calcStepLength

This script was created to compute side specific step lengths during walks recorded via the Xsens MVN system. The computed steps will be written to csv files and visualized as bar charts. Further the script creates some diagrams: one showing the 3D positions of the feet including step positions during the recording. The others visualise velocities of the feet, the foot distance, step phase time spans and Z coordinates. Some example outputs are shown below.

Usage and argument information for R/calcStepLength:

Usage: R/calcStepLength 
	[-[-help|h]] 
	[-[-verbose|v]] 
	[-[-inputfile|i] :character:] 
	[-[-outputdir|o] :character:] 
	[-[-distepsilon|l] [:double:]] 
	[-[-velepsilon|k] [:double:]] 
	[-[-delta|d] [:integer:]] 
	[-[-min|a] [:integer:]] 
	[-[-max|b] [:integer:]] 
	[-[-colors|c] [:character:]] 
	[-[-format|f] [:character:]] 
	[-[-title|t] [:character:]]

Arguments without parameters:
  --help: show this information
  --verbose: activating informational output while parsing

Required arguments:
  --inputfile: mvnx file with 3D motion data
  --outputdir: directory to save images

Optional arguments:
  --colors: comma separated list of colors for each segment
  --delta: minimum length of a timespan [in ms]
  --distepsilon: treshold to separate distance values [in m]
  --velepsilon: treshold to separate velocity values [in m per s]
  --format: format for output, one of bmp, jpg, pdf [default], png, ps, wmf
  --min: calculate beginning at that time [in ms]
  --max: calculate ending at that time [in ms]
  --title: one title for all the diagrams
  --verbose: activating informational output while parsing

A comment on the

delta argument:: This parameter is used to remove small false positive time spans. Only time spans longer than the given delta parameter will be considered in the step length calculation. The default value is 20 milliseconds.
velepsilon argument:: This parameter is used to separate the standing foot from the moving foot. Therefore the mean values of the top 20 and low 20 percent is calculated and the middle between the two mean values is used as epsilon. You may use a personal epsilon value instead by using this optional argument.
distepsilon argument:: This parameter is used together with velepsilon to determine the standing position of a foot. The calculation is the same and you may also use a personal value with this optional argument.

Computed step lengths and diagrams for Walk05

The calculated step lengths of LeftFoot.

The calculated step lengths of RightFoot.

Comparison of absolute velocity and distance between RightFoot and LeftFoot.

Comparison of absolute velocity and Z position between RightFoot.

Comparison of absolute velocity and Z position between LeftFoot.

3D positions of RightFoot and LeftFoot together with calculated points of steps.

Calculated step lengths for LeftFoot and RightFoot.

Original call: ./calcStepLength --inputfile="../experiments/experiment1/walk05.mvnx" --outputdir="online/images/diagrams/walk05/" --format="png" --title="walk05" --colors="blue, red, green, cyan, orange, darkblue, darkred" --min="0" --max="15500"

Step Number	Segment	Begin[ms]	End[ms]	Step Length (side)
0	RightFoot	390	605	0
1	LeftFoot	1854	2300	0
2	RightFoot	3225	3531	48.7
3	LeftFoot	4507	4846	54.12
4	RightFoot	5740	6038	60.98
5	LeftFoot	6905	7292	60.99
6	RightFoot	8358	8663	60.49
7	LeftFoot	9646	10165	60.09
8	RightFoot	10941	11313	57.8
9	LeftFoot	12395	12733	55.38
10	RightFoot	13673	14003	59.97
11	LeftFoot	15001	15348	63.4

Computed steplengths from Walk05.

Computed step lengths and diagrams for Walk06

Calculated step lengths for LeftFoot and RightFoot.

Original call: ./calcStepLength --inputfile="../experiments/experiment1/walk06.mvnx" --outputdir="online/images/diagrams/walk06/" --format="png" --title="walk06" --colors="blue, red, green, cyan, orange, darkblue, darkred" --min="1500" --max="15500"

Step Number	Segment	Begin[ms]	End[ms]	Step Length (side)
0	RightFoot	2135	2325	0
1	LeftFoot	3631	4061	0
2	RightFoot	4971	5310	59.35
3	LeftFoot	6078	6434	61.28
4	RightFoot	7318	7665	67.73
5	LeftFoot	8581	8969	72.24
6	RightFoot	9894	10233	71.75
7	LeftFoot	11145	11451	71.07
8	RightFoot	12370	12651	71.83
9	LeftFoot	13620	14000	71.22
10	RightFoot	15235	15458	56.23

Computed steplengths from Walk07.

Computed step lengths and diagrams for Walk07

Calculated step lengths for LeftFoot and RightFoot.

Original call: ./calcStepLength --inputfile="../experiments/experiment1/walk07.mvnx" --outputdir="online/images/diagrams/walk07/" --format="png" --title="walk07" --colors="blue, red, green, cyan, orange, darkblue, darkred" --min="8000" --max="72000"

Step Number	Segment	Begin[ms]	End[ms]	Step Length (side)
0	RightFoot	9559	9833	0
1	LeftFoot	15173	15626	0
2	RightFoot	22926	23405	60.8
3	LeftFoot	28818	29165	61.63
4	RightFoot	35223	35794	64.99
5	LeftFoot	40531	41094	64.06
6	RightFoot	46523	47053	60.91
7	LeftFoot	51660	52362	63.76
8	RightFoot	55933	56421	62.66
9	LeftFoot	61570	62092	57
10	RightFoot	66827	67406	58.34
11	LeftFoot	71359	71855	57.57

Computed steplengths from Walk07.

Computed step lengths and diagrams for Walk10

Calculated step lengths for LeftFoot and RightFoot.

Step Number	Segment	Begin[ms]	End[ms]	Step Length (side)
0	RightFoot	2318	2517	0
1	LeftFoot	2972	3211	0
2	RightFoot	3699	3914	83.72
3	LeftFoot	4328	4559	92.7
4	RightFoot	5064	5238	98
5	LeftFoot	5635	5842	102.71
6	RightFoot	6306	6496	102.23
7	LeftFoot	6993	7200	107.78
8	RightFoot	7787	8126	105.48

Computed steplengths from Walk10.