Returns the radial distortion calibration data for a Sigma 8mm f/3.5 EX DG circular fisheye lens. This calibration maps normalized image radius to elevation angle.
Value
A list with two components:
- radius
Normalized radial distance from image center (0 to 1)
- elevation
Elevation angle in radians (0 at horizon, pi/2 at zenith)
A list with components radius (normalized image radius),
elevation (elevation angle in radians), and name (lens
identifier for this calibration; currently "sigma8mm").