How Do I Inspect for Circularity or Ovality of a Circle with an In-Sight Camera Using Spreadsheet?

What spreadsheet tool is best to use to inspect for circularity (ovality) of a circle?

Answer

For In‑Sight applications the most direct, built‑in solution for ovality (circularity) is the FindCircle / FindCircleMinMax sequence in your spreadsheet:

1. FindCircle
   • Use the FindCircle tool to locate and fit the nominal circle edge in your image.
   • This outputs the center and mean radius of the feature. Cognex Support FindCircle Spreadsheet
2. FindCircleMinMax
   • Insert FindCircleMinMax immediately after FindCircle.
   • It computes:
     • Minimum radius (rₘᵢₙ)
     • Maximum radius (rₘₐₓ)
     • Standard deviation of all radius samples
3. The difference (rₘₐₓ – rₘᵢₙ) or the standard deviation is your direct measure of ovality/ovality. Cognex Support FindCircleMinMax Spreadsheet

Why not Calipers?

While you could array dozens of Caliper edge‑pairs radially around the part and calculate max/min distances yourself, this is:

• Tedious to set up and tune
• Error‑prone when assemblies shift or lighting changes
• Less robust than the purpose‑built FindCircleMinMax metric

In short, go with FindCircle + FindCircleMinMax to get repeatable, high‑speed circularity/ovality data right in your In‑Sight spreadsheet.