feat: 切换后端至PaddleOCR-NCNN，切换工程为CMake

1.项目后端整体迁移至PaddleOCR-NCNN算法，已通过基本的兼容性测试
2.工程改为使用CMake组织，后续为了更好地兼容第三方库，不再提供QMake工程
3.重整权利声明文件，重整代码工程，确保最小化侵权风险

Log: 切换后端至PaddleOCR-NCNN，切换工程为CMake
Change-Id: I4d5d2c5d37505a4a24b389b1a4c5d12f17bfa38c

3rdparty/opencv-4.5.4/samples/python/facedetect.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python
+
+'''
+face detection using haar cascades
+
+USAGE:
+    facedetect.py [--cascade <cascade_fn>] [--nested-cascade <cascade_fn>] [<video_source>]
+'''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+
+import numpy as np
+import cv2 as cv
+
+# local modules
+from video import create_capture
+from common import clock, draw_str
+
+
+def detect(img, cascade):
+    rects = cascade.detectMultiScale(img, scaleFactor=1.3, minNeighbors=4, minSize=(30, 30),
+                                     flags=cv.CASCADE_SCALE_IMAGE)
+    if len(rects) == 0:
+        return []
+    rects[:,2:] += rects[:,:2]
+    return rects
+
+def draw_rects(img, rects, color):
+    for x1, y1, x2, y2 in rects:
+        cv.rectangle(img, (x1, y1), (x2, y2), color, 2)
+
+def main():
+    import sys, getopt
+
+    args, video_src = getopt.getopt(sys.argv[1:], '', ['cascade=', 'nested-cascade='])
+    try:
+        video_src = video_src[0]
+    except:
+        video_src = 0
+    args = dict(args)
+    cascade_fn = args.get('--cascade', "data/haarcascades/haarcascade_frontalface_alt.xml")
+    nested_fn  = args.get('--nested-cascade', "data/haarcascades/haarcascade_eye.xml")
+
+    cascade = cv.CascadeClassifier(cv.samples.findFile(cascade_fn))
+    nested = cv.CascadeClassifier(cv.samples.findFile(nested_fn))
+
+    cam = create_capture(video_src, fallback='synth:bg={}:noise=0.05'.format(cv.samples.findFile('samples/data/lena.jpg')))
+
+    while True:
+        _ret, img = cam.read()
+        gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
+        gray = cv.equalizeHist(gray)
+
+        t = clock()
+        rects = detect(gray, cascade)
+        vis = img.copy()
+        draw_rects(vis, rects, (0, 255, 0))
+        if not nested.empty():
+            for x1, y1, x2, y2 in rects:
+                roi = gray[y1:y2, x1:x2]
+                vis_roi = vis[y1:y2, x1:x2]
+                subrects = detect(roi.copy(), nested)
+                draw_rects(vis_roi, subrects, (255, 0, 0))
+        dt = clock() - t
+
+        draw_str(vis, (20, 20), 'time: %.1f ms' % (dt*1000))
+        cv.imshow('facedetect', vis)
+
+        if cv.waitKey(5) == 27:
+            break
+
+    print('Done')
+
+
+if __name__ == '__main__':
+    print(__doc__)
+    main()
+    cv.destroyAllWindows()