为什么不按照应有的方式在这里进行减量？(Why doesn't decrementation work here the way it should?)

我很确定我犯了一个愚蠢的错误，但我似乎找不到它已经有一段时间了。

我（成功）加载一些图像，将它们转换为灰度，然后打印到黑白。然后我想制作一个方法，通过测量每个像素的平均颜色值（0 ... 255）来评估每一行像素，并给出第一个低于某个阈值的行号。它有效，但扩展方法从底部做同样的事情却没有。这是它的外观：

t_thresh_hor = 210.0 def core_text_loc(image): height, width = image.shape height = height - 1 # to adjust for starting with 0 width = width - 1 # to adjust for starting with 0 top_trim = 0 bot_trim = height i = 0 while i < height and top_trim == 0: row = image[i, 0:-1] i = i + 1 if numpy.mean(row) < t_thresh_hor: top_trim = i # here it stops working i = height while i > 0 and bot_trim == height: row = image[height, 0:-1] if numpy.mean(row) < t_thresh_hor: bot_trim = i i = i - 1 return(top_trim, bot_trim)

我知道阈值是正确的（当我手动访问特定行时有效），但bot_trim总是返回图片的高度，这意味着它在第一次迭代时停止（？）。我做错了什么？

编辑： 示例案例：我在两张图片上测试它：第一个是4724x3177，输出是：top_trim：1216（正确）bot_trim：4723（应该是≈4400）第二个one4705 3177 top_trim：315（正确）bot_trim：4704 （应该是≈4400）

I am pretty sure I've made a silly mistake, but I cannot seem to find it for quite some time.

I (successfully) load some images, convert them to grayscale and thresh to b&w. Then I wanted to make a method that evaluates each row of pixels by measuring its avg color value (0…255) and give me the row number of the first one that is below a certain threshold. It works, but expanding the method to do the same thing from the bottom does not. Here's how it looks:

t_thresh_hor = 210.0 def core_text_loc(image): height, width = image.shape height = height - 1 # to adjust for starting with 0 width = width - 1 # to adjust for starting with 0 top_trim = 0 bot_trim = height i = 0 while i < height and top_trim == 0: row = image[i, 0:-1] i = i + 1 if numpy.mean(row) < t_thresh_hor: top_trim = i # here it stops working i = height while i > 0 and bot_trim == height: row = image[height, 0:-1] if numpy.mean(row) < t_thresh_hor: bot_trim = i i = i - 1 return(top_trim, bot_trim)

I know the threshold is correct (works when I manually access a specific line), but bot_trim always returns the height of the picture, meaning it stopped at the first iteration (?). What have I done wrong?

EDIT: Sample case: I am testing it on two pictures: first one is 4724x3177, and the output is: top_trim: 1216 (correct) bot_trim: 4723 (should be ≈ 4400) second one4705 3177 top_trim: 315 (correct) bot_trim: 4704 (should be ≈ 4400)