Question

我想设置从rbpi到服务器的图像流。

所以我想在http://picamera.readthedocs.io/en/release-1.12/recipes1.html#streaming-capture中设置一个网络流。

这很好用，但现在我想保存捕获的图像。

- ＆GT; （修改了服务器脚本）

import io
import socket
import struct
from PIL import Image

# Start a socket listening for connections on 0.0.0.0:8000 (0.0.0.0 means
# all interfaces)
server_socket = socket.socket()
server_socket.bind(('0.0.0.0', 8000))
server_socket.listen(0)

# Accept a single connection and make a file-like object out of it
connection = server_socket.accept()[0].makefile('rb')
try:
    while True:
        # Read the length of the image as a 32-bit unsigned int. If the
        # length is zero, quit the loop
        image_len = struct.unpack('<L', connection.read(struct.calcsize('<L')))[0]
        if not image_len:
            break
        # Construct a stream to hold the image data and read the image
        # data from the connection
        image_stream = io.BytesIO()
        image_stream.write(connection.read(image_len))
        # Rewind the stream, open it as an image with PIL and do some
        # processing on it
        image_stream.seek(0)
        image = Image.open(image_stream)
        print('Image is %dx%d' % image.size)
        image.verify()
        print('Image is verified')
        im = Image.new("RGB", (640,480), "black") #the saving part
        im = image.copy()
        im.save("./img/test.jpg","JPEG")
finally:
    connection.close()
    server_socket.close()

但它返回我的错误代码：

Traceback (most recent call last):
  File "stream.py", line 33, in <module>
    im = image.copy()
  File "/usr/lib/python2.7/dist-packages/PIL/Image.py", line 781, in copy
    self.load()
  File "/usr/lib/python2.7/dist-packages/PIL/ImageFile.py", line 172, in load
    read = self.fp.read
AttributeError: 'NoneType' object has no attribute 'read'

我该如何解决这个问题？

Answer 1

我没有树莓派，但决定看看我是否可以重现这个问题。此外，对于输入我刚刚在磁盘上创建了一个图像文件，以消除所有套接字的东西。果然我遇到了与你遇到的完全相同的错误。（注意： IMO您应该自己进行此简化并发布说明问题的MCVE（请参阅SO帮助中心内的How to create a Minimal, Complete, and Verifiable example）。

为了解决问题，我在image.load()语句后立即调用了Image.open()方法并开始工作。不仅错误消失了，而且输出文件似乎也很好。

这是我的简单测试代码，其中包含修复程序：

import io
import os
from PIL import Image

image_filename = 'pillow_test.jpg'

image_len = os.stat(image_filename).st_size
image_stream = io.BytesIO()
with open(image_filename, 'rb') as image_file:
    image_stream.write(image_file.read(image_len))
image_stream.seek(0)
image = Image.open(image_stream)
image.load()  # <======================== ADDED LINE
print('Image is %dx%d' % image.size)
image.verify()
print('Image is verified')
im = Image.new("RGB", (640,480), "black") #the saving part
im = image.copy()
im.save("pillow_test_out.jpg","JPEG")
print('image written')

线索是来自PIL.Image.open() load()函数的pillow documentation的这段话：

这是一个懒惰的操作;此函数标识文件，但文件在您尝试之前，不会从文件中读取实际图像数据处理数据（或调用image.verify()方法）。

强调我的。您会认为with open("input.txt", 'r') as file: line = file.read() line = line.split() count = 0 output = open("output.txt", 'w') for i in line: output.write(i) output.write(" ") count+=1 if count == 9: output.write("\n") count = 0 output.close()会使这不必要，因为似乎验证“文件”需要加载图像数据以检查其内容（根据该方法自己的documentation，它声称它“验证文件的内容“）。我猜这可能是一个错误，你应该报告它。

枕头属性错误

1 个答案: