--- title: "MorphologicalComponents" language: "en" type: "Symbol" summary: "MorphologicalComponents[image] gives an array in which each pixel of image is replaced by an integer index representing the connected foreground image component in which the pixel lies. MorphologicalComponents[image, t] treats values above t as foreground. MorphologicalComponents[video, ...] computes connected components in frames of video." keywords: - morphological components - find features - segmentation - feature extraction - locate features - connected components - labelling - N4 - N8 - feature detection - find clusters in image - computer vision - blob extraction - blob analysis - blob - morphological clustering - bwconncomp - bwlabel canonical_url: "https://reference.wolfram.com/language/ref/MorphologicalComponents.html" source: "Wolfram Language Documentation" related_guides: - title: "Mathematical Morphology" link: "https://reference.wolfram.com/language/guide/MathematicalMorphology.en.md" - title: "3D Images" link: "https://reference.wolfram.com/language/guide/3DImages.en.md" - title: "Segmentation Analysis" link: "https://reference.wolfram.com/language/guide/SegmentationAnalysis.en.md" - title: "Video Analysis" link: "https://reference.wolfram.com/language/guide/VideoAnalysis.en.md" - title: "Image Processing & Analysis" link: "https://reference.wolfram.com/language/guide/ImageProcessing.en.md" - title: "Video Computation: Update History" link: "https://reference.wolfram.com/language/guide/VideoComputation-UpdateHistory.en.md" - title: "Image Computation: Update History" link: "https://reference.wolfram.com/language/guide/ImageComputation-UpdateHistory.en.md" related_functions: - title: "MorphologicalPerimeter" link: "https://reference.wolfram.com/language/ref/MorphologicalPerimeter.en.md" - title: "ComponentMeasurements" link: "https://reference.wolfram.com/language/ref/ComponentMeasurements.en.md" - title: "SelectComponents" link: "https://reference.wolfram.com/language/ref/SelectComponents.en.md" - title: "WatershedComponents" link: "https://reference.wolfram.com/language/ref/WatershedComponents.en.md" - title: "ClusteringComponents" link: "https://reference.wolfram.com/language/ref/ClusteringComponents.en.md" - title: "Colorize" link: "https://reference.wolfram.com/language/ref/Colorize.en.md" - title: "HighlightImage" link: "https://reference.wolfram.com/language/ref/HighlightImage.en.md" - title: "HighlightVideo" link: "https://reference.wolfram.com/language/ref/HighlightVideo.en.md" - title: "VideoObjectTracking" link: "https://reference.wolfram.com/language/ref/VideoObjectTracking.en.md" related_tutorials: - title: "Image Processing" link: "https://reference.wolfram.com/language/tutorial/ImageProcessing.en.md" --- # MorphologicalComponents MorphologicalComponents[image] gives an array in which each pixel of image is replaced by an integer index representing the connected foreground image component in which the pixel lies. MorphologicalComponents[image, t] treats values above t as foreground. MorphologicalComponents[video, …] computes connected components in frames of video. ## Details and Options * ``MorphologicalComponents``, also known as image connected components, is a binary image segmentation technique that segments image foreground based on pixel connectivity. * ``MorphologicalComponents`` assigns sequential integers to different connected components and 0 to pixels that correspond to the background in the image. * ``MorphologicalComponents[image]`` is equivalent to ``MorphologicalComponents[image, 0]``. * ``MorphologicalComponents`` works with binary, grayscale, and other images. * The following options can be specified: | | | | | ---------------- | ----------- | ----------------------------------- | | CornerNeighbors | True | whether to include corner neighbors | | Method | "Connected" | connectivity method | | Padding | 0 | padding method to use | * The following ``Method`` settings can be specified: | | | | -------------- | ---------------------------------------------------- | | "Connected" | labels connected components | | "Nested" | labels nested connected components | | "Convex" | labels objects within non-overlapping convex regions | | "ConvexHull" | finds non-overlapping convex hulls | | "BoundingBox" | finds non-overlapping bounding boxes | | "BoundingDisk" | finds non-overlapping bounding disks | * ``MorphologicalComponents[image, Method -> "Connected"]`` also works with ``Image3D`` objects. --- ## Examples (18) ### Basic Examples (1) Find the connected components in a binary image: ```wl In[1]:= MorphologicalComponents[[image]]// Colorize Out[1]= [image] ``` ### Scope (4) Segment a binary image: ```wl In[1]:= MorphologicalComponents[[image]]//Colorize Out[1]= [image] ``` --- Segment a grayscale image, using all nonzero pixels as foreground: ```wl In[1]:= MorphologicalComponents[[image]]//Colorize Out[1]= [image] ``` Specify a background threshold: ```wl In[2]:= MorphologicalComponents[[image], .2]//Colorize Out[2]= [image] ``` --- Connected component labels: ```wl In[1]:= MorphologicalComponents[(⁠| | | | | | - | - | - | - | | 0 | 0 | 1 | 2 | | 0 | 0 | 3 | 4 | | 5 | 0 | 0 | 0 | | 6 | 7 | 0 | 0 |⁠)] // MatrixForm Out[1]//MatrixForm= (⁠| | | | | | - | - | - | - | | 0 | 0 | 1 | 1 | | 0 | 0 | 1 | 1 | | 2 | 0 | 0 | 0 | | 2 | 2 | 0 | 0 |⁠) ``` --- Connected components of a 3D image: ```wl In[1]:= MorphologicalComponents[[image]]//Colorize Out[1]= [image] ``` ### Options (10) #### CornerNeighbors (3) 8-connected objects: ```wl In[1]:= MorphologicalComponents[[image]]//MatrixForm Out[1]//MatrixForm= (⁠| | | | | | | | - | - | - | - | - | - | | 0 | 0 | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 1 | 1 | 0 | | 0 | 0 | 0 | 1 | 1 | 0 | | 0 | 1 | 1 | 0 | 0 | 0 | | 0 | 1 | 1 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | 0 | 0 |⁠) ``` --- 4-connected objects: ```wl In[1]:= MorphologicalComponents[[image], CornerNeighbors -> False] // MatrixForm Out[1]//MatrixForm= (⁠| | | | | | | | - | - | - | - | - | - | | 0 | 0 | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 1 | 1 | 0 | | 0 | 0 | 0 | 1 | 1 | 0 | | 0 | 2 | 2 | 0 | 0 | 0 | | 0 | 2 | 2 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | 0 | 0 |⁠) ``` --- Connectedness in 3D: ```wl In[1]:= i = [image]; In[2]:= Colorize@MorphologicalComponents[i, CornerNeighbors -> #]& /@ {True, False} Out[2]= {[image], [image]} ``` #### Method (6) ```wl In[1]:= MorphologicalComponents[[image]]// Colorize Out[1]= [image] ``` --- Find the bounding boxes of connected components: ```wl In[1]:= MorphologicalComponents[[image], Method -> "BoundingBox"]// Colorize Out[1]= [image] ``` --- Find the non-overlapping bounding disks: ```wl In[1]:= MorphologicalComponents[[image], Method -> "BoundingDisk"]// Colorize Out[1]= [image] ``` --- Find components whose convex hulls do not overlap: ```wl In[1]:= MorphologicalComponents[[image], Method -> "Convex"]// Colorize Out[1]= [image] ``` --- Non-overlapping convex components: ```wl In[1]:= MorphologicalComponents[[image], Method -> "ConvexHull"]// Colorize Out[1]= [image] ``` --- Label each component the same as its embedding component: ```wl In[1]:= MorphologicalComponents[[image], Method -> "Nested"]//Colorize Out[1]= [image] ``` #### Padding (1) By default, zero padding is used: ```wl In[1]:= i = [image]; In[2]:= MorphologicalComponents[i]//Colorize Out[2]= [image] ``` Using ``Padding -> 1``, all components connected to the border are assumed to be connected: ```wl In[3]:= MorphologicalComponents[i, Padding -> 1]//Colorize Out[3]= [image] ``` ### Applications (2) Count the number of bright spots, specifying an explicit thresholding value: ```wl In[1]:= MorphologicalComponents[[image], 0.8]//Max Out[1]= 3 ``` --- Count the number of pixels in each connected component of an image: ```wl In[1]:= Tally[Flatten[MorphologicalComponents[[image]]]] Out[1]= {{0, 11086}, {1, 327}, {2, 739}, {3, 348}, {4, 201}, {5, 171}, {6, 433}, {7, 1043}, {8, 502}} ``` ### Neat Examples (1) Find connected regions in a map: ```wl In[1]:= MorphologicalComponents[[image]] //Colorize Out[1]= [image] ``` ## See Also * [`MorphologicalPerimeter`](https://reference.wolfram.com/language/ref/MorphologicalPerimeter.en.md) * [`ComponentMeasurements`](https://reference.wolfram.com/language/ref/ComponentMeasurements.en.md) * [`SelectComponents`](https://reference.wolfram.com/language/ref/SelectComponents.en.md) * [`WatershedComponents`](https://reference.wolfram.com/language/ref/WatershedComponents.en.md) * [`ClusteringComponents`](https://reference.wolfram.com/language/ref/ClusteringComponents.en.md) * [`Colorize`](https://reference.wolfram.com/language/ref/Colorize.en.md) * [`HighlightImage`](https://reference.wolfram.com/language/ref/HighlightImage.en.md) * [`HighlightVideo`](https://reference.wolfram.com/language/ref/HighlightVideo.en.md) * [`VideoObjectTracking`](https://reference.wolfram.com/language/ref/VideoObjectTracking.en.md) ## Tech Notes * [Image Processing](https://reference.wolfram.com/language/tutorial/ImageProcessing.en.md) ## Related Guides * [Mathematical Morphology](https://reference.wolfram.com/language/guide/MathematicalMorphology.en.md) * [3D Images](https://reference.wolfram.com/language/guide/3DImages.en.md) * [Segmentation Analysis](https://reference.wolfram.com/language/guide/SegmentationAnalysis.en.md) * [Video Analysis](https://reference.wolfram.com/language/guide/VideoAnalysis.en.md) * [Image Processing & Analysis](https://reference.wolfram.com/language/guide/ImageProcessing.en.md) * [Video Computation: Update History](https://reference.wolfram.com/language/guide/VideoComputation-UpdateHistory.en.md) * [Image Computation: Update History](https://reference.wolfram.com/language/guide/ImageComputation-UpdateHistory.en.md) ## History * [Introduced in 2008 (7.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn70.en.md) \| [Updated in 2010 (8.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn80.en.md) ▪ [2012 (9.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn90.en.md) ▪ [2025 (14.2)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn142.en.md)