# Theory

This section explains the theoretical foundations and implementation details of PyFlowReg's variational optical flow approach.

## Parameter Guide

Understanding and configuring the key parameters:

- **[Diffusion Parameters](parameters.md#diffusion-parameters)** - a_smooth and a_data explained
- **[Spatial-Temporal Filtering](parameters.md#spatial-temporal-filtering-sigma)** - 3D Gaussian filtering with sigma

```{toctree}
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parameters
```