Contour extraction functions for accelerating of Simd::ContourDetector. More...

Functions
SIMD_API void	SimdContourMetrics (const uint8_t src, size_t srcStride, size_t width, size_t height, uint8_t dst, size_t dstStride)
	Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis. More...

SIMD_API void	SimdContourMetricsMasked (const uint8_t src, size_t srcStride, size_t width, size_t height, const uint8_t mask, size_t maskStride, uint8_t indexMin, uint8_t *dst, size_t dstStride)
	Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis with using mask. More...

SIMD_API void	SimdContourAnchors (const uint8_t src, size_t srcStride, size_t width, size_t height, size_t step, int16_t threshold, uint8_t dst, size_t dstStride)
	Extract contour anchors from contour metrics. More...

template<template< class > class A>
SIMD_INLINE void	ContourMetrics (const View< A > &src, View< A > &dst)
	Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis. More...

template<template< class > class A>
SIMD_INLINE void	ContourMetrics (const View< A > &src, const View< A > &mask, uint8_t indexMin, View< A > &dst)
	Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis with using mask. More...

template<template< class > class A>
SIMD_INLINE void	ContourAnchors (const View< A > &src, size_t step, int16_t threshold, View< A > &dst)
	Extract contour anchors from contour metrics. More...

Detailed Description

Contour extraction functions for accelerating of Simd::ContourDetector.

Function Documentation

◆ SimdContourMetrics()

void SimdContourMetrics	(	const uint8_t *	src,
		size_t	srcStride,
		size_t	width,
		size_t	height,
		uint8_t *	dst,
		size_t	dstStride
	)

Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis.

All images must have the same width and height. Input image must has 8-bit gray format, output image must has 16-bit integer format. This function is used for contour extraction.

For every point:

dy = abs((src[x-1,y+1] + 2*src[x, y+1] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x, y-1] + src[x+1, y-1]));
dx = abs((src[x+1,y-1] + 2*src[x+1, y] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x-1, y] + src[x-1, y+1]));
dst[x, y] = (dx + dy)*2 + (dx >= dy ? 0 : 1);

Note: This function has a C++ wrappers: Simd::ContourMetrics(const View<A>& src, View<A>& dst).

Parameters

[in]	src	- a pointer to pixels data of the gray 8-bit input image.
[in]	srcStride	- a row size of the input image.
[in]	width	- an image width.
[in]	height	- an image height.
[out]	dst	- a pointer to pixels data of the output 16-bit image.
[in]	dstStride	- a row size of the output image (in bytes).

◆ SimdContourMetricsMasked()

void SimdContourMetricsMasked	(	const uint8_t *	src,
		size_t	srcStride,
		size_t	width,
		size_t	height,
		const uint8_t *	mask,
		size_t	maskStride,
		uint8_t	indexMin,
		uint8_t *	dst,
		size_t	dstStride
	)

Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis with using mask.

All images must have the same width and height. Input image must has 8-bit gray format, output image must has 16-bit integer format. This function is used for contour extraction.

For every point:

dy = abs((src[x-1,y+1] + 2*src[x, y+1] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x, y-1] + src[x+1, y-1]));
dx = abs((src[x+1,y-1] + 2*src[x+1, y] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x-1, y] + src[x-1, y+1]));
dst[x, y] = mask[x, y] < indexMin ? 0 : (dx + dy)*2 + (dx >= dy ? 0 : 1);

Note: This function has a C++ wrappers: Simd::ContourMetrics(const View<A>& src, const View<A>& mask, uint8_t indexMin, View<A>& dst).

Parameters

[in]	src	- a pointer to pixels data of the gray 8-bit input image.
[in]	srcStride	- a row size of the input image.
[in]	width	- an image width.
[in]	height	- an image height.
[in]	mask	- a pointer to pixels data of the mask 8-bit image.
[in]	maskStride	- a row size of the mask image.
[in]	indexMin	- a mask minimal permissible index.
[out]	dst	- a pointer to pixels data of the output 16-bit image.
[in]	dstStride	- a row size of the output image (in bytes).

◆ SimdContourAnchors()

void SimdContourAnchors	(	const uint8_t *	src,
		size_t	srcStride,
		size_t	width,
		size_t	height,
		size_t	step,
		int16_t	threshold,
		uint8_t *	dst,
		size_t	dstStride
	)

Extract contour anchors from contour metrics.

All images must have the same width and height. Input image must has 16-bit integer format, output image must has 8-bit gray format. Input image with metrics can be estimated by using SimdContourMetrics or SimdContourMetricsMasked functions. This function is used for contour extraction.

For every point (except border):

a[x, y] = src[x, y] >> 1.
if(src[x, y] & 1)
    dst[x, y] = a[x, y] > 0 && (a[x, y] - a[x + 1, y] >= threshold) && (a[x, y] - a[x - 1, y] >= threshold) ? 255 : 0;
else
    dst[x, y] = a[x, y] > 0 && (a[x, y] - a[x, y + 1] >= threshold) && (a[x, y] - a[x, y - 1] >= threshold) ? 255 : 0;

Note: This function has a C++ wrappers: Simd::ContourAnchors(const View<A>& src, size_t step, int16_t threshold, View<A>& dst).

Parameters

[in]	src	- a pointer to pixels data of the 16-bit input image.
[in]	srcStride	- a row size of the input image.
[in]	width	- an image width.
[in]	height	- an image height.
[in]	step	- a row step (to skip some rows).
[in]	threshold	- a threshold of anchor creation.
[out]	dst	- a pointer to pixels data of the output 8-bit gray image.
[in]	dstStride	- a row size of the output image (in bytes).

◆ ContourMetrics() [1/2]

void ContourMetrics	(	const View< A > &	src,
		View< A > &	dst
	)

Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis.

All images must have the same width and height. Input image must has 8-bit gray format, output image must has 16-bit integer format. This function is used for contour extraction.

For every point:

dy = abs((src[x-1,y+1] + 2*src[x, y+1] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x, y-1] + src[x+1, y-1]));
dx = abs((src[x+1,y-1] + 2*src[x+1, y] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x-1, y] + src[x-1, y+1]));
dst[x, y] = (dx + dy)*2 + (dx >= dy ? 0 : 1);

Note: This function is a C++ wrapper for function SimdContourMetrics.

Parameters

[in]	src	- a gray 8-bit input image.
[out]	dst	- an output 16-bit image.

◆ ContourMetrics() [2/2]

void ContourMetrics	(	const View< A > &	src,
		const View< A > &	mask,
		uint8_t	indexMin,
		View< A > &	dst
	)

Calculates contour metrics based on absolute value and direction of Sobel's filter along y and y axis with using mask.

All images must have the same width and height. Input image must has 8-bit gray format, output image must has 16-bit integer format. This function is used for contour extraction.

For every point:

dy = abs((src[x-1,y+1] + 2*src[x, y+1] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x, y-1] + src[x+1, y-1]));
dx = abs((src[x+1,y-1] + 2*src[x+1, y] + src[x+1, y+1]) - (src[x-1,y-1] + 2*src[x-1, y] + src[x-1, y+1]));
dst[x, y] = mask[x, y] < indexMin ? 0 : (dx + dy)*2 + (dx >= dy ? 0 : 1);

Note: This function is a C++ wrapper for function SimdContourMetricsMasked.

Parameters

[in]	src	- a gray 8-bit input image.
[in]	mask	- a mask 8-bit image.
[in]	indexMin	- a mask minimal permissible index.
[out]	dst	- an output 16-bit image.

◆ ContourAnchors()

void ContourAnchors	(	const View< A > &	src,
		size_t	step,
		int16_t	threshold,
		View< A > &	dst
	)

Extract contour anchors from contour metrics.

All images must have the same width and height. Input image must has 16-bit integer format, output image must has 8-bit gray format. Input image with metrics can be estimated by using SimdContourMetrics or SimdContourMetricsMasked functions. This function is used for contour extraction.

For every point (except border):

a[x, y] = src[x, y] >> 1.
if(src[x, y] & 1)
    dst[x, y] = a[x, y] > 0 && (a[x, y] - a[x + 1, y] >= threshold) && (a[x, y] - a[x - 1, y] >= threshold) ? 255 : 0;
else
    dst[x, y] = a[x, y] > 0 && (a[x, y] - a[x, y + 1] >= threshold) && (a[x, y] - a[x, y - 1] >= threshold) ? 255 : 0;

Note: This function is a C++ wrapper for function SimdContourAnchors.

Parameters

[in]	src	- a 16-bit input image.
[in]	step	- a row step (to skip some rows).
[in]	threshold	- a threshold of anchor creation.
[out]	dst	- an output 8-bit gray image.

Simd Library Documentation.

Functions

Detailed Description

Function Documentation

◆ SimdContourMetrics()

◆ SimdContourMetricsMasked()

◆ SimdContourAnchors()

◆ ContourMetrics() [1/2]

◆ ContourMetrics() [2/2]

◆ ContourAnchors()