Functions
I32	median3 (image src, image dst)
	3×3 Median Filter. More...

I32	pmed5x5 (image src, image dst)
	5×5 Pseudo Median Filter with Horizontal/Vertical Separation. More...

I32	pmed7x7 (image src, image dst)
	7×7 Pseudo Median Filter with Horizontal/Vertical Separation. More...

I32	median1xN (image src, image dst, I32 my)
	1×N Median Filter. More...

I32	medianNx1 (image src, image dst, I32 mx)
	N×1 Median Filter. More...

I32	vc_median_anisotropic_1x9 (image vec, image out)
	Anisotropic 1×9 Median Filter at a Vector Image. More...

I32	vc_median_anisotropic_1x9_padded (image vec, image out)
	Anisotropic 1×9 Median Filter at a Vector Image, padded with 0. More...

I32	maxMxN (image src, image dst, I32 mx, I32 my)
	Moving Maximum (Dilation) Filter. More...

I32	minMxN (image src, image dst, I32 mx, I32 my)
	Moving Minimum (Erosion) Filter. More...

Detailed Description

Function Documentation

◆ maxMxN()

I32 maxMxN	(	image *	src,
		image *	dst,
		I32	mx,
		I32	my
	)

The function calculates the moving maximum filter (grey value dilation) with a filter kernel of size (mx, my). It is possible to set either mx or my to one, in which case a linear horizontal or vertical structuring element is used. It is not possible to use this function in-place, i.e src and dst must be different. The execution time is independent of the mask size. The function returns the standard error code.

Parameters

src	Source Image.
dst	Destination Image.
mx,my	Filter Size.

Memory Consumption: dx Bytes of Heap Memory.

See also: minMxN().

Return values

ERR_TYPE	if `src` or `dst` Image is no Grey Image.
ERR_PARAM	if `mx` not in [1,dx] or `my` not in [1,dy].
ERR_PARAM	if `src`->`st` = `dst`->`st`.
ERR_MEMORY	if Memory Allocation Fails.
ERR_NONE	on Success.
ERR_TYPE	if `src` or `dst` Image is no Grey Image.
ERR_PARAM	if `mx` not in [1,dx] or `my` not in [1,dy].
ERR_PARAM	if `src`->`st` = `dst`->`st`.
ERR_MEMORY	if Memory Allocation Fails.
ERR_NONE	on Success.

◆ minMxN()

I32 minMxN	(	image *	src,
		image *	dst,
		I32	mx,
		I32	my
	)

The function calculates the moving minimum filter (grey value erosion) with a filter kernel of size (mx, my). It is possible to set either mx or my to one, in which case a linear horizontal or vertical structuring element is used. It is not possible to use this function in-place, i.e src and dst must be different. The exection time is independent of the mask size. The function returns the standard error code.

Parameters

src	Source Image.
dst	Destination Image.
mx,my	Filter Size.

Memory Consumption: dx Bytes of Heap Memory.

See also: maxMxN().

Return values

ERR_TYPE	if `src` or `dst` Image is no Grey Image.
ERR_PARAM	if `mx` not in [1,dx] or `my` not in [1,dy].
ERR_PARAM	if `src`->`st` = `dst`->`st`.
ERR_MEMORY	if Memory Allocation Fails.
ERR_NONE	on Success.
ERR_TYPE	if `src` or `dst` Image is no Grey Image.
ERR_PARAM	if `mx` not in [1,dx] or `my` not in [1,dy].
ERR_PARAM	if `src`->`st` = `dst`->`st`.
ERR_MEMORY	if Memory Allocation Fails.
ERR_NONE	on Success.

◆ median3()

I32 median3	(	image *	src,
		image *	dst
	)

Parameters

a	Source Image.
b	Destination Image, May be Identical.

See also: median1xN(), medianNx1().

The median3() now fills the complete output image b instead of a previous version.

Note that the output pixel position is equal to the top left pixel position of the 3×3 matrix. The advantage of that positioning is the ability to use the input image as the output image. Also note that the last two columns and the last two rows of the image contain meaningless data. A simple approach to register the output pixel position to the center position and interpolation at the border comes with the following code, but at a cost of memory and processing time:

I32  median3_centered(image *a)
{
    image  sImgEdge = NULL_IMAGE;
    if(ERR_NONE !=  ImageAllocateEdge(a, &sImgEdge, 1, 1))
    { return ERR_MEMORY; }
    median3(&sImgEdge, a);
    
    ImageFree(&sImgEdge);
}

Return values

ERR_TYPE if src or dst image is no grey compatible image.

◆ pmed5x5()

I32 pmed5x5	(	image *	src,
		image *	dst
	)

The function performs a 5×5 median filter for an image variable src. The filter consists of a 1×5 and a 5×1 median which are executed in sequence. The result of the operation will be stored in image dst.

See also: pmed7x7().

Return values

ERR_TYPE	if `src` or `dst` Image is no Grey Image.
ERR_NONE	on Success.

◆ pmed7x7()

I32 pmed7x7	(	image *	src,
		image *	dst
	)

The function performs a 7×7 median filter for an image variable src. The filter consists of a 1×7 and a 7×1 median which are executed in sequence. The result of the operation will be stored in image dst.

See also: pmed5x5().

Return values

ERR_TYPE	if `src` or `dst` image is not grey compatible.
ERR_NONE	on Success.

◆ median1xN()

I32 median1xN	(	image *	src,
		image *	dst,
		I32	my
	)

Parameters

src	Source Image
dst	Destination Image, May be identical.
my	Filter Size

◆ medianNx1()

I32 medianNx1	(	image *	src,
		image *	dst,
		I32	mx
	)

Parameters

src	Source Image
dst	Destination Image, May be identical.
mx	Filter Size

◆ vc_median_anisotropic_1x9()

I32 vc_median_anisotropic_1x9	(	image *	vec,
		image *	out
	)

The function makes it possible to calculate an anisotropic 1×9 median filter operation at a vector image. Therefore the direction at the center pixel of a 9×9 frame will define the angle of the 1×9 pixel line through that point which selects the points whose magnitudes will be medianized for that pixel, and the direction of the winning median pixel is copied to the output.

Note that the output pixel position is equal to the top left pixel position of the 9×9 matrix. The advantage of that positioning is the ability to use the input image as the output image. Also note that the last nine columns and the last nine rows of the image contain meaningless data.

Parameters

vec	Source image of type IMAGE_VECTOR.
out	Destination image of type IMAGE_VECTOR.

Returns: ERR_TYPE if any of the images is not of type IMAGE_VECTOR.

Memory Consumption: None.

◆ vc_median_anisotropic_1x9_padded()

I32 vc_median_anisotropic_1x9_padded	(	image *	vec,
		image *	out
	)

The function makes it possible to calculate an anisotropic 1×9 median filter operation at a vector image, see vc_median_anisotropic_1x9() for more information.

The input image is padded by a 4-pixel-border filled with 0 at the st channel, with 0x80 at the ccmp1 channel compatible to the gradient_3x3_thresh() meaning of direction. This is only relevant if the vector input is 0 at its border frame, so there may be dir 0x80s used for magnitude 0(!) at the border.

The result is as big as the input image.

Parameters

vec	Source image of type IMAGE_VECTOR.
out	Destination image of type IMAGE_VECTOR.

Returns: 0 on success.

Rank Filter

Functions

Detailed Description

Function Documentation

◆ maxMxN()

◆ minMxN()

◆ median3()

◆ pmed5x5()

◆ pmed7x7()

◆ median1xN()

◆ medianNx1()

◆ vc_median_anisotropic_1x9()

◆ vc_median_anisotropic_1x9_padded()