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Morphology

Morphological operations for image processing.

Function Mapping​

libvips CDart BindingPipeline MethodPipelineSpec
vips_morph()morphologyBindings.morph()--
vips_rank()morphologyBindings.rank()pipeline.rank()spec.rank()
vips_median()morphologyBindings.median()pipeline.median()spec.median()
vips_countlines()morphologyBindings.countlines()--
vips_labelregions()morphologyBindings.labelregions()pipeline.labelregions()spec.labelregions()
vips_fill_nearest()morphologyBindings.fillNearest()pipeline.fillNearest()spec.fillNearest()

morph​

Apply morphological operation with a structuring element.

// morph(input, output, mask, morphOp)
morphologyBindings.morph(input, output, mask, VipsMorph.dilate.index);

Operations:

  • VipsMorph.erode - Erosion (shrink bright regions)
  • VipsMorph.dilate - Dilation (expand bright regions)

rank​

Apply rank filter (includes median).

// Median filter (3x3)
morphologyBindings.rank(input, output, 3, 3, 4);

// Min filter
morphologyBindings.rank(input, output, 3, 3, 0);

// Max filter
morphologyBindings.rank(input, output, 3, 3, 8);

Parameters: (input, output, width, height, index)

  • index = 0 → min
  • index = (width*height)/2 → median
  • index = width*height-1 → max

median​

Convenience function for median filter.

morphologyBindings.median(input, output, 3);  // 3x3 median

labelregions​

Label connected regions in a binary image.

// labelregions(input, maskOut)
morphologyBindings.labelregions(input, maskOut);
// Each connected region gets a unique integer label

fillNearest​

Fill holes by replacing each pixel with its nearest non-zero neighbour.

morphologyBindings.fillNearest(input, output);