cv2.boundingRect格式文档

为什么会产生这种代码 (1, 1, 1, 1) cv2.boundingRect 以格式返回rect x,y,w,h 但是为什么呢 w,h 在这种情况下不是零吗?

import cv2
import numpy as np

cv2.__version__
'4.4.0'

np.__version__
'1.19.2'

a = np.ones((8,2))
x, y, w, h = cv2.boundingRect(a.astype(np.float32))

绑定文档中没有太多信息:

def boundingRect(array): # real signature unknown; restored from __doc__
    """
    boundingRect(array) -> retval
    .   @brief Calculates the up-right bounding rectangle of a point set or non-zero pixels of gray-scale image.
    .   
    .   The function calculates and returns the minimal up-right bounding rectangle for the specified point set or
    .   non-zero pixels of gray-scale image.
    .   
    .   @param array Input gray-scale image or 2D point set, stored in std::vector or Mat.
    """
    pass

更新:

return Rect(xmin, ymin, xmax - xmin + 1, ymax - ymin + 1);