dsift.c File Reference

Dense SIFT (DSIFT) - Definition. More...

#include "dsift.h"
#include "pgm.h"
#include "mathop.h"
#include "imopv.h"
#include <math.h>
#include <string.h>

Go to the source code of this file.

Functions
float *	_vl_dsift_new_kernel (int binSize, int numBins, int binIndex, double windowSize)
	Initialize new convolution kernel.
float	_vl_dsift_normalize_histogram (float *begin, float *end)
	Normalize histogram.
static void	_vl_dsift_free_buffers (VlDsiftFilter *self)
	Free internal buffers.
void	_vl_dsift_update_buffers (VlDsiftFilter *self)
	Updates internal buffers to current geometry.
static void	_vl_dsift_alloc_buffers (VlDsiftFilter *self)
	Allocate internal buffers.
VlDsiftFilter *	vl_dsift_new (int imWidth, int imHeight)
	Create a new DSIFT filter.
VlDsiftFilter *	vl_dsift_new_basic (int imWidth, int imHeight, int step, int binSize)
	Create a new DSIFT filter (basic interface).
void	vl_dsift_delete (VlDsiftFilter *self)
	Delete DSIFT filter.
void	_vl_dsift_with_gaussian_window (VlDsiftFilter *self)
	Process with Gaussian window.
void	_vl_dsift_with_flat_window (VlDsiftFilter *self)
	Process with flat window.
void	vl_dsift_process (VlDsiftFilter *self, float const *im)
	Compute keypoints and descriptors.

---

Detailed Description

For internal use only.

Author:

Andrea Vedaldi

Definition in file dsift.c.

---

Function Documentation

static void _vl_dsift_alloc_buffers

(

VlDsiftFilter *

self

)

[static]

For internal use only.

Parameters:

self

DSIFT filter.

The function (re)allocates the internal buffers in accordance with the current image and descriptor geometry.

Definition at line 382 of file dsift.c.

References _vl_dsift_free_buffers(), _vl_dsift_update_buffers(), vl_dsift_get_descriptor_size(), vl_dsift_get_keypoint_num(), and vl_malloc().

Referenced by vl_dsift_process().

static void _vl_dsift_free_buffers

(

VlDsiftFilter *

self

)

[static]

For internal use only.

Parameters:

self

DSIFT filter.

Definition at line 327 of file dsift.c.

References vl_free().

Referenced by _vl_dsift_alloc_buffers(), and vl_dsift_delete().

float* _vl_dsift_new_kernel	(	int	binSize,
		int	numBins,
		int	binIndex,
		double	windowSize
	)

For internal use only.

Parameters:

	binSize
	numBins
	binIndex	negative to use flat window.
	windowSize

Returns:

a pointer to new filter.

Definition at line 258 of file dsift.c.

References vl_malloc().

Referenced by _vl_dsift_with_gaussian_window().

float _vl_dsift_normalize_histogram	(	float *	begin,
		float *	end
	)			[inline]

For internal use only.

Parameters:

	begin	first element of the histogram.
	end	last plus one element of the histogram.

The function divides the specified histogram by its l2 norm.

Definition at line 305 of file dsift.c.

References VL_EPSILON_F, and vl_fast_sqrt_f().

Referenced by vl_dsift_process().

void _vl_dsift_update_buffers

(

VlDsiftFilter *

self

)

For internal use only.

Definition at line 354 of file dsift.c.

Referenced by _vl_dsift_alloc_buffers(), vl_dsift_new(), vl_dsift_set_bounds(), vl_dsift_set_geometry(), and vl_dsift_set_steps().

void _vl_dsift_with_flat_window

(

VlDsiftFilter *

self

)

[inline]

For internal use only.

Parameters:

self

DSIFT filter object.

Definition at line 584 of file dsift.c.

References vl_dsift_get_descriptor_size(), vl_imconvcoltri_f(), VL_PAD_BY_CONTINUITY, and VL_TRANSPOSE.

Referenced by vl_dsift_process().

void _vl_dsift_with_gaussian_window

(

VlDsiftFilter *

self

)

[inline]

For internal use only.

Parameters:

self

DSIFT filter.

Definition at line 509 of file dsift.c.

References _vl_dsift_new_kernel(), vl_dsift_get_descriptor_size(), vl_free(), vl_imconvcol_vf(), VL_PAD_BY_CONTINUITY, and VL_TRANSPOSE.

Referenced by vl_dsift_process().

void vl_dsift_delete

(

VlDsiftFilter *

self

)

Parameters:

self

DSIFT filter.

Definition at line 494 of file dsift.c.

References _vl_dsift_free_buffers(), and vl_free().

VlDsiftFilter* vl_dsift_new	(	int	imWidth,
		int	imHeight
	)

Parameters:

	imWidth	width of the image.
	imHeight	height of the image

Returns:

new filter.

Definition at line 423 of file dsift.c.

References _vl_dsift_update_buffers(), VL_FALSE, and vl_malloc().

Referenced by vl_dsift_new_basic().

VlDsiftFilter* vl_dsift_new_basic	(	int	imWidth,
		int	imHeight,
		int	step,
		int	binSize
	)

Parameters:

	imWidth	width of the image.
	imHeight	height of the image.
	step	sampling step.
	binSize	bin size.

The descriptor geometry matches the standard SIFT descriptor.

Returns:

new filter.

Definition at line 477 of file dsift.c.

References VlDsiftDescriptorGeometry_::binSizeX, VlDsiftDescriptorGeometry_::binSizeY, vl_dsift_get_geometry(), vl_dsift_new(), vl_dsift_set_geometry(), and vl_dsift_set_steps().

void vl_dsift_process	(	VlDsiftFilter *	self,
		float const *	im
	)

Parameters:

	self	DSIFT filter.
	im	image data.

Definition at line 674 of file dsift.c.

References _vl_dsift_alloc_buffers(), _vl_dsift_normalize_histogram(), _vl_dsift_with_flat_window(), _vl_dsift_with_gaussian_window(), VlDsiftKeypoint_::norm, vl_dsift_get_descriptor_size(), vl_fast_atan2_f(), vl_fast_sqrt_f(), vl_floor_f(), vl_mod_2pi_f(), VL_PI, VlDsiftKeypoint_::x, and VlDsiftKeypoint_::y.