Description
Return a central-difference marker velocity.
Motion records combine sampled coordinates, periodic angles, event timing and signed work or impulse conventions. Local numerical differences and panels can be computed independently while actual event detection, full trajectories and physiological significance require complete measurements and analysis.
Return a central-difference marker velocity.
When to use this tool
Use Marker Velocity Central Difference Term when checking the stated movement timing, angle, geometry, energy or panel convention.
How to use the tool and how it works
- Enter beforePosition, afterPosition, stepSeconds. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read velocity. Use the output convention below.
Return a central-difference marker velocity. Require stepSeconds > 0; velocity = (afterPosition-beforePosition)/(2*stepSeconds).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| beforePosition | Before Position | Required. Finite number. |
| afterPosition | After Position | Required. Finite number. |
| stepSeconds | Time from the central sample to each neighbor; the two endpoints are separated by twice this step. | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| velocity | Velocity | Required. Finite number. |
{
"input": {
"beforePosition": 1,
"afterPosition": 1.4,
"stepSeconds": 0.1
},
"output": {
"velocity": 1.9999999999999996
}
}Limitations and assumptions
- The step is the time from the center to each neighbor, not the full separation; accuracy, noise and marker tracking are not assessed.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect calibrated motion/force data and use an appropriate complete trajectory or dynamics analysis; interpret health and safe-loading implications with qualified professionals.
References
Similar or alternative tools
- Marker Triangle Area Residual
Return planar marker-triangle area and reference residual.
- Marker Frame Condition Ratio
Return a condition number from three supplied singular values.