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samples/python/lappyr.py

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+#!/usr/bin/env python
+
+''' An example of Laplacian Pyramid construction and merging.
+
+Level : Intermediate
+
+Usage : python lappyr.py [<video source>]
+
+References:
+  http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.54.299
+
+Alexander Mordvintsev 6/10/12
+'''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
+import numpy as np
+import cv2 as cv
+
+import video
+from common import nothing, getsize
+
+def build_lappyr(img, leveln=6, dtype=np.int16):
+    img = dtype(img)
+    levels = []
+    for _i in xrange(leveln-1):
+        next_img = cv.pyrDown(img)
+        img1 = cv.pyrUp(next_img, dstsize=getsize(img))
+        levels.append(img-img1)
+        img = next_img
+    levels.append(img)
+    return levels
+
+def merge_lappyr(levels):
+    img = levels[-1]
+    for lev_img in levels[-2::-1]:
+        img = cv.pyrUp(img, dstsize=getsize(lev_img))
+        img += lev_img
+    return np.uint8(np.clip(img, 0, 255))
+
+
+def main():
+    import sys
+
+    try:
+        fn = sys.argv[1]
+    except:
+        fn = 0
+    cap = video.create_capture(fn)
+
+    leveln = 6
+    cv.namedWindow('level control')
+    for i in xrange(leveln):
+        cv.createTrackbar('%d'%i, 'level control', 5, 50, nothing)
+
+    while True:
+        _ret, frame = cap.read()
+
+        pyr = build_lappyr(frame, leveln)
+        for i in xrange(leveln):
+            v = int(cv.getTrackbarPos('%d'%i, 'level control') / 5)
+            pyr[i] *= v
+        res = merge_lappyr(pyr)
+
+        cv.imshow('laplacian pyramid filter', res)
+
+        if cv.waitKey(1) == 27:
+            break
+
+    print('Done')
+
+
+if __name__ == '__main__':
+    print(__doc__)
+    main()
+    cv.destroyAllWindows()