include/colmap/lib/VLFeat/quickshift.h

/** @file quickshift.h
 ** @brief Quick shift (@ref quickshift)
 ** @author Andrea Vedaldi
 ** @author Brian Fulkerson
 **/

/*
Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
All rights reserved.

This file is part of the VLFeat library and is made available under
the terms of the BSD license (see the COPYING file).
*/

#ifndef VL_QUICKSHIFT_H
#define VL_QUICKSHIFT_H

#include "generic.h"
#include "mathop.h"

/** @brief quick shift datatype */
typedef double vl_qs_type ;

/** @brief quick shift infinity constant */
#define VL_QS_INF VL_INFINITY_D /* Change to _F for float math */

/** ------------------------------------------------------------------
 ** @brief quick shift results
 **
 ** This implements quick shift mode seeking.
 **/

typedef struct _VlQS
{
  vl_qs_type *image ;   /**< height x width x channels feature image */
  int height;           /**< height of the image */
  int width;            /**< width of the image */
  int channels;         /**< number of channels in the image */

  vl_bool medoid;
  vl_qs_type sigma;
  vl_qs_type tau;

  int *parents ;
  vl_qs_type *dists ;
  vl_qs_type *density ;
} VlQS ;

/** @name Create and destroy
 ** @{
 **/
VL_EXPORT
VlQS*  vl_quickshift_new (vl_qs_type const * im, int height, int width,
                          int channels);

VL_EXPORT
void   vl_quickshift_delete (VlQS *q) ;
/** @} */

/** @name Process data
 ** @{
 **/

VL_EXPORT
void   vl_quickshift_process (VlQS *q) ;

/** @} */

/** @name Retrieve data and parameters
 ** @{
 **/
VL_INLINE vl_qs_type    vl_quickshift_get_max_dist      (VlQS const *q) ;
VL_INLINE vl_qs_type    vl_quickshift_get_kernel_size    (VlQS const *q) ;
VL_INLINE vl_bool       vl_quickshift_get_medoid   (VlQS const *q) ;

VL_INLINE int *        vl_quickshift_get_parents  (VlQS const *q) ;
VL_INLINE vl_qs_type * vl_quickshift_get_dists    (VlQS const *q) ;
VL_INLINE vl_qs_type * vl_quickshift_get_density  (VlQS const *q) ;
/** @} */

/** @name Set parameters
 ** @{
 **/
VL_INLINE void vl_quickshift_set_max_dist    (VlQS *f, vl_qs_type tau) ;
VL_INLINE void vl_quickshift_set_kernel_size  (VlQS *f, vl_qs_type sigma) ;
VL_INLINE void vl_quickshift_set_medoid (VlQS *f, vl_bool medoid) ;
/** @} */

/* -------------------------------------------------------------------
 *                                     Inline functions implementation
 * ---------------------------------------------------------------- */

/** ------------------------------------------------------------------
 ** @brief Get tau.
 ** @param q quick shift object.
 ** @return the maximum distance in the feature space between nodes in the
 **         quick shift tree.
 **/

VL_INLINE vl_qs_type
vl_quickshift_get_max_dist (VlQS const *q)
{
  return q->tau ;
}

/** ------------------------------------------------------------------
 ** @brief Get sigma.
 ** @param q quick shift object.
 ** @return the standard deviation of the kernel used in the Parzen density
 **         estimate.
 **/

VL_INLINE vl_qs_type
vl_quickshift_get_kernel_size (VlQS const *q)
{
  return q->sigma ;
}

/** ------------------------------------------------------------------
 ** @brief Get medoid.
 ** @param q quick Shift object.
 ** @return @c true if medoid shift is used instead of quick shift.
 **/

VL_INLINE vl_bool
vl_quickshift_get_medoid (VlQS const *q)
{
  return q->medoid ;
}

/** ------------------------------------------------------------------
 ** @brief Get parents.
 ** @param q quick shift object.
 ** @return a @c height x @c width matrix where each element contains the
 **         linear index of its parent node. The node is a root if its
 **         value is its own linear index.
 **/

VL_INLINE int *
vl_quickshift_get_parents (VlQS const *q)
{
  return q->parents ;
}

/** ------------------------------------------------------------------
 ** @brief Get dists.
 ** @param q quick shift object.
 ** @return for each pixel, the distance in feature space to the pixel
 **         that is its parent in the quick shift tree. The distance is
 **         set to 'inf' if the pixel is a root node.
 **/

VL_INLINE vl_qs_type *
vl_quickshift_get_dists (VlQS const *q)
{
  return q->dists ;
}

/** ------------------------------------------------------------------
 ** @brief Get density.
 ** @param q quick shift object.
 ** @return the estimate of the density at each pixel.
 **/

VL_INLINE vl_qs_type *
vl_quickshift_get_density (VlQS const *q)
{
  return q->density ;
}

/** ------------------------------------------------------------------
 ** @brief Set sigma
 ** @param q quick shift object.
 ** @param sigma standard deviation of the kernel used in the Parzen density
 **        estimate.
 **/

VL_INLINE void
vl_quickshift_set_kernel_size (VlQS *q, vl_qs_type sigma)
{
  q -> sigma = sigma ;
}

/** ------------------------------------------------------------------
 ** @brief Set max distance
 ** @param q quick shift object.
 ** @param tau the maximum distance in the feature space between nodes in the
 **            quick shift tree.
 **/

VL_INLINE void
vl_quickshift_set_max_dist (VlQS *q, vl_qs_type tau)
{
  q -> tau = tau ;
}

/** ------------------------------------------------------------------
 ** @brief Set medoid
 ** @param q quick shift object.
 ** @param medoid @c true to use kernelized medoid shift, @c false (default) uses
 **        quick shift.
 **/

VL_INLINE void
vl_quickshift_set_medoid (VlQS *q, vl_bool medoid)
{
  q -> medoid = medoid ;
}


#endif