Documentation>C API
Data Structures
liop.h File Reference

Local Intensity Order Pattern (LIOP) descriptor (Local Intensity Order Pattern (LIOP) descriptor) More...

`#include "generic.h"`

## Data Structures

struct | VlLiopDesc
| LIOP descriptor extractor object. More...

## Functions

Construct and destroy
VlLiopDesc * | vl_liopdesc_new (vl_int numNeighbours, vl_int numSpatialBins, float radius, vl_size sideLength)
| Create a new LIOP object instance. More...
VlLiopDesc * | vl_liopdesc_new_basic (vl_size sideLength)
| Create a new object with default parameters. More...
void | vl_liopdesc_delete (VlLiopDesc *self)
| Delete object instance. More...
Get data and parameters
vl_size | vl_liopdesc_get_dimension (VlLiopDesc const *self)
| Get the dimension of a LIOP descriptor. More...
vl_size | vl_liopdesc_get_num_neighbours (VlLiopDesc const *self)
| Get the number of neighbours. More...
float | vl_liopdesc_get_intensity_threshold (VlLiopDesc const *self)
| Get the intensity threshold. More...
vl_size | vl_liopdesc_get_num_spatial_bins (VlLiopDesc const *self)
| Get the number of spatial bins. More...
double | vl_liopdesc_get_neighbourhood_radius (VlLiopDesc const *self)
| Get the neighbourhood radius. More...
void | vl_liopdesc_set_intensity_threshold (VlLiopDesc *self, float x)
| Set the intensity threshold. More...
Compute LIOP descriptor
void | vl_liopdesc_process (VlLiopDesc *liop, float *desc, float const *patch)
| Compute liop descriptor for a patch. More...

## Detailed Description

Author
  Hana Sarbortova
  Andrea Vedaldi

See also
  Local Intensity Order Pattern (LIOP) descriptor

## Function Documentation

## ◆ vl_liopdesc_delete()

void vl_liopdesc_delete | ( | VlLiopDesc * | self | ) |

Parameters

  self | object instance.

## ◆ vl_liopdesc_get_dimension()

vl_size vl_liopdesc_get_dimension | ( | VlLiopDesc const * | self | ) |

Parameters

  self | object.

Returns
  dimension.

## ◆ vl_liopdesc_get_intensity_threshold()

float vl_liopdesc_get_intensity_threshold | ( | VlLiopDesc const * | self | ) |

Parameters

  self | object.

Returns
  intensity threshold.

See also
  liop-weighing

## ◆ vl_liopdesc_get_neighbourhood_radius()

double vl_liopdesc_get_neighbourhood_radius | ( | VlLiopDesc const * | self | ) |

Parameters

  self | object.

Returns
  neighbourhood radius.

## ◆ vl_liopdesc_get_num_neighbours()

vl_size vl_liopdesc_get_num_neighbours | ( | VlLiopDesc const * | self | ) |

Parameters

  self | object.

Returns
  number of neighbours.

## ◆ vl_liopdesc_get_num_spatial_bins()

vl_size vl_liopdesc_get_num_spatial_bins | ( | VlLiopDesc const * | self | ) |

Parameters

  self | object.

Returns
  number of spatial bins.

## ◆ vl_liopdesc_new()

VlLiopDesc* vl_liopdesc_new | ( | vl_int | numNeighbours,
|  | vl_int | numSpatialBins,
|  | float | radius,
|  | vl_size | sideLength
| ) |  |

Parameters

  numNeighbours | number of neighbours.
  numSpatialBins | number of bins.
  radius | radius of the cirucal sample neighbourhoods.
  sideLength | width of the input image patch (the patch is square).

Returns
  new object instance.

The value of radius should be at least less than half the sideLength of the patch.

## ◆ vl_liopdesc_new_basic()

VlLiopDesc* vl_liopdesc_new_basic | ( | vl_size | sideLength | ) |

Parameters

  sideLength | size of the patches to be processed.

Returns
  new object.

See also
  vl_liopdesc_new.

## ◆ vl_liopdesc_process()

void vl_liopdesc_process | ( | VlLiopDesc * | self,
|  | float * | desc,
|  | float const * | patch
| ) |  |

Parameters

  self | object instance
  desc | descriptor to be computed (output).
  patch | patch to process

Use vl_liopdesc_get_dimension to get the size of the descriptor desc.

## ◆ vl_liopdesc_set_intensity_threshold()

void vl_liopdesc_set_intensity_threshold | ( | VlLiopDesc * | self,
|  | float | x
| ) |  |

Parameters

  self | object.
  x | intensity threshold.

If non-negative, the threshold as is is used when comparing intensities. If negative, the absolute value of the specified number is multipled by the maximum intensity difference inside a patch to obtain the threshold.

See also
  liop-weighing