Operator Reference

median_weightedmedian_weightedMedianWeightedMedianWeightedmedian_weighted (Operator)

median_weightedmedian_weightedMedianWeightedMedianWeightedmedian_weighted — Weighted median filtering with different rank masks.

Signature

median_weighted(Image : ImageWMedian : MaskType, MaskSize : )

Description

The operator median_weightedmedian_weightedMedianWeightedMedianWeightedmedian_weighted calculates the median of the gray values within a local environment. In contrast to median_imagemedian_imageMedianImageMedianImagemedian_image, which uses all gray values within the environment exactly once, the operator median_weightedmedian_weightedMedianWeightedMedianWeightedmedian_weighted weights all gray values several times depending on their position. A gray value is received into the field to be sorted several times according to its weighting. The following masks are available:

'gauss': (MaskSizeMaskSizeMaskSizemaskSizemask_size = 3) 1 2 1 2 4 2 1 2 1
'inner': (MaskSizeMaskSizeMaskSizemaskSizemask_size = 3) 1 1 1 1 3 1 1 1 1

The operator median_weightedmedian_weightedMedianWeightedMedianWeightedmedian_weighted means that, contrary to median_imagemedian_imageMedianImageMedianImagemedian_image, gray value corners remain.

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.

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) → object (byte / int2 / uint2)

Image to be filtered.

ImageWMedianImageWMedianImageWMedianimageWMedianimage_wmedian (output_object) (multichannel-)image(-array) → object (byte / int2 / uint2)

Median filtered image.

MaskTypeMaskTypeMaskTypemaskTypemask_type (input_control) string → (string)

Type of median mask.

Default: 'inner' "inner" "inner" "inner" "inner"

List of values: 'gauss'"gauss""gauss""gauss""gauss", 'inner'"inner""inner""inner""inner"

MaskSizeMaskSizeMaskSizemaskSizemask_size (input_control) integer → (integer)

mask size.

Default: 3

List of values: 3

Example (HDevelop)

read_image(Image,'fabrik')
median_weighted(Image,MedianWeighted,'gauss',3)
dev_display(MedianWeighted)

Example (C)

read_image(&Image,"fabrik");
median_weighted(Image,&MedianWeighted,"gauss",3);
disp_image(MedianWeighted,WindowHandle);

Example (HDevelop)

read_image(Image,'fabrik')
median_weighted(Image,MedianWeighted,'gauss',3)
dev_display(MedianWeighted)

Example (HDevelop)

read_image(Image,'fabrik')
median_weighted(Image,MedianWeighted,'gauss',3)
dev_display(MedianWeighted)

Complexity

For each pixel: O(F * log(F)) with F = area of MaskTypeMaskTypeMaskTypemaskTypemask_type.

Possible Predecessors

read_imageread_imageReadImageReadImageread_image

Possible Successors

thresholdthresholdThresholdThresholdthreshold, dyn_thresholddyn_thresholdDynThresholdDynThresholddyn_threshold, regiongrowingregiongrowingRegiongrowingRegiongrowingregiongrowing

Alternatives

median_imagemedian_imageMedianImageMedianImagemedian_image, trimmed_meantrimmed_meanTrimmedMeanTrimmedMeantrimmed_mean, sigma_imagesigma_imageSigmaImageSigmaImagesigma_image

References

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

Module

Foundation

Operators