1 #!/usr/bin/env python 2 3 ''' 4 Video capture sample. 5 6 Sample shows how VideoCapture class can be used to acquire video 7 frames from a camera of a movie file. Also the sample provides 8 an example of procedural video generation by an object, mimicking 9 the VideoCapture interface (see Chess class). 10 11 'create_capture' is a convinience function for capture creation, 12 falling back to procedural video in case of error. 13 14 Usage: 15 video.py [--shotdir <shot path>] [source0] [source1] ...' 16 17 sourceN is an 18 - integer number for camera capture 19 - name of video file 20 - synth:<params> for procedural video 21 22 Synth examples: 23 synth:bg=../data/lena.jpg:noise=0.1 24 synth:class=chess:bg=../data/lena.jpg:noise=0.1:size=640x480 25 26 Keys: 27 ESC - exit 28 SPACE - save current frame to <shot path> directory 29 30 ''' 31 32 import numpy as np 33 from numpy import pi, sin, cos 34 35 import cv2 36 37 # built-in modules 38 from time import clock 39 40 # local modules 41 import common 42 43 class VideoSynthBase(object): 44 def __init__(self, size=None, noise=0.0, bg = None, **params): 45 self.bg = None 46 self.frame_size = (640, 480) 47 if bg is not None: 48 self.bg = cv2.imread(bg, 1) 49 h, w = self.bg.shape[:2] 50 self.frame_size = (w, h) 51 52 if size is not None: 53 w, h = map(int, size.split('x')) 54 self.frame_size = (w, h) 55 self.bg = cv2.resize(self.bg, self.frame_size) 56 57 self.noise = float(noise) 58 59 def render(self, dst): 60 pass 61 62 def read(self, dst=None): 63 w, h = self.frame_size 64 65 if self.bg is None: 66 buf = np.zeros((h, w, 3), np.uint8) 67 else: 68 buf = self.bg.copy() 69 70 self.render(buf) 71 72 if self.noise > 0.0: 73 noise = np.zeros((h, w, 3), np.int8) 74 cv2.randn(noise, np.zeros(3), np.ones(3)*255*self.noise) 75 buf = cv2.add(buf, noise, dtype=cv2.CV_8UC3) 76 return True, buf 77 78 def isOpened(self): 79 return True 80 81 class Chess(VideoSynthBase): 82 def __init__(self, **kw): 83 super(Chess, self).__init__(**kw) 84 85 w, h = self.frame_size 86 87 self.grid_size = sx, sy = 10, 7 88 white_quads = [] 89 black_quads = [] 90 for i, j in np.ndindex(sy, sx): 91 q = [[j, i, 0], [j+1, i, 0], [j+1, i+1, 0], [j, i+1, 0]] 92 [white_quads, black_quads][(i + j) % 2].append(q) 93 self.white_quads = np.float32(white_quads) 94 self.black_quads = np.float32(black_quads) 95 96 fx = 0.9 97 self.K = np.float64([[fx*w, 0, 0.5*(w-1)], 98 [0, fx*w, 0.5*(h-1)], 99 [0.0,0.0, 1.0]]) 100 101 self.dist_coef = np.float64([-0.2, 0.1, 0, 0]) 102 self.t = 0 103 104 def draw_quads(self, img, quads, color = (0, 255, 0)): 105 img_quads = cv2.projectPoints(quads.reshape(-1, 3), self.rvec, self.tvec, self.K, self.dist_coef) [0] 106 img_quads.shape = quads.shape[:2] + (2,) 107 for q in img_quads: 108 cv2.fillConvexPoly(img, np.int32(q*4), color, cv2.LINE_AA, shift=2) 109 110 def render(self, dst): 111 t = self.t 112 self.t += 1.0/30.0 113 114 sx, sy = self.grid_size 115 center = np.array([0.5*sx, 0.5*sy, 0.0]) 116 phi = pi/3 + sin(t*3)*pi/8 117 c, s = cos(phi), sin(phi) 118 ofs = np.array([sin(1.2*t), cos(1.8*t), 0]) * sx * 0.2 119 eye_pos = center + np.array([cos(t)*c, sin(t)*c, s]) * 15.0 + ofs 120 target_pos = center + ofs 121 122 R, self.tvec = common.lookat(eye_pos, target_pos) 123 self.rvec = common.mtx2rvec(R) 124 125 self.draw_quads(dst, self.white_quads, (245, 245, 245)) 126 self.draw_quads(dst, self.black_quads, (10, 10, 10)) 127 128 129 classes = dict(chess=Chess) 130 131 presets = dict( 132 empty = 'synth:', 133 lena = 'synth:bg=../data/lena.jpg:noise=0.1', 134 chess = 'synth:class=chess:bg=../data/lena.jpg:noise=0.1:size=640x480' 135 ) 136 137 138 def create_capture(source = 0, fallback = presets['chess']): 139 '''source: <int> or '<int>|<filename>|synth [:<param_name>=<value> [:...]]' 140 ''' 141 source = str(source).strip() 142 chunks = source.split(':') 143 # handle drive letter ('c:', ...) 144 if len(chunks) > 1 and len(chunks[0]) == 1 and chunks[0].isalpha(): 145 chunks[1] = chunks[0] + ':' + chunks[1] 146 del chunks[0] 147 148 source = chunks[0] 149 try: source = int(source) 150 except ValueError: pass 151 params = dict( s.split('=') for s in chunks[1:] ) 152 153 cap = None 154 if source == 'synth': 155 Class = classes.get(params.get('class', None), VideoSynthBase) 156 try: cap = Class(**params) 157 except: pass 158 else: 159 cap = cv2.VideoCapture(source) 160 if 'size' in params: 161 w, h = map(int, params['size'].split('x')) 162 cap.set(cv2.CAP_PROP_FRAME_WIDTH, w) 163 cap.set(cv2.CAP_PROP_FRAME_HEIGHT, h) 164 if cap is None or not cap.isOpened(): 165 print 'Warning: unable to open video source: ', source 166 if fallback is not None: 167 return create_capture(fallback, None) 168 return cap 169 170 if __name__ == '__main__': 171 import sys 172 import getopt 173 174 print __doc__ 175 176 args, sources = getopt.getopt(sys.argv[1:], '', 'shotdir=') 177 args = dict(args) 178 shotdir = args.get('--shotdir', '.') 179 if len(sources) == 0: 180 sources = [ 0 ] 181 182 caps = map(create_capture, sources) 183 shot_idx = 0 184 while True: 185 imgs = [] 186 for i, cap in enumerate(caps): 187 ret, img = cap.read() 188 imgs.append(img) 189 cv2.imshow('capture %d' % i, img) 190 ch = 0xFF & cv2.waitKey(1) 191 if ch == 27: 192 break 193 if ch == ord(' '): 194 for i, img in enumerate(imgs): 195 fn = '%s/shot_%d_%03d.bmp' % (shotdir, i, shot_idx) 196 cv2.imwrite(fn, img) 197 print fn, 'saved' 198 shot_idx += 1 199 cv2.destroyAllWindows() 200
