binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter (Operator)

Name

binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter — Smooth an image using the binomial filter.

Signature

binomial_filter(Image : ImageBinomial : MaskWidth, MaskHeight : )

Description

binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter smooths the image ImageImageImageImageImageimage using a binomial filter with a mask size of MaskWidthMaskWidthMaskWidthMaskWidthMaskWidthmaskWidth * MaskHeightMaskHeightMaskHeightMaskHeightMaskHeightmaskHeight pixels and returns the smoothed image in ImageBinomialImageBinomialImageBinomialImageBinomialImageBinomialimageBinomial. The binomial filter is a very good approximation of a Gaussian filter that can be implemented extremely efficiently using only integer operations. Hence, binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter is very fast. Let m = MaskHeightMaskHeightMaskHeightMaskHeightMaskHeightmaskHeight and n = MaskWidthMaskWidthMaskWidthMaskWidthMaskWidthmaskWidth. Then, the filter coefficients are given by binomial coefficients

as follows:

Here, i = 0, ..., m-1 and j = 0, ..., n-1. The binomial filter performs approximately the same smoothing as a Gaussian filter with , where for simplicity it is assumed that m = n. In detail, the relationship between n and is:

n
3	0.7523
5	1.0317
7	1.2505
9	1.4365
11	1.6010
13	1.7502
15	1.8876
17	2.0157
19	2.1361
21	2.2501
23	2.3586
25	2.4623
27	2.5618
29	2.6576
31	2.7500
33	2.8395
35	2.9262
37	3.0104

If different values are chosen for MaskHeightMaskHeightMaskHeightMaskHeightMaskHeightmaskHeight and MaskWidthMaskWidthMaskWidthMaskWidthMaskWidthmaskWidth, the above relation between n and still holds and refers to the amount of smoothing in the row and column directions.

binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter can be executed on OpenCL devices for all supported image types.

Parallelization

Supports OpenCL compute devices.
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

ImageImageImageImageImageimage (input_object) (multichannel-)image(-array) → object (byte* / uint2* / real*) *allowed for compute devices

Input image.

ImageBinomialImageBinomialImageBinomialImageBinomialImageBinomialimageBinomial (output_object) (multichannel-)image(-array) → object (byte / uint2 / real)

Smoothed image.

MaskWidthMaskWidthMaskWidthMaskWidthMaskWidthmaskWidth (input_control) integer → (integer)

Filter width.

Default value: 5

List of values: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37

MaskHeightMaskHeightMaskHeightMaskHeightMaskHeightmaskHeight (input_control) integer → (integer)

Filter height.

Default value: 5

List of values: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37

Result

If the parameter values are correct the operator binomial_filterbinomial_filterBinomialFilterbinomial_filterBinomialFilterBinomialFilter returns the value 2 (H_MSG_TRUE). The behavior in case of empty input (no input images available) is set via the operator set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary an exception is raised.

Possible Predecessors

read_imageread_imageReadImageread_imageReadImageReadImage, grab_imagegrab_imageGrabImagegrab_imageGrabImageGrabImage

Possible Successors

regiongrowingregiongrowingRegiongrowingregiongrowingRegiongrowingRegiongrowing, thresholdthresholdThresholdthresholdThresholdThreshold, sub_imagesub_imageSubImagesub_imageSubImageSubImage, dyn_thresholddyn_thresholdDynThresholddyn_thresholdDynThresholdDynThreshold, auto_thresholdauto_thresholdAutoThresholdauto_thresholdAutoThresholdAutoThreshold

Alternatives

gauss_filtergauss_filterGaussFiltergauss_filterGaussFilterGaussFilter, smooth_imagesmooth_imageSmoothImagesmooth_imageSmoothImageSmoothImage, derivate_gaussderivate_gaussDerivateGaussderivate_gaussDerivateGaussDerivateGauss, isotropic_diffusionisotropic_diffusionIsotropicDiffusionisotropic_diffusionIsotropicDiffusionIsotropicDiffusion

Module

Foundation

Operators