VXLIB_fastCornersScore_i8u

Functions
VXLIB_STATUS	VXLIB_fastCornersScore_i8u (const uint8_t src[], const VXLIB_bufParams2D_t *src_addr, const uint32_t corners[], uint8_t strengths[], uint8_t strength_thresh, uint32_t num_corners, uint8_t scratch[], uint32_t scratch_size)
VXLIB_STATUS	VXLIB_fastCornersScore_i8u_checkParams (const uint8_t src[], const VXLIB_bufParams2D_t *src_addr, const uint32_t corners[], const uint8_t strengths[], uint8_t strength_thresh, uint32_t num_corners, const uint8_t scratch[], uint32_t scratch_size)

Detailed Description

Function Documentation

VXLIB_fastCornersScore_i8u()

VXLIB_STATUS VXLIB_fastCornersScore_i8u	(	const uint8_t	src[],
		const VXLIB_bufParams2D_t *	src_addr,
		const uint32_t	corners[],
		uint8_t	strengths[],
		uint8_t	strength_thresh,
		uint32_t	num_corners,
		uint8_t	scratch[],
		uint32_t	scratch_size
	)

Description:

Computes the FAST9 strenghts for each corner in the corner list.

Method:

FAST9 algorithm.

Parameters

[in]	src[]	Pointer to array containing input image (UQ8.0)
[in]	src_addr[]	Pointer to structure containing dimensional information of src
[in]	corners[]	Pointer to array containing corner keypoint list (UQ32.0)
[out]	strengths[]	Pointer to array containing strength list corresponding to corners[] (UQ8.0)
[in]	strength_thresh	Threshold on difference between intensity of the central pixel and pixels on the Bresenham's circlue of radius 3.
[in]	num_corners	Total number of corners in the corners list.
[in]	scratch[]	Pointer to scratch buffer of at least 463 bytes (UQ8.0)
[in]	scratch_size	Size of scratch buffer in number of bytes (for parameter checking)

Assumptions:

• I/O buffer pointers are assumed to be not aliased.
• 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);
• The scratch buffer should be at least 463 bytes

Performance Considerations:

• For best performance, the following parameter settings are recommended:
  • When the num_corners parameter is a multiple of 8.

VXLIB_fastCornersScore_i8u_checkParams()

VXLIB_STATUS VXLIB_fastCornersScore_i8u_checkParams	(	const uint8_t	src[],
		const VXLIB_bufParams2D_t *	src_addr,
		const uint32_t	corners[],
		const uint8_t	strengths[],
		uint8_t	strength_thresh,
		uint32_t	num_corners,
		const uint8_t	scratch[],
		uint32_t	scratch_size
	)

Description:

Checks the parameters for programming errors for the VXLIB_fastCornersScore_i8u function.

Method:

The following checks are made:

• There shall be no NULL pointers
• The strides of the image shall be equal to or greater than the x dimension
• The scratch_size shall be >= 463

Parameters

[in]	src[]	Pointer to array containing input image (UQ8.0)
[in]	src_addr[]	Pointer to structure containing dimensional information of src
[in]	corners[]	Pointer to array containing corner keypoint list (UQ32.0)
[out]	strengths[]	Pointer to array containing strength list corresponding to corners[] (UQ8.0)
[in]	strength_thresh	Threshold on difference between intensity of the central pixel and pixels on the Bresenham's circlue of radius 3.
[in]	num_corners	Total number of corners in the corners list.
[in]	scratch[]	Pointer to scratch buffer (UQ8.0)
[in]	scratch_size	Size of scratch buffer in number of bytes (for parameter checking)