image.py 文件源码

def find_contours(self, min_area=0.0, max_area=np.inf):
        """Returns a list of connected components with an area between
        min_area and max_area.
        Parameters
        ----------
        min_area : float
            The minimum area for a contour
        max_area : float
            The maximum area for a contour
        Returns
        -------
        :obj:`list` of :obj:`Contour`
            A list of resuting contours
        """
        # get all contours (connected components) from the binary image
        _, contours, hierarchy = cv2.findContours(
            self.data.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
        num_contours = len(contours)
        kept_contours = []

        # find which contours need to be pruned
        for i in range(num_contours):
            area = cv2.contourArea(contours[i])
            logging.debug('Contour %d area: %.3f' % (len(kept_contours), area))
            if area > min_area and area < max_area:
                boundary_px = contours[i].squeeze()
                boundary_px_ij_swapped = np.zeros(boundary_px.shape)
                boundary_px_ij_swapped[:, 0] = boundary_px[:, 1]
                boundary_px_ij_swapped[:, 1] = boundary_px[:, 0]
                kept_contours.append(
                    Contour(
                        boundary_px_ij_swapped,
                        area=area,
                        frame=self._frame))

        return kept_contours