Operator Reference

HALCON Operator Reference / Filters / Smoothing
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median_separatemedian_separateMedianSeparateMedianSeparatemedian_separate (Operator)

median_separatemedian_separateMedianSeparateMedianSeparatemedian_separate — 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)

def median_separate(image: HObject, mask_width: int, mask_height: int, margin: Union[int, float, str]) -> HObject

Description

The operator median_separatemedian_separateMedianSeparateMedianSeparatemedian_separate 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 MaskWidthMaskWidthMaskWidthmaskWidthmask_width followed by filtering with a vertical mask having the height MaskHeightMaskHeightMaskHeightmaskHeightmask_height 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_separateMedianSeparateMedianSeparatemedian_separate is clearly faster than the normal operator median_imagemedian_imageMedianImageMedianImagemedian_image because both masks are one pixel wide, facilitating a very efficient processing. The runtime is practically independent of the size of the mask. For example, the operator median_separatemedian_separateMedianSeparateMedianSeparatemedian_separate 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

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).
  • Multithreading scope: global (may be called from any thread).
  • Automatically parallelized on tuple level.
  • Automatically parallelized on channel level.
  • Automatically parallelized on domain level.

Parameters

ImageImageImageimageimage (input_object)  (multichannel-)image(-array) → objectHImageHObjectHObjectHobject (byte / int2 / uint2 / int4 / real)

Image to be filtered.

ImageSMedianImageSMedianImageSMedianimageSMedianimage_smedian (output_object)  (multichannel-)image(-array) → objectHImageHObjectHObjectHobject * (byte / int2 / uint2 / int4 / real)

Median filtered image.

MaskWidthMaskWidthMaskWidthmaskWidthmask_width (input_control)  extent.x → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Width of rank mask.

Default: 25

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

Value range: 1 ≤ MaskWidth MaskWidth MaskWidth maskWidth mask_width ≤ 401

Minimum increment: 2

Recommended increment: 2

MaskHeightMaskHeightMaskHeightmaskHeightmask_height (input_control)  extent.y → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Height of rank mask.

Default: 25

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

Value range: 1 ≤ MaskHeight MaskHeight MaskHeight maskHeight mask_height ≤ 401

Minimum increment: 2

Recommended increment: 2

MarginMarginMarginmarginmargin (input_control)  string → HTupleUnion[int, float, str]HTupleHtuple (string / integer / real) (string / int / long / double) (HString / Hlong / double) (char* / Hlong / double)

Border treatment.

Default: '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)

Complexity

For each pixel: O(40).

Possible Predecessors

texture_lawstexture_lawsTextureLawsTextureLawstexture_laws, sobel_ampsobel_ampSobelAmpSobelAmpsobel_amp, deviation_imagedeviation_imageDeviationImageDeviationImagedeviation_image

Possible Successors

learn_ndim_normlearn_ndim_normLearnNdimNormLearnNdimNormlearn_ndim_norm, regiongrowingregiongrowingRegiongrowingRegiongrowingregiongrowing, auto_thresholdauto_thresholdAutoThresholdAutoThresholdauto_threshold

Alternatives

median_imagemedian_imageMedianImageMedianImagemedian_image

See also

rank_imagerank_imageRankImageRankImagerank_image

References

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

Module

Foundation

ClassesClasses | | Operators