imclose

Morphologically close image

Syntax

J = imclose(I,SE)

J = imclose(I,nhood)

Description

J = imclose(I,SE) performs morphological closing on the grayscale or binary image I, returning the closed image, J. SE is a single structuring element object returned by the strel or offsetstrel functions. The morphological close operation is a dilation followed by an erosion, using the same structuring element for both operations.

J = imclose(I,nhood) closes the image I, where nhood is a matrix of 0s and 1s that specifies the structuring element neighborhood. The imclose function determines the center element of the neighborhood by floor((size(nhood)+1)/2).

This syntax is equivalent to imclose(I,strel(nhood)).

Examples

Use Morphological Closing to Fill Gaps in an Image

Read a binary image into the workspace and display it.

originalBW = imread('circles.png');
imshow(originalBW);

Create a disk-shaped structuring element. Use a disk structuring element to preserve the circular nature of the object. Specify a radius of 10 pixels so that the largest gap gets filled.

se = strel('disk',10);

Perform a morphological close operation on the image.

closeBW = imclose(originalBW,se);
figure, imshow(closeBW)

Input Arguments

I — Input image

grayscale image | binary image

Input image, specified as a grayscale image or binary image of any dimension.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | logical

SE — Structuring element

strel object | offsetstrel object

Structuring element, specified as a single strel object or offsetstrel object. If the image I is data type logical, then the structuring element must be flat.

nhood — Structuring element neighborhood

matrix of 0s and 1s

Structuring element neighborhood, specified as a matrix of 0s and 1s.

Example: [0 1 0; 1 1 1; 0 1 0]

Output Arguments

J — Closed image

grayscale image | binary image

Closed image, returned as a grayscale image or binary image. J has the same class as input image I.

Compatibility Considerations

imclose pads image border

Behavior changed in R2017a

Starting in R2017a, imclose pads the input image border by half the size of the structuring element. Padding the image removes border artifacts when there are foreground pixels near the boundary of the input image.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• imclose supports the generation of C code (requires MATLAB^® Coder™). Note that if you choose the generic MATLAB Host Computer target platform, imclose generates code that uses a precompiled, platform-specific shared library. Use of a shared library preserves performance optimizations but limits the target platforms for which code can be generated. For more information, see Code Generation Using a Shared Library.

• The input image I must be 2-D or 3-D.

GPU Code Generation

Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Usage notes and limitations:

• The input image I must be 2-D or 3-D.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

Usage notes and limitations:

• gpuArray input must be of type uint8 or logical.

• The structuring element SE must be flat and 2-D.

For more information, see Image Processing on a GPU.