Support - Accuracy

  1. What is calibration and why is it important?
    Calibration is the process of determining the numerical relationship between the observed sensor output (i.e. ADC output voltage) and the known value of pressure being applied to the particular sensor. The Stepscan® Tile is considered calibrated if its pressure measurements are within a predetermined range of the known applied pressure. The system must be carefully calibrated to obtain the best results in terms of accuracy and repeatability for the end user. The accuracy and repeatability of measurements obtained on a PMD will vary among levels of applied pressure, calibration procedure, duration of pressure application, frequency of pressure application (i.e. static or dynamic), contact surface compliance/elasticity, contact surface shape (i.e. flat or curved), previous loading history, etc. calibration should be performed under conditions that are as close as possible to the actual measurement conditions.
  2. Does the system come calibrated?
    Yes, each of the 14,400 sensors of the Stepscan® Tile Unit is individually calibrated across the entire pressure range before being delivered to the end user.
  3. How accurate is the Stepscan® device?
    Accuracy;  Hysteresis ≥95%
  4. Does it need to be calibrated and how often?
    Each of the 14,400 sensors of a Stepscan® Tile Unit are individually calibrated across the entire pressure range in-factory before being delivered to the customer.  It is recommended that the system be calibrated at least once a year.  The customer can check the calibration accuracy on site using our COP (Center of Pressure) device available with the sale of the Stepscan® system.
  5. Can I calibrate the tile?  How will they know if the calibration is correct?
    The end user cannot calibrate the tile.  To ensure the highest standard of accuracy the tile is in-factory calibrated after manufacturing.  The customer can verify if the calibration is correct using a COP (Center of Pressure) device and do on-site periodic assessment of the accuracy of COP, as well as local load and mean pressure under the COP feet. If the calibration is not optimized, the tile must be returned to ViTRAK’s  head office for in-factory recalibration.
  6. What control parameters are in place to ensure the quality of the performance of the Stepscan® Tiles?
    On a select number of Tiles we have developed Standard Operating Procedures to test for the following technical parameters.
    • Pressure Distribution
    • Hysteresis
    • Creep
    • COP
    • Cross-Talk
    • Accuracy after fatigue
    • Bandwidth


    The results of these tests are compared with i-FAB standards to assess the floor tiles functionality. The equipment used to perform these tests is the same as that is used to calibrate the tiles.

  7. How does the instrument scan/the sensors scan? Is the scanning a snapshot with all 14,400 firing simultaneously or are the sensors sequentially scanning?
    Each tile is composed of four quarter tiles, with 60 rows of 60 sensors each (3600 sensors total).  For each image, the quarter tile scans through its sensors, one row of 60 sensors at a time, but very rapidly (<100us per row).  Each of the quarter tiles perform this process independently and send the data to a central processor in the tile, which combines them and forwards the full-tile data to the Stepscan® Software application.  This application combines and synchronizes data from multiple tiles to give multi-tile images, where the sensor data is collected within the same time slice (e.g., 10ms for 100Hz sampling rate).

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