sample negative images

05_draw_bbox.py

@@ -0,0 +1,76 @@
+'''
+We're gonna use the bbox info from OSM to draw a box around the pitch, we
+will use this box to better train our ML algo.
+'''
+
+from utils.geo import WAYS_DATA_FILENAME
+import cv2
+import json
+import math
+import os
+
+image_width = 1280
+image_height = 1280
+
+def get_rectangle(bounds):
+    # This converts a latitude delta into an image delta. For USA, at zoom
+    # level 19, we know that we have 0.21 meters/pixel. So, an image is showing
+    # about 1280 pixels * 0.21 meters/pixel = 268.8 meters.
+    # On the other hand we know that at the same angle, a degress in latlon is:
+    # https://en.wikipedia.org/wiki/Latitude
+    # latitude = 111,132 m
+    # longitude = 78,847 m
+    # Finally, we add 5% to make sure the feature is contained within the
+    # rectangle (from what we see, the bbox are tight around the feature)
+    latitude_factor  = 1.05 * 111132.0 / 0.21
+    longitude_factor = 1.05 * 78847.0 / 0.21
+
+    # Feature size
+    feature_width = longitude_factor * math.fabs(bounds[1] - bounds[3])
+    feature_height = latitude_factor * math.fabs(bounds[0] - bounds[2])
+    if feature_width > image_width or feature_height > image_height:
+        print '** Warning ** The feature is bigger than the image.'
+
+    # CV params (int required)
+    x = int((image_width / 2) - (feature_width / 2))
+    y = int((image_height / 2) - (feature_height / 2))
+    w = int(feature_width)
+    h = int(feature_height)
+    if w <= 25 or h <= 25:
+        print '** Warning ** This image has very narrow bounds.'
+        print bounds
+        print x, y, w, h
+    if x == 0 or y == 0 or w == 0 or h == 0:
+        print '** Warning ** There is something wrong with this image bounds.'
+        print bounds
+        print x, y, w, h
+    return x, y, w, h
+
+# We need the elements
+print 'Loading %s...' % WAYS_DATA_FILENAME
+with open(WAYS_DATA_FILENAME, 'r') as f:
+    ways_data = json.load(f)
+
+image_files = [f for f in os.listdir('satellite') if f.endswith('.png')]
+
+for image_file in image_files:
+    print 'Processing %s...' % image_file
+    # The ID is between the last underscore and the extension dot
+    # For example: pitch_volleyball_268478401.png -> 268478401
+    way_id = image_file[image_file.rfind('_') + 1:image_file.find('.')]
+    bounds = ways_data[way_id]['bounds']
+
+    # Add a rectangle with the feature
+    x, y, w, h = get_rectangle(bounds=bounds)
+    img = cv2.imread(os.path.join('satellite', image_file))
+    cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
+    cv2.imwrite(os.path.join('satellite/rectangle', image_file), img)
+
+    # Generate a grayscale version
+    img_gray = cv2.imread(os.path.join('satellite', image_file), 0)
+    cv2.imwrite(os.path.join('satellite/gray', image_file), img_gray)
+
+# To show the image
+# cv2.imshow('img',img)
+# cv2.waitKey(0)
+# cv2.destroyAllWindows()

06_get_negatives.py

@@ -0,0 +1,58 @@
+'''
+Let's download a few negative images to train the algo.
+
+Usage:
+    python 06_get_negatives.py [-h] [--count COUNT]
+
+    optional arguments:
+      -h, --help     show this help message and exit
+      --count COUNT  The total number of negative images to download.
+'''
+
+from random import shuffle
+from utils.geo import ELEMENTS_FILENAME
+from utils.mapbox_static import MapboxStatic
+import argparse
+import json
+import random
+
+parser = argparse.ArgumentParser(add_help=True)
+
+parser.add_argument('--count',
+    type=int, default=5,
+    help='The total number of negative images to download.')
+
+args = vars(parser.parse_args())
+count = args.get('count')
+print 'We are gonna download %d negative images' % count
+
+# We need the elements
+print 'Loading %s...' % ELEMENTS_FILENAME
+with open(ELEMENTS_FILENAME, 'r') as f:
+    elements = json.load(f)
+
+# Randomize elements list to make sure we don't download all pics from the
+# same sample. Then cut it.
+shuffle(elements)
+
+# Now we're gonna download the satellite images for these locations
+mapbox_static = MapboxStatic(
+    namespace='negative',
+    root_folder='satellite/negative')
+
+total_downloaded = 0
+for element in elements:
+    if total_downloaded >= count:
+            break
+    if element.get('type') != 'node':
+        continue
+    # Move the latlon a random amount, random() is in the range [0.0, 1.0)
+    target_lat = element.get('lat') + (random.random() - 0.5)
+    target_lon = element.get('lon') + (random.random() - 0.5)
+    url = mapbox_static.get_url(latitude=target_lat, longitude=target_lon)
+    print url
+    success = mapbox_static.download_tile(
+        element_id=element.get('id'),
+        url=url)
+    if success:
+        total_downloaded += 1

Makefile

@@ -29,3 +29,7 @@ step4:
 step5:
 	# Draw the bbox on the test files
 	python 05_draw_bbox.py
+
+step6:
+	# Get some random images
+	python 06_get_negatives.py --count 25

satellite/.gitignore

@@ -0,0 +1,2 @@
+gray
+rectangle