---
title: equationCoefficients
framework: vision
role: symbol
role_heading: Instance Property
path: vision/trajectoryobservation/equationcoefficients
---

# equationCoefficients

The coefficients of the parabolic equation.

## Declaration

```swift
let equationCoefficients: simd_float3
```

## Discussion

Discussion This equation describes the parabola on which the detected contour is traveling. The equation and the projected points get refined over time.

## See Also

### Inspecting an observation

- [detectedPoints](vision/trajectoryobservation/detectedpoints.md)
- [projectedPoints](vision/trajectoryobservation/projectedpoints.md)
- [movingAverageRadius](vision/trajectoryobservation/movingaverageradius.md)