morphologyEx

Usage

Performs advanced morphological transformations, such as opening, closing, gradient, top-hat, and black-hat operations, using erosion and dilation as basic operations. It is widely used in noise removal, edge detection, and structure extraction in image processing.

Interface

void morphologyEx(InputArray src, OutputArray dst, int op, InputArray kernel, Point anchor = Point(-1, -1), int iterations = 1, int borderType = BORDER_CONSTANT, const Scalar& borderValue = morphologyDefaultBorderValue());

Parameters

Parameter	Description	Value Range	Input/Output
src	Input image.	Not null	Input
dst	Output image.	Mat class	Input
op	Morphological operation type.	MORPH_OPEN MORPH_CLOSE MORPH_GRADIENT MORPH_TOPHAT MORPH_BLACKHAT	Input
kernel	Morphological kernel.	Not null	Input
anchor	Anchor position.	(-1, -1) by default, indicating the kernel center	Input
iterations	Number of iterations.	(1, inf)	Input
borderType	Border type.	BORDER_CONSTANT BORDER_REPLICATE BORDER_REFLECT, etc.	Input
borderValue	Constant value used to fill the border (valid only for a constant border).	(-inf, inf)	Input

Example

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;

int main() {
    // Read the image.
    Mat src = imread("input.jpg", IMREAD_GRAYSCALE);
    if (src.empty()) {
        std::cerr << "Failed to load the image!" << std::endl;
        return -1;
    }

    // Define the morphological kernel.
    Mat kernel = getStructuringElement(MORPH_RECT, Size(5, 5));

    // Perform opening (erosion and then dilation).
    Mat dst;
    morphologyEx(src, dst, MORPH_OPEN, kernel);

    // Display the result.
    imshow("Original image", src);
    imshow("Image after processing", dst);
    waitKey(0);

    return 0;
}

Parent topic: Interface Definition