Overview
When connected with Cesium, the rendering from VSAR can be altered to simulate the real lens distortion.
Lens Distortion Modes
There’s multiple ways to model the lens distortion, VSAR simulates radial distortion with the following modes:
- “Radii Array”, an array of radii (pair of source radius and destination radius, up to 10 pairs).
- “K3 Coefficients” (default), a polynomial representation of radial distortions where:
rsrc = rd*(1+k1.rd^2+k2.rd^4)- rsrc: source radius ie. undistorted radius
- rd: distorted radius
- k1,k2,k3: radial distortion coefficients
This model is used by Stype for example and is more precise than “Radii Array”.
To enable lens distortion, select a CesiumCamera and check the box “Enabled” in the “Lens Distortion” menu.
The mode is automatically selected depending on the data received from Cesium. To force a specific mode, check the box “Mode” then select one mode in the drop down list:
Image description: No distortion
Image description: Barrel Distortion simulated (Exaggerated for visualization) with no extra focal
Auto extra focal
VSAR automatically computes and applies an extra focal multiplier (overscan factor) needed to calculate the area “outside” the distorted render. This removes “bleeding edges” on the final output.
| Note: On severe lens distortion, this setting can introduce blurriness as the rendering is upscaled. |
To force a specific extra focal multiplier value, check the box “Extra Focal Multiplier”, then input a value (example: a value of 1.0 will cancel the extra focal effect).
Image description: “Bleeding edges” removed, the blurriness is only noticeable with heavy distortion (Exaggerated for visualization)