计算numpy数组的边界框

Question

我正在努力解决一个简单的问题.我有一个numpy数组的形式:

[[[ 1152.07507324   430.84799194]
  [ 4107.82910156   413.95199585]
  [ 4127.64941406  2872.32006836]
  [ 1191.71643066  2906.11206055]]]

我想计算边界框,意思是,我想要最左边,最顶部,最右边和最底部的点.

这应该是一个正确的解决方案

[[[ 1152.07507324   413.95199585]
  [ 4127.64941406   413.95199585]
  [ 4127.64941406  2906.11206055]
  [ 1152.07507324  2906.11206055]]]

我开发了一个令人讨厌的功能,但是我对它非常不满意,因为它不是真正的pythonic/numpyic

def bounding_box(iterable):
    minimum_x = min(iterable[0], key=lambda x:x[0])[0]
    maximum_x = max(iterable[0], key=lambda x:x[0])[0]
    minimum_y = min(iterable[0], key=lambda x:x[1])[1]
    maximum_y = max(iterable[0], key=lambda x:x[1])[1]

    return numpy.array([[(minimum_x, minimum_y), (maximum_x, minimum_y), (maximum_x, maximum_y), (minimum_x, maximum_y)]], dtype=numpy.float32)

你有任何想法如何优化上面的功能,也许使用numpy内置？

Answer 1

使用numpy.min和numpy.max内置:

def bounding_box(iterable):
    min_x, min_y = numpy.min(iterable[0], axis=0)
    max_x, max_y = numpy.max(iterable[0], axis=0)
    return numpy.array([(min_x, min_y), (max_x, min_y), (max_x, max_y), (min_x, max_y)])