# VF Inverse CLP

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## General Information

- Type: CLP
- Category: VectorField
- Author: Nicolas Duchateau
- Contributor: Xavi Planes
- Contact: xavier.planes at upf.edu
- Description: Compute the inverse of a vector field. This is a gradient descent approach based on the definition of the vector field inverse gradient defined in Arsigny et al. [1].

[1] Arsigny, Commowick, Pennec, Ayache. "A log-euclidean framework for statistics on diffeomorphisms", Proc. MICCAI 2006, LNCS vol. 4190, pp. 924-931. Doi: 10.1007/11866565_113.

## Usage

### Parameters

Label | Type | Flag / Index | Default value / Channel | Description |
---|---|---|---|---|

Parameters | ||||

Delta Gradient | float | delta_grad | 0.01 | Gradient descent tolerance |

Gradient iterations | integer | Nmax_it_grad | 100 | Maximum number of iterations for gradient descent |

Rho Gradient | integer | rho_grad | 1 | Weight factor for gradient descent |

Expanding iterations | integer | N_it | 0 | Number of expanding iterations |

Sigma | float | sig_decrease | 0 | Sigma for the exponential decrease |

Smoothing radius | integer | V_radius | 3 | Smoothing radius |

Downsample/Resample | boolean | DSRS | false | DownSample / Resample VF |

IO | ||||

Input Vector Field | image(fileExtensions=".mhd" type="vector") | index 0 | input | Input Vector Field |

Output Vector Field | image (fileExtensions=".mhd" type="vector") | index 1 | output | Output Vector Field |

### Examples

Inverse applied to a vector field:

## Development

Source code: C++ Source code and XML description