Functions
VXLIB_STATUS	VXLIB_harrisCornersScore_i16s_i16s_o32f (const int16_t src_x[restrict], const VXLIB_bufParams2D_t src_x_addr, const int16_t src_y[restrict], const VXLIB_bufParams2D_t src_y_addr, VXLIB_F32 dst[restrict], const VXLIB_bufParams2D_t *dst_addr, VXLIB_F32 scratch[restrict], VXLIB_F32 sensitivity, uint8_t gradient_size, uint8_t block_size)

VXLIB_STATUS	VXLIB_harrisCornersScore_i16s_i16s_o32f_checkParams (const int16_t src_x[restrict], const VXLIB_bufParams2D_t src_x_addr, const int16_t src_y[restrict], const VXLIB_bufParams2D_t src_y_addr, VXLIB_F32 dst[restrict], const VXLIB_bufParams2D_t *dst_addr, VXLIB_F32 scratch[restrict], VXLIB_F32 sensitivity, uint8_t gradient_size, uint8_t block_size)

Detailed Description

Function Documentation

VXLIB_STATUS VXLIB_harrisCornersScore_i16s_i16s_o32f	(	const int16_t	src_x[restrict],
		const VXLIB_bufParams2D_t *	src_x_addr,
		const int16_t	src_y[restrict],
		const VXLIB_bufParams2D_t *	src_y_addr,
		VXLIB_F32	dst[restrict],
		const VXLIB_bufParams2D_t *	dst_addr,
		VXLIB_F32	scratch[restrict],
		VXLIB_F32	sensitivity,
		uint8_t	gradient_size,
		uint8_t	block_size
	)

Description:: Given the image x and y gradients, this performs the harris score computation for a programmable neighborhood size (block_size) of each pixel.

Parameters

[in]	src_x[]	Pointer to array containing x gradient input image (SQ15.0)
[in]	src_x_addr[]	Pointer to structure containing dimensional information of src_x
[in]	src_y[]	Pointer to array containing y gradient input image (SQ15.0)
[in]	src_y_addr[]	Pointer to structure containing dimensional information of src_y
[out]	dst[]	Pointer to array containing output strengths (F32)
[in]	dst_addr[]	Pointer to structure containing dimensional information of dst
[in]	scratch[]	Pointer to scratch buffer of size = 43(block_size+1)*width bytes
[in]	sensitivity	Sensitivity threshold 'k' from the Harris-Stephens equation
[in]	gradient_size	Gradient size used to generate the sobel gradient inputs (3, 5, or 7)
[in]	block_size	Block size to use in the Harris Score computation (3, 5, or 7)

Assumptions:

I/O buffer pointers are assumed to be not aliased.
Valid output data in dst buffer is (block_size-1) pixels smaller in both horizontal and vertical directions due to neighborhood computation.
Valid gradient_size values are 3 (for 3x3 sobel), 5 (for 5x5 sobel), or 7(for 7x7 sobel)
Valid block_size values are 3 (for 3x3), 5 (for 5x5), or 7(for 7x7)
The scratch buffer should be allocated at least a buffer of size 4*3*(block_size+1)*width bytes

Performance Considerations:

For best performance, the following parameter settings are recommended:
- Set widths equal to strides
- Allocate scratch buffer in fast memory

VXLIB_STATUS VXLIB_harrisCornersScore_i16s_i16s_o32f_checkParams	(	const int16_t	src_x[restrict],
		const VXLIB_bufParams2D_t *	src_x_addr,
		const int16_t	src_y[restrict],
		const VXLIB_bufParams2D_t *	src_y_addr,
		VXLIB_F32	dst[restrict],
		const VXLIB_bufParams2D_t *	dst_addr,
		VXLIB_F32	scratch[restrict],
		VXLIB_F32	sensitivity,
		uint8_t	gradient_size,
		uint8_t	block_size
	)

Description:: Checks the parameters for programming errors for the VXLIB_harrisCornersScore_i16s_i16s_o32f function.

Method:

The following checks are made:

There shall be no NULL pointers
All inputs shall have the same x and y dimensions
Output shall have have a y dimension of at least (block_size-1) rows less than input y dimension
The strides of each image shall be equal to or greater than the x dimension

Parameters

[in]	src_x[]	Pointer to array containing x gradient input image (SQ15.0)
[in]	src_x_addr[]	Pointer to structure containing dimensional information of src_x
[in]	src_y[]	Pointer to array containing y gradient input image (SQ15.0)
[in]	src_y_addr[]	Pointer to structure containing dimensional information of src_y
[out]	dst[]	Pointer to array containing output strengths (F32)
[in]	dst_addr[]	Pointer to structure containing dimensional information of dst
[in]	scratch[]	Pointer to scratch buffer of size = 43(block_size+1)*width bytes
[in]	sensitivity	Sensitivity threshold 'k' from the Harris-Stephens equation
[in]	gradient_size	Gradient size used to generate the sobel gradient inputs (3, 5, or 7)
[in]	block_size	Block size to use in the Harris Score computation (3, 5, or 7)