median_separatemedian_separateMedianSeparateMedianSeparate (Operator)

Name

median_separatemedian_separateMedianSeparateMedianSeparate — Separated median filtering with rectangle masks.

Signature

median_separate(Image : ImageSMedian : MaskWidth, MaskHeight, Margin : )

Herror median_separate(const Hobject Image, Hobject* ImageSMedian, const Hlong MaskWidth, const Hlong MaskHeight, const char* Margin)

Herror T_median_separate(const Hobject Image, Hobject* ImageSMedian, const Htuple MaskWidth, const Htuple MaskHeight, const Htuple Margin)

void MedianSeparate(const HObject& Image, HObject* ImageSMedian, const HTuple& MaskWidth, const HTuple& MaskHeight, const HTuple& Margin)

HImage HImage::MedianSeparate(Hlong MaskWidth, Hlong MaskHeight, const HTuple& Margin) const

HImage HImage::MedianSeparate(Hlong MaskWidth, Hlong MaskHeight, const HString& Margin) const

HImage HImage::MedianSeparate(Hlong MaskWidth, Hlong MaskHeight, const char* Margin) const

HImage HImage::MedianSeparate(Hlong MaskWidth, Hlong MaskHeight, const wchar_t* Margin) const   (Windows only)

static void HOperatorSet.MedianSeparate(HObject image, out HObject imageSMedian, HTuple maskWidth, HTuple maskHeight, HTuple margin)

HImage HImage.MedianSeparate(int maskWidth, int maskHeight, HTuple margin)

HImage HImage.MedianSeparate(int maskWidth, int maskHeight, string margin)

Description

The operator median_separatemedian_separateMedianSeparateMedianSeparateMedianSeparate carries out a variation of the median filtering: First two auxiliary images are created. The first one originates from a median filtering with a horizontal mask having a height of one pixel and the width MaskWidthMaskWidthMaskWidthMaskWidthmaskWidth followed by filtering with a vertical mask having the height MaskHeightMaskHeightMaskHeightMaskHeightmaskHeight and width of one pixel. The second auxiliary image is created by filtering with the same masks, but with a reversed sequence of the operation: first the vertical, then the horizontal mask. The output image results from averaging the two auxiliary images pixel by pixel.

The operator median_separatemedian_separateMedianSeparateMedianSeparateMedianSeparate is clearly faster than the normal operator median_imagemedian_imageMedianImageMedianImageMedianImage because both masks are one pixel wide, facilitating a very effecient processing. The runtime is practically independent of the size of the mask. For example, the operator median_separatemedian_separateMedianSeparateMedianSeparateMedianSeparate can be well used after texture filters, where large masks are needed.

The filter can also be used several times in a row in order to enhance the smoothing.

For an explanation of the concept of smoothing filters see the introduction of chapter Filters / Smoothing.

Attention

Note that filter operators may return unexpected results if an image with a reduced domain is used as input. Please refer to the chapter Filters.

Due to performance reasons, the input ImageImageImageImageimage is not checked whether it contains NaNs. Using an input image with NaNs crashes HALCON.

Execution Information

Parameters

ImageImageImageImageimage (input_object)  (multichannel-)image(-array) objectHImageHImageHobject (byte / int2 / uint2 / int4 / real)

Image to be filtered.

ImageSMedianImageSMedianImageSMedianImageSMedianimageSMedian (output_object)  (multichannel-)image(-array) objectHImageHImageHobject * (byte / int2 / uint2 / int4 / real)

Median filtered image.

MaskWidthMaskWidthMaskWidthMaskWidthmaskWidth (input_control)  extent.x HTupleHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Width of rank mask.

Default value: 25

Suggested values: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 27, 43, 51, 67, 91, 121, 151

Typical range of values: 1 ≤ MaskWidth MaskWidth MaskWidth MaskWidth maskWidth ≤ 401

Minimum increment: 2

Recommended increment: 2

MaskHeightMaskHeightMaskHeightMaskHeightmaskHeight (input_control)  extent.y HTupleHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Height of rank mask.

Default value: 25

Suggested values: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 27, 43, 51, 67, 91, 121, 151

Typical range of values: 1 ≤ MaskHeight MaskHeight MaskHeight MaskHeight maskHeight ≤ 401

Minimum increment: 2

Recommended increment: 2

MarginMarginMarginMarginmargin (input_control)  string HTupleHTupleHtuple (string / integer / real) (string / int / long / double) (HString / Hlong / double) (char* / Hlong / double)

Border treatment.

Default value: 'mirrored' "mirrored" "mirrored" "mirrored" "mirrored"

Suggested values: 'mirrored'"mirrored""mirrored""mirrored""mirrored", 'cyclic'"cyclic""cyclic""cyclic""cyclic", 'continued'"continued""continued""continued""continued", 0, 30, 60, 90, 120, 150, 180, 210, 240, 255

Example (HDevelop)

read_image(Image,'fabrik')
median_separate(Image,MedianSeparate,5,5,3)
dev_display(MedianSeparate)

Example (C)

read_image(&Image,"fabrik");
median_separate(Image,&MedianSeparate,5,5,3);
disp_image(MedianSeparate,WindowHandle);

Example (HDevelop)

read_image(Image,'fabrik')
median_separate(Image,MedianSeparate,5,5,3)
dev_display(MedianSeparate)

Example (HDevelop)

read_image(Image,'fabrik')
median_separate(Image,MedianSeparate,5,5,3)
dev_display(MedianSeparate)

Example (HDevelop)

read_image(Image,'fabrik')
median_separate(Image,MedianSeparate,5,5,3)
dev_display(MedianSeparate)

Complexity

For each pixel: O(40).

Possible Predecessors

texture_lawstexture_lawsTextureLawsTextureLawsTextureLaws, sobel_ampsobel_ampSobelAmpSobelAmpSobelAmp, deviation_imagedeviation_imageDeviationImageDeviationImageDeviationImage

Possible Successors

learn_ndim_normlearn_ndim_normLearnNdimNormLearnNdimNormLearnNdimNorm, regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowing, auto_thresholdauto_thresholdAutoThresholdAutoThresholdAutoThreshold

Alternatives

median_imagemedian_imageMedianImageMedianImageMedianImage

See also

rank_imagerank_imageRankImageRankImageRankImage

References

R. Haralick, L. Shapiro; “Computer and Robot Vision”; Addison-Wesley, 1992, Seite 319

Module

Foundation