Morphological high-pass filter
#include "dip_morphology.h"
dip_Error dip_Tophat ( in, out, se, boundary, param, shape, edgeType, polarity )
integer, float
The top-hat is the difference between a morphological operation and the original image, comparable to a high-pass filter. Which operation is used can be chosen through the dip_MphEdgeType and dip_MphTophatPolarity parameters.
The rectangular, elliptic and diamond structuring elements are "flat", i.e. these structuring elements have a constant value. For these structuring elements, param determines the sizes of the structuring elements.
When shape is DIP_FLT_SHAPE_DISCRETE_LINE or DIP_FLT_SHAPE_INTERPOLATED_LINE, the structuring element is a line. param->array[0] determines the length, param->array[1] the angle. This is currently only supported for 2D images. Interpolated lines use interpolation to obtain a more accurate result, but loose the strict increasingness and extensivity (these properties are satisfied only by approximation).
When shape is set to DIP_FLT_SHAPE_PARABOLIC, params specifies the curvature of the parabola.
When shape is set to DIP_FLT_SHAPE_STRUCTURING_ELEMENT, se is used as structuring element. It can be either a binary or a grey-value image. Its origin is the center, or one pixel to the left of the center if the size is even.
If shape is not equal to DIP_FLT_SHAPE_STRUCTURING_ELEMENT, se can be set to zero. When shape is set to DIP_FLT_SHAPE_STRUCTURING_ELEMENT, param is ignored, and can be set to zero.
| Data type | Name | Description |
| dip_Image | in | Input |
| dip_Image | out | Output |
| dip_Image | se | Custom structuring element |
| dip_BoundaryArray | boundary | Boundary conditions |
| dip_FloatArray | param | Filter parameters |
| dip_FilterShape | shape | Structuring element |
| dip_MphEdgeType | edgeType | edgeType |
| dip_MphTophatPolarity | polarity | polarity |
The enumerator dip_FilterShape contains the following constants:
| Name | Description |
| DIP_FLT_SHAPE_DEFAULT | Default filter window, same as DIP_FLT_SHAPE_RECTANGULAR |
| DIP_FLT_SHAPE_RECTANGULAR | Rectangular filter window, can be even in size |
| DIP_FLT_SHAPE_ELLIPTIC | Elliptic filter window, always odd in size |
| DIP_FLT_SHAPE_DIAMOND | Diamond-shaped filter window, always odd in size |
| DIP_FLT_SHAPE_PARABOLIC | Parabolic filter window (morphology only) |
| DIP_FLT_SHAPE_DISCRETE_LINE | Rotated line structuring element (morphology only) |
| DIP_FLT_SHAPE_INTERPOLATED_LINE | Rotated line structuring element, through interpolation (morphology only) |
| DIP_FLT_SHAPE_PERIODIC_LINE | (not implemented) |
| DIP_FLT_SHAPE_STRUCTURING_ELEMENT | Use se as filter window, can be any size |
The enumerator dip_MphEdgeType contains the following constants:
| Name | Description |
| DIP_MPH_TEXTURE | Response is limited to edges in texture |
| DIP_MPH_OBJECT | Response is limited to object edges |
| DIP_MPH_BOTH | All edges produce equal response |
The enumerator dip_MphTophatPolarity contains the following constants:
| Name | Description |
| DIP_MPH_TEXTURE | Response is limited to edges in texture |
| DIP_MPH_OBJECT | Response is limited to object edges |
| DIP_MPH_BOTH | All edges produce equal response |
Lee, MorphologicalGradientMagnitude, MorphologicalRange, MultiScaleMorphologicalGradient, MorphologicalSmoothing, MorphologicalThreshold