dots_imagedots_imageDotsImageDotsImage (Operator)

Name

dots_imagedots_imageDotsImageDotsImage — Enhance circular dots in an image.

Signature

dots_image(Image : DotImage : Diameter, FilterType, PixelShift : )

dots_imagedots_imageDotsImageDotsImageDotsImage enhances circular dots of diameter DiameterDiameterDiameterDiameterdiameter in the input image ImageImageImageImageimage. Hence, dots_imagedots_imageDotsImageDotsImageDotsImage is especially suited for the segmentation of dot prints, e.g., in OCR applications. The enhancement is performed by using matched filters with filter masks that are tuned for a particular dot size. For example, for DiameterDiameterDiameterDiameterdiameter = 5 the filter mask is given by:

The parameter FilterTypeFilterTypeFilterTypeFilterTypefilterType selects whether 'dark'"dark""dark""dark""dark", 'light'"light""light""light""light", or 'all'"all""all""all""all" dots in the image should be enhanced. The PixelShiftPixelShiftPixelShiftPixelShiftpixelShift can be used either to increase the contrast of the output image (PixelShiftPixelShiftPixelShiftPixelShiftpixelShift > 0) or to dampen the values in extremely bright areas that would be cut off otherwise (PixelShiftPixelShiftPixelShiftPixelShiftpixelShift = -1).

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 / uint2)

Input image.

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

Output image.

DiameterDiameterDiameterDiameterdiameter (input_control) integer → (integer)

Diameter of the dots to be enhanced.

Default value: 5

List of values: 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23

FilterTypeFilterTypeFilterTypeFilterTypefilterType (input_control) string → (string)

Enhance dark, light, or all dots.

Default value: 'light' "light" "light" "light" "light"

List of values: 'all'"all""all""all""all", 'dark'"dark""dark""dark""dark", 'light'"light""light""light""light"

PixelShiftPixelShiftPixelShiftPixelShiftpixelShift (input_control) integer → (integer)

Shift of the filter response.

Default value: 0

List of values: -1, 0, 1, 2

Possible Successors

thresholdthresholdThresholdThresholdThreshold

Alternatives

laplacelaplaceLaplaceLaplaceLaplace, laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss, diff_of_gaussdiff_of_gaussDiffOfGaussDiffOfGaussDiffOfGauss, derivate_gaussderivate_gaussDerivateGaussDerivateGaussDerivateGauss, convol_imageconvol_imageConvolImageConvolImageConvolImage

Module

Foundation

Operators