Python resize image and send to google vision function

问题

Since google vision has some restrictions on input image size, I want to first resize input image and then use the detect_labels() function.

Here's their sample code

def detect_labels(path):
"""Detects labels in the file."""
vision_client = vision.Client()

with io.open(path, 'rb') as image_file:
    content = image_file.read()

image = vision_client.image(content=content)

labels = image.detect_labels()
print('Labels:')

for label in labels:
    print(label.description)

they use io to open the image file. I wonder in this way, how to resize the image in memory and then call detect_labels() ?

回答1:

You can resize the image via PIL/Pillow and then pass it to the client:

replace

with io.open(path, 'rb') as image_file:
    content = image_file.read()

with

# Warning: untested code, may require some fiddling
import Image, StringIO

img = Image.open(path)
img.thumbnail((512, 512))
buffer = StringIO.StringIO()
img.save(buffer, "PNG")

content = buffer.getvalue()

回答2:

Code for python3:

Credits : @kristaps

import io
from PIL import Image
img = Image.open(path)
img.thumbnail((512, 512))
buffer = io.BytesIO()
img.save(buffer, "JPEG")
content = buffer.getvalue()

来源：https://stackoverflow.com/questions/45176829/python-resize-image-and-send-to-google-vision-function