Move in face detection sample + test

Author: Jerjou Cheng

vision/api/face_detection/README.md

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+Python face detection [Vision API](https://cloud.google.com/vision/) example.
+See the [tutorial](https://cloud.google.com/vision/docs/face-tutorial).

vision/api/face_detection/faces.py

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+#!/usr/bin/env python
+
+# Copyright 2015 Google, Inc
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Draws squares around faces in the given image."""
+
+import argparse
+import base64
+
+from googleapiclient import discovery
+from oauth2client.client import GoogleCredentials
+from PIL import Image
+from PIL import ImageDraw
+
+
+# [START get_vision_service]
+DISCOVERY_URL = ('https://{api}.googleapis.com/$discovery/rest?'
+                 'version={apiVersion}')
+
+
+def get_vision_service():
+    credentials = GoogleCredentials.get_application_default()
+    return discovery.build('vision', 'v1', credentials=credentials,
+                           discoveryServiceUrl=DISCOVERY_URL)
+# [END get_vision_service]
+
+
+def detect_face(face_file, max_results=4):
+    """Uses the Vision API to detect faces in the given file.
+
+    Args:
+        face_file: A file-like object containing an image with faces.
+
+    Returns:
+        An array of dicts with information about the faces in the picture.
+    """
+    image_content = face_file.read()
+    batch_request = [{
+        'image': {
+            'content': base64.b64encode(image_content).decode('utf-8')
+            },
+        'features': [{
+            'type': 'FACE_DETECTION',
+            'maxResults': max_results,
+            }]
+        }]
+
+    service = get_vision_service()
+    request = service.images().annotate(body={
+        'requests': batch_request,
+        })
+    response = request.execute()
+
+    return response['responses'][0]['faceAnnotations']
+
+
+def highlight_faces(image, faces, output_filename):
+    """Draws a polygon around the faces, then saves to output_filename.
+
+    Args:
+      image: a file containing the image with the faces.
+      faces: a list of faces found in the file. This should be in the format
+          returned by the Vision API.
+      output_filename: the name of the image file to be created, where the
+          faces have polygons drawn around them.
+    """
+    im = Image.open(image)
+    draw = ImageDraw.Draw(im)
+
+    for face in faces:
+        box = [(v.get('x', 0.0), v.get('y', 0.0))
+               for v in face['fdBoundingPoly']['vertices']]
+        draw.line(box + [box[0]], width=5, fill='#00ff00')
+
+    im.save(output_filename)
+
+
+def main(input_filename, output_filename, max_results):
+    with open(input_filename, 'rb') as image:
+        faces = detect_face(image, max_results)
+        print('Found {} face{}'.format(
+            len(faces), '' if len(faces) == 1 else 's'))
+
+        print('Writing to file {}'.format(output_filename))
+        # Reset the file pointer, so we can read the file again
+        image.seek(0)
+        highlight_faces(image, faces, output_filename)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        description='Detects faces in the given image.')
+    parser.add_argument(
+        'input_image', help='the image you\'d like to detect faces in.')
+    parser.add_argument(
+        '--out', dest='output', default='out.jpg',
+        help='the name of the output file.')
+    parser.add_argument(
+        '--max-results', dest='max_results', default=4,
+        help='the max results of face detection.')
+    args = parser.parse_args()
+
+    main(args.input_image, args.output, args.max_results)

vision/api/face_detection/faces_test.py

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+# Copyright 2016, Google, Inc.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+from faces import main
+from PIL import Image
+
+
+def test_main(resource, tmpdir):
+    out_file = os.path.join(tmpdir.dirname, 'face-output.jpg')
+    in_file = resource('face-input.jpg')
+
+    # Make sure there isn't already a green box
+    im = Image.open(in_file)
+    pixels = im.getdata()
+    greens = sum(1 for (r, g, b) in pixels if r == 0 and g == 255 and b == 0)
+    assert greens < 1
+
+    main(in_file, out_file, 10)
+
+    # Make sure there now is some green drawn
+    im = Image.open(out_file)
+    pixels = im.getdata()
+    greens = sum(1 for (r, g, b) in pixels if r == 0 and g == 255 and b == 0)
+    assert greens > 10

vision/api/face_detection/requirements.txt

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+google-api-python-client==1.5.0
+Pillow==3.1.1