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pythonopencvnumpybinaryjpeg

How to decode jpg image from memory?

I can read a jpg image from disk via PIL, Python OpenCV, etc. into a numpy array via some built-in functions such as (in the case of OpenCV) arr= cv2.imread(filename).

But how do I decode a jpg in binary format directly from memory?

Use case: I want to put a jpg image into a database in binary format and then read it from the db into memory and decode it to a numpy array.

Is this possible?

Solution

  • Assuming that you are storing the image data in your db as a string, you first need to construct a numpy array from that string that can later be converted to an image using cv2.imdecode. For example:

    img = cv2.imdecode(np.fromstring(img_data, dtype=np.uint8), cv2.IMREAD_UNCHANGED)