imopen

Morphologically open image

Syntax

IM2 = imopen(IM,SE)
IM2 = imopen(IM,NHOOD)
gpuarrayIM2 = imopen(gpuarrayIM,___)

Description

IM2 = imopen(IM,SE) performs morphological opening on the grayscale or binary image IM with the structuring element SE. The argument SE must be a single structuring element object, as opposed to an array of objects. The morphological open operation is an erosion followed by a dilation, using the same structuring element for both operations.

This function supports code generation (see Tips).

IM2 = imopen(IM,NHOOD) performs opening with the structuring element strel(NHOOD), where NHOOD is an array of 0's and 1's that specifies the structuring element neighborhood.

gpuarrayIM2 = imopen(gpuarrayIM,___) performs the operation on a graphics processing unit (GPU) with the structuring element strel(NHOOD), if NHOOD is an array of 0s and 1s that specifies the structuring element neighborhood, or strel(gather(NHOOD)) if NHOOD is a gpuArray object that specifies the structuring element neighborhood. This syntax requires the Parallel Computing Toolbox™.

Class Support

IM can be any numeric or logical class and any dimension, and must be nonsparse. If IM is logical, then SE must be flat.

gpuarrayIM must be a gpuArray of type uint8 or logical. When used with a gpuarray, the structuring element must be flat and two-dimensional.

The output has the same class as the input.

Examples

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Morphologically Open Image with a Disk-shaped Structuring Element

Read the image into the MATLAB® workspace and display it.

original = imread('snowflakes.png');
figure, imshow(original);

Create a disk-shaped structuring element with a radius of 5 pixels.

se = strel('disk',5);

Remove snowflakes having a radius less than 5 pixels by opening it with the disk-shaped structuring element.

afterOpening = imopen(original,se);
figure, imshow(afterOpening,[]);

Morphologically Open Image with Disk-shaped Structuring Element on a GPU

Read an image.

 original = imread('snowflakes.png');

Create a disk-shaped structuring element.

se = strel('disk',5);

Morphologically open the image on a GPU, using a gpuArray object, and display the images.

afterOpening = imopen(gpuArray(original),se);
figure, imshow(original), figure, imshow(afterOpening,[])

More About

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Tips

  • This function supports the generation of C code using MATLAB Coder™. Note that if you choose the generic MATLAB Host Computer target platform, the function 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.

    When generating code, the image input argument, IM, must be 2-D or 3-D and the structuring element input argument, SE, must be a compile-time constant.

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