在python中将大图像文件作为数组读取 [英] read big image file as an array in python

问题描述

有谁知道如何使用python打开大图像文件？
我尝试使用ipython通过Windows命令提示符打开图像文件（大约2 GB），但每次将图像值更改为数组后都会崩溃。

Does anyone know how to open a large imagery file using python? I tried to open an imagery file (about 2 GB) through windows command prompt using ipython, but it crashes every time after I change image values into an array.

我的笔记本电脑是window7-64bit，配备4GB内存和Intel（R）Core（TM）i7-2860 QM CPU。

My laptop is window7-64bit with 4GB ram and Intel(R) Core(TM) i7-2860 QM CPU.

错误消息是：python.exe已停止工作问题导致程序无法正常工作。如果解决方案可用，Windows将关闭程序并通知您

The error message is: python.exe has stopped working A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available

这是我的代码。

import Image
import numpy as num
im=Image.open('myimage.tif')
imarray=num.array(im)

推荐答案

你有多少RAM？你需要超过2GB的RAM来存储2-gig图像。我不知道 Image 在存储图像方面有多高效，但是字节列表对列表中的每个元素使用四个字节的空间，这样你就可以燃烧超过8GB的（虚拟）内存......而且需要很多耐心。 编辑：由于你只有4（或3）GB可以使用，这几乎肯定是你的问题。

How much RAM do you have? You'll need quite a bit more than 2GB of RAM to store a 2-gig image. I don't know how efficient Image is at storing images, but a list of bytes uses four bytes of space for each element in the list, so you'll burn more than 8GB of (virtual) memory... and a lot of patience. Since you only have 4 (or 3) GB to play with, this is almost certainly your problem.

但你为什么要尝试将它转换为数字数组？使用 Image.open 返回的 im 对象的方法，如 PIL教程。

But why are you trying to convert it to a numeric array? Use the methods of the im object returned by Image.open, as in the PIL Tutorial.

我不知道您正在使用图像做什么，但也许您可以在不读取内存中的整个图像的情况下执行此操作，或者至少不将整个对象转换为 numpy 数组。如果可能的话，一点一点地读取它以避免炸毁你的机器：读取python生成器，并查看 Image.getdata（）方法，该方法返回一个像素值的图像一次。

I don't know what you're doing with the image, but perhaps you can do it without reading the entire image in memory, or at least without converting the entire object into a numpy array. Read it bit by bit if possible to avoid blowing up your machine: Read up on python generators, and see the Image.getdata() method, which returns your image one pixel value at a time.

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