pythonimage-processingopencvimage-morphology

How to get rid of points in bw image and be left with connected pixels?

I have the following image (image is fully black, don't mind the border)

enter image description here

I want to be left only with the (1 pixel-wide) line, and be rid of all the points (some of which are actually a couple of pixels).

I know this is rather easy, but i am out of ideas for now :(

What I have tried:

a morphology operation for opening (erode + dilate) - left me with either nothing or the same

blob detection - doing this would maybe work after dilation, but it crashes with no error (windows exception), and I have no time to debug opencv.

would love any idea that works.

Solution

  • I ended up doing the following, just to get done with it. I am sure something smarter could have been done:

        thread_defect_mask_clean = thread_defect_mask_noisy.copy()
    ret, connected_components_labels = cv2.connectedComponents(thread_defect_mask_noisy.astype('uint8'), connectivity=8)
    for label in range(1, ret):
        label_count = np.count_nonzero(label == connected_components_labels)
        if label_count < self._min_thread_defect_size:
            thread_defect_mask_clean[label == connected_components_labels] = 0

    This counts the size of each connected component, and enforces a threshold (5 here)