CODEWITHSUNDEEP
opencv
Bryanyan
Bryanyan

Reputation: 677

Implementation of Matlab API ordfilt2 in OpenCV

I am translating the code written in Matlab to OpenCV. In Matlab, there is ordfilt2 function. Is there any similar implementation in OpenCV? Thanks

Upvotes: 0

Views: 2593

Answers (3)

user3810074
user3810074

Reputation: 1

dilation = ordfilt2(proj, 5, ones(1,5));  %in matlab

Following is my implementation in opencv, proj is 1D matrix of size (26,1)
Mat dilation = proj.clone(); Mat array = Mat::zeros(5, 1, CV_32FC1);
    for (int i = 0; i < 26; i++)
    {
        (i - 2) < 0 ? array.at<float>(0, 0) = 0 : array.at<float>(0, 0) = proj.at<float>(i - 2, 0);
        (i - 1) < 0 ? array.at<float>(1, 0) = 0 : array.at<float>(1, 0) = proj.at<float>(i - 1, 0);
        (i) < 0 ? array.at<float>(2, 0) = 0 : array.at<float>(2, 0) = proj.at<float>(i, 0);
        (i + 1) >= 26? array.at<float>(3, 0) = 0 : array.at<float>(3, 0) = proj.at<float>(i + 1, 0);
        (i + 2) >= 26? array.at<float>(4, 0) = 0 : array.at<float>(4, 0) = proj.at<float>(i + 2, 0);
        float temp = 0;
        for (int j = 0; j < 5; j++)
        {
            if (temp < array.at<float>(j, 0))
                temp = array.at<float>(j, 0);
        }
        dilation.at<float>(i, 0) = temp;
    }

Upvotes: 0

Bryanyan
Bryanyan

Reputation: 677

I implemented the ordfilt2() in Matlab using erosion or dilation in OpenCV. ordfilt2(A,1,ones(3,3)) in Matlab is erosion function and can be replaced with cv::erode(im, mx, mk,cv::Point(-1,-1),1,BORDER_CONSTANT ); in OpenCV. ordfilt2(A,9,ones(3,3)) in Matlab is dilation and can be replaced with cv::dilate(im, mx, mk,cv::Point(-1,-1),1,BORDER_CONSTANT );.

Upvotes: 1

LovaBill
LovaBill

Reputation: 5139

I don't think there is a general one. Browse here to find if something suits you.

From Matlab help:

B = ordfilt2(A, order, domain) replaces each element in A by the orderth element in the sorted set of neighbors specified by the nonzero elements in domain.

So you have an image A, and your slide a kernel(domain) which sorts pixel values and you pick always one specific order.

OpenCV steps (for a grayscale image):

1) clone image canvas

2) slide on each pixel of the canvas

3) create a vector of a subregion of the same pixel on your image

4) sort the vector

5) set the new image pixel value to the desired vector element.

Upvotes: 0

Related Questions