using a laser range sensor (LRS) for a gait measurement system to evaluate the motor function in walk tests, such as the TUG. The system tracks both legs and measures the trajectory of both legs. However, both legs might be close to each other, and one leg might be hidden from the sensor. This is especially the case during the turning motion in the TUG, where the time that a leg is hidden from the LRS is longer than that during straight walking and the moving direction rapidly changes. These situations are likely to lead to false tracking and deteriorate the measurement accuracy of the leg positions. To solve these problems, a novel data association considering gait phase and a Catmull–Rom spline-based interpolation during the occlusion are proposed. From the experimental results with young people, we confirm that the proposed methods can reduce the chances of false tracking. In addition, we verify the measurement accuracy of the leg trajectory compared to a three-dimensional motion analysis system (VICON).

Original languageEnglish
Pages (from-to)22451-22472
Number of pages22
JournalSensors (Switzerland)
Issue number9
Publication statusPublished - 2015 Sept 2


  • Data association
  • Gait measurement
  • Kalman filter
  • Laser range sensor
  • Spline-based interpolation
  • Timed up and go

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Electrical and Electronic Engineering


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