def meas_pruning_ratio(num_blobs_orig, num_blobs_after_pruning, num_blobs_next):
    """Measure blob pruning ratio.
    
    Args:
        num_blobs_orig: Number of original blobs, before pruning.
        num_blobs_after_pruning: Number of blobs after pruning.
        num_blobs_next: Number of a blobs in an adjacent segment, presumably 
            of similar size as that of the original blobs.
    
    Returns:
        Pruning ratios as a tuple of the original number of blobs, 
        blobs after pruning to original, and blobs after pruning to 
        the next region.
    """
    ratios = None
    if num_blobs_next > 0 and num_blobs_orig > 0:
        # calculate pruned:original and pruned:adjacent blob ratios
        print("num_blobs_orig: {}, blobs after pruning: {}, num_blobs_next: {}"
              .format(num_blobs_orig, num_blobs_after_pruning, num_blobs_next))
        ratios = (num_blobs_orig, num_blobs_after_pruning / num_blobs_orig, 
                  num_blobs_after_pruning / num_blobs_next)
    return ratios