Distortion Correction Theory

Basic Types of Distortion

There are two basic distortions that happen when using a VR headset.

_images/Barrel_distortion.png Barrel distortion
_images/Pincushion_distortion.png Pincushion distortion

Basic Formula for Software Correction

For a normal image, we can change the position of each point by using the formula:

_images/DistortionFormula_WVR.png _images/DistortionFormula_1.png _images/DistortionFormula_2.png _images/DistortionFormula_3.png

The offset of K must be set as 0 currently for SDK algorithm. The rest of the coefficients K can refer to Brown distortion model and rely on further fine-tuning. The value of K depends on the effect you want to achieve. For example, a negative K value will produce a barrel distortion, while a positive K value will produce a pincushion distortion.

Distortion Correction in the VR Environment

To correct a pincushion distortion image, apply a barrel distortion to make the image look normal. VR headsets produce a pincushion distortion when looking through the lens. To correct this, apply a barrel distortion to make the image look normal. Finding the correct value of K is the most important thing when correcting distortion.

Reference:Wiki