VXLIB_fastCornersNMS_i8u

Functions
VXLIB_STATUS	VXLIB_fastCornersNMS_i8u (const VXLIB_bufParams2D_t *src_addr, const uint32_t corners_in[], const uint8_t strengths_in[], uint32_t num_corners_in, uint32_t corners_out[], uint8_t strengths_out[], uint32_t *num_corners_out, uint8_t scratch[], uint32_t scratch_size)
VXLIB_STATUS	VXLIB_fastCornersNMS_i8u_checkParams (const VXLIB_bufParams2D_t *src_addr, const uint32_t corners_in[], const uint8_t strengths_in[], uint32_t num_corners_in, const uint32_t corners_out[], const uint8_t strengths_out[], const uint32_t *num_corners_out, const uint8_t scratch[], uint32_t scratch_size)

Detailed Description

Function Documentation

VXLIB_fastCornersNMS_i8u()

VXLIB_STATUS VXLIB_fastCornersNMS_i8u	(	const VXLIB_bufParams2D_t *	src_addr,
		const uint32_t	corners_in[],
		const uint8_t	strengths_in[],
		uint32_t	num_corners_in,
		uint32_t	corners_out[],
		uint8_t	strengths_out[],
		uint32_t *	num_corners_out,
		uint8_t	scratch[],
		uint32_t	scratch_size
	)

Description:

Performs the FAST9 non-maximum suppression on a corner list.

Method:

Feature is kept if it's strength is >= a feature on the left, and the 3 features to the top, and it's strength is > a feature on the right, and the 3 features to the bottom.

Parameters

[in]	src_addr[]	Pointer to structure containing dimensional information of src
[in]	corners_in[]	Pointer to array containing input corner keypoint list (UQ32.0)
[in]	strengths_in[]	Pointer to array containing input strength list, coresponding to corners_in[] (UQ8.0)
[in]	num_corners_in	Total number of corners in the corners_in list.
[out]	corners_out[]	Pointer to array containing output corner keypoint list (UQ32.0)
[out]	strengths_out[]	Pointer to array containing output strength list, coresponding to corners_out[] (UQ8.0)
[out]	*num_corners_out	Total number of corners returned in the corners_out list.
[in]	scratch[]	Pointer to scratch buffer (UQ8.0)
[in]	scratch_size	Size of the scratch buffer (for parameter checking)

Assumptions:

• I/O buffer pointers are assumed to be not aliased.
• The corners_in[] array is ordered in raster-scan across and image
• 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 strengths_in[] array corresponds to the corners_in list
• The scratch buffer should be 8 byte aligned.
• The scratch buffer should be at least (4 * src_addr->dim_x) + num_corners_in + 15 bytes
• The scratch buffer should be filled with 0s prior to calling the function each time.

Performance Considerations:

• For best performance, the following parameter settings are recommended:
  • When the num_corners_in parameter is a multiple of 4.

VXLIB_fastCornersNMS_i8u_checkParams()

VXLIB_STATUS VXLIB_fastCornersNMS_i8u_checkParams	(	const VXLIB_bufParams2D_t *	src_addr,
		const uint32_t	corners_in[],
		const uint8_t	strengths_in[],
		uint32_t	num_corners_in,
		const uint32_t	corners_out[],
		const uint8_t	strengths_out[],
		const uint32_t *	num_corners_out,
		const uint8_t	scratch[],
		uint32_t	scratch_size
	)

Description:

Checks the parameters for programming errors for the VXLIB_fastCornersNMS_i8u function.

Method:

The following checks are made:

• There shall be no NULL pointers

Parameters

[in]	src_addr[]	Pointer to structure containing dimensional information of src
[in]	corners_in[]	Pointer to array containing input corner keypoint list (UQ32.0)
[in]	strengths_in[]	Pointer to array containing input strength list, coresponding to corners_in[] (UQ8.0)
[in]	num_corners_in	Total number of corners in the corners_in list.
[out]	corners_out[]	Pointer to array containing output corner keypoint list (UQ32.0)
[out]	strengths_out[]	Pointer to array containing output strength list, coresponding to corners_out[] (UQ8.0)
[out]	*num_corners_out	Total number of corners returned in the corners_out list.
[in]	scratch[]	Pointer to scratch buffer (UQ8.0)
[in]	scratch_size	Size of the scratch buffer (for parameter checking)