VXLIB_harrisCornersDetect_i32f

Functions
VXLIB_STATUS	VXLIB_harrisCornersDetect_i32f (const VXLIB_F32 src[restrict], const VXLIB_bufParams2D_t *src_addr, uint32_t corners[restrict], VXLIB_F32 strengths[restrict], uint32_t corners_capacity, uint32_t *num_corners, VXLIB_F32 strength_thresh, uint16_t startX, uint16_t startY)
VXLIB_STATUS	VXLIB_harrisCornersDetect_i32f_checkParams (const VXLIB_F32 src[], const VXLIB_bufParams2D_t *src_addr, const uint32_t corners[], const VXLIB_F32 strengths[], uint32_t corners_capacity, const uint32_t *num_corners, VXLIB_F32 strength_thresh, uint16_t startX, uint16_t startY)

Detailed Description

Function Documentation

VXLIB_harrisCornersDetect_i32f()

VXLIB_STATUS VXLIB_harrisCornersDetect_i32f	(	const VXLIB_F32	src[restrict],
		const VXLIB_bufParams2D_t *	src_addr,
		uint32_t	corners[restrict],
		VXLIB_F32	strengths[restrict],
		uint32_t	corners_capacity,
		uint32_t *	num_corners,
		VXLIB_F32	strength_thresh,
		uint16_t	startX,
		uint16_t	startY
	)

Description:

Given the harris score for each pixel, this function performs a threshold and non-maximum suppression operation on the immediate neighborhood pixels. The outputs of the operation are 2 arrays: 1 array for the coordinates of the possible corners, and its associated list of strength values for further processing.

Method:

Parameters

[in]	src[]	Pointer to array containing harris strength values (F32)
[in]	src_addr[]	Pointer to structure containing dimensional information of src
[out]	corners[]	Pointer to array containing corner keypoint list (UQ32.0)
[out]	strengths[]	Pointer to array containing corner strength list corresponding to corners[] list (F32)
[in]	corners_capacity	Number of keypoints allocated in the corners and strengths buffers.
[out]	num_corners	Total number of corners found in the image.
[in]	strength_thresh	Threshold on minimum strength value for a corner to be considered.
[in]	startX	Starting x coordinate corresponding to the pixel at the src[] pointer
[in]	startY	Starting y coordinate corresponding to the pixel at the src[] pointer

Assumptions:

• I/O buffer pointers are assumed to be not aliased.
• The minimum image width and height are both 3.
• Corners can not be detected in the 1 pixel that makes up the image border.
• Each 32-bit word in corners[] array is composed of 2 16-bit half words representing x and y coordinates, such that corners[i] = (y(i) << 16) | x(i);

Performance Considerations:

• For best performance, the following parameter settings are recommended:
  • Width as a multiple of 2

VXLIB_harrisCornersDetect_i32f_checkParams()

VXLIB_STATUS VXLIB_harrisCornersDetect_i32f_checkParams	(	const VXLIB_F32	src[],
		const VXLIB_bufParams2D_t *	src_addr,
		const uint32_t	corners[],
		const VXLIB_F32	strengths[],
		uint32_t	corners_capacity,
		const uint32_t *	num_corners,
		VXLIB_F32	strength_thresh,
		uint16_t	startX,
		uint16_t	startY
	)

Description:

Checks the parameters for programming errors for the VXLIB_harrisCornersDetect_i32f function.

Method:

The following checks are made:

• There shall be no NULL pointers
• The strides of each image shall be equal to or greater than the x dimension

Parameters

[in]	src[]	Pointer to array containing harris strength values (F32)
[in]	src_addr[]	Pointer to structure containing dimensional information of src
[out]	corners[]	Pointer to array containing corner keypoint list (UQ32.0)
[out]	strengths[]	Pointer to array containing corner strength list corresponding to corners[] list (F32)
[in]	corners_capacity	Number of keypoints allocated in the corners and strengths buffers.
[out]	num_corners	Total number of corners found in the image.
[in]	strength_thresh	Threshold on minimum strength value for a corner to be considered.
[in]	startX	Starting x coordinate corresponding to the pixel at the src[] pointer
[in]	startY	Starting y coordinate corresponding to the pixel at the src[] pointer