locator.py 文件源码

def _locate(segmented, offset=None):
    """Inspired from: https://goo.gl/HYPrR1"""
    # clean invalid patterns from the mask
    segmented = process_mask(segmented)

    # CV_RETR_EXTERNAL to only get external contours.
    _, contours, hierarchy = cv2.findContours(segmented.copy(),
                                              cv2.RETR_CCOMP,
                                              cv2.CHAIN_APPROX_SIMPLE)

    # Note: points are represented as (col, row)-tuples apparently
    transform = identity
    if offset is not None:
        col_off, row_off = offset
        transform = affine_transform(delta_x=col_off, delta_y=row_off)
    components = []
    if len(contours) > 0:
        top_index = 0
        tops_remaining = True
        while tops_remaining:
            exterior = contours[top_index][:, 0, :].tolist()

            interiors = []
            # check if there are childs and process if necessary
            if hierarchy[0][top_index][2] != -1:
                sub_index = hierarchy[0][top_index][2]
                subs_remaining = True
                while subs_remaining:
                    interiors.append(contours[sub_index][:, 0, :].tolist())

                    # check if there is another sub contour
                    if hierarchy[0][sub_index][0] != -1:
                        sub_index = hierarchy[0][sub_index][0]
                    else:
                        subs_remaining = False

            # add component tuple to components only if exterior is a polygon
            if len(exterior) > 3:
                polygon = Polygon(exterior, interiors)
                polygon = transform(polygon)
                if polygon.is_valid:  # some polygons might be invalid
                    components.append(polygon)
                else:
                    print (explain_validity(polygon))

            # check if there is another top contour
            if hierarchy[0][top_index][0] != -1:
                top_index = hierarchy[0][top_index][0]
            else:
                tops_remaining = False

    del contours
    del hierarchy
    return components