Python OpenCV将图像转换为字节字符串?

2022-01-09 00:00:00 python opencv binary image

问题描述

我正在使用 PyOpenCV.如何在没有临时文件和 imwrite 的情况下将 cv2 图像(numpy)转换为二进制字符串以写入 MySQL db?

I'm working with PyOpenCV. How to convert cv2 image (numpy) to binary string for writing to MySQL db without a temporary file and imwrite?

我用谷歌搜索了它，但什么也没找到......

I googled it but found nothing...

我正在尝试 imencode，但它不起作用.

I'm trying imencode, but it doesn't work.

capture = cv2.VideoCapture(url.path)
capture.set(cv2.cv.CV_CAP_PROP_POS_MSEC, float(url.query))
self.wfile.write(cv2.imencode('png', capture.read()))

错误:

  File "server.py", line 16, in do_GET
  self.wfile.write(cv2.imencode('png', capture.read()))
  TypeError: img is not a numerical tuple

帮助别人！

解决方案

如果你有一个图像 img(这是一个 numpy 数组)，你可以使用以下方法将其转换为字符串:

If you have an image img (which is a numpy array) you can convert it into string using:

>>> img_str = cv2.imencode('.jpg', img)[1].tostring()
>>> type(img_str)
 'str'

现在您可以轻松地将图像存储在数据库中，然后使用以下方法恢复它:

Now you can easily store the image inside your database, and then recover it by using:

>>> nparr = np.fromstring(STRING_FROM_DATABASE, np.uint8)
>>> img = cv2.imdecode(nparr, cv2.CV_LOAD_IMAGE_COLOR)

您需要将 STRING_FROM_DATABASE 替换为包含对包含图像的数据库的查询结果的变量.

where you need to replace STRING_FROM_DATABASE with the variable that contains the result of your query to the database containing the image.

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