Class

MPSImageDilate

A filter that finds the maximum pixel value in a rectangular region centered around each pixel in the source image.

Declaration

class MPSImageDilate : MPSUnaryImageKernel

Overview

An MPSImageDilate filter behaves like the MPSImageAreaMax filter, except that the intensity at each position is calculated relative to a different value before determining which is the maximum pixel value, allowing for shaped, non-rectangular morphological probes.

Listing 1 shows pseudocode for the calculation used to return each pixel value.

Listing 1

MPSImageDilate Pseudocode

for each pixel in the filter window
    value = pixel[filterY][filterX] - filter[filterY*filter_width+filterX]
    if( value > bestValue ){
        result = value
        bestValue = value
    }

A filter that contains all zeros is identical to an MPSImageAreaMax filter. The center filter element is assumed to be 0 to avoid causing a general darkening of the image. The edgeMode property value is assumed to always be MPSImageEdgeMode.clamp for this filter.