refactored BallFinder and live detection demo

scripts/detection_demo.py

@@ -0,0 +1,22 @@
+from __future__ import print_function
+from __future__ import division
+
+import json
+from imagereaders import NaoImageReader, VideoReader
+from finders import BallFinder
+
+
+if __name__ == '__main__':
+    video = VideoReader(0, loop=True)
+    with open('ball_hsv.json') as f:
+        hsv = json.load(f)
+    hsv_lower = tuple(map(hsv.get, ('low_h', 'low_s', 'low_v')))
+    hsv_upper = tuple(map(hsv.get, ('high_h', 'high_s', 'high_v')))
+    finder = BallFinder(hsv_lower, hsv_upper, 5, None)
+    try:
+        while True:
+            frame = video.get_frame()
+            finder.find_colored_ball(frame)
+            finder.visualize(frame)
+    finally:
+        video.close()