def denoise_pass(self, img, min_size):
        nb_components, labels, stats, centroids = \
            cv.connectedComponentsWithStats(img, connectivity=8)
        sizes = stats[1:, -1]
        nb_components = nb_components - 1
        img2 = np.zeros(labels.shape, dtype=np.uint8)
        for i in range(0, nb_components):
            if sizes[i] >= min_size:
                img2[labels == i + 1] = 255
        return(img2)