use cv2 function

added color_histogram.py sample
work on VideoSynth (chessboard)

samples/python2/video.py

@@ -1,11 +1,10 @@
 import numpy as np
 import cv2
 from time import clock
+from numpy import pi, sin, cos
+import common
 
-def lookat(cam_pos, target_pos, up = ()):
-    dp = cam_pos - target_pos
-
-class VideoSynth(object):
+class VideoSynthBase(object):
     def __init__(self, size=None, noise=0.0, bg = None, **params):
         self.bg = None
         self.frame_size = (640, 480)
@@ -17,19 +16,13 @@ class VideoSynth(object):
         if size is not None:
             w, h = map(int, size.split('x'))
             self.frame_size = (w, h)
-            self.bg = cv2.resize(bg, self.frame_size)
+            self.bg = cv2.resize(self.bg, self.frame_size)
 
         self.noise = float(noise)
 
-        w, h = self.frame_size
-        self.K = np.float64([[1.0/w,   0.0, 0.5*(w-1)], 
-                             [  0.0, 1.0/w, 0.5*(h-1)],
-                             [  0.0,   0.0,       1.0]])
-
-    def draw_layers(self, dst):
+    def render(self, dst):
         pass
         
-
     def read(self, dst=None):
         w, h = self.frame_size
 
@@ -38,7 +31,7 @@ class VideoSynth(object):
         else:
             buf = self.bg.copy()
 
-        self.draw_layers(buf)
+        self.render(buf)
 
         if self.noise > 0.0:
             noise = np.zeros((h, w, 3), np.int8)
@@ -46,6 +39,54 @@ class VideoSynth(object):
             buf = cv2.add(buf, noise, dtype=cv2.CV_8UC3)
         return True, buf
 
+class Chess(VideoSynthBase):
+    def __init__(self, **kw):
+        super(Chess, self).__init__(**kw)
+
+        w, h = self.frame_size
+
+        self.grid_size = sx, sy = 10, 7
+        white_quads = []
+        black_quads = []
+        for i, j in np.ndindex(sy, sx):
+            q = [[j, i, 0], [j+1, i, 0], [j+1, i+1, 0], [j, i+1, 0]]
+            [white_quads, black_quads][(i + j) % 2].append(q)
+        self.white_quads = np.float32(white_quads)
+        self.black_quads = np.float32(black_quads)
+
+        fx = 0.9
+        self.K = np.float64([[fx*w, 0, 0.5*(w-1)],
+                        [0, fx*w, 0.5*(h-1)],
+                        [0.0,0.0,      1.0]])
+
+        self.dist_coef = np.float64([-0.2, 0.1, 0, 0])
+
+    def draw_quads(self, img, quads, color = (0, 255, 0)):
+        img_quads = cv2.projectPoints(quads.reshape(-1, 3), self.rvec, self.tvec, self.K, self.dist_coef) [0]
+        img_quads.shape = quads.shape[:2] + (2,) 
+        for q in img_quads:
+            cv2.fillConvexPoly(img, np.int32(q*4), color, cv2.CV_AA, shift=2)
+
+    def render(self, dst):
+        t = clock()
+        
+        sx, sy = self.grid_size
+        center = np.array([0.5*sx, 0.5*sy, 0.0])
+        phi = pi/3 + sin(t*3)*pi/8
+        c, s = cos(phi), sin(phi)
+        ofs = np.array([sin(1.2*t), cos(1.8*t), 0]) * sx * 0.2
+        eye_pos = center + np.array([cos(t)*c, sin(t)*c, s]) * 15.0 + ofs
+        target_pos = center + ofs
+
+        R, self.tvec = common.lookat(eye_pos, target_pos)
+        self.rvec = common.mtx2rvec(R)
+
+        self.draw_quads(dst, self.white_quads, (245, 245, 245))
+        self.draw_quads(dst, self.black_quads, (10, 10, 10))
+
+
+
+classes = dict(chess=Chess)
 
 def create_capture(source):
     '''
@@ -59,13 +100,17 @@ def create_capture(source):
     if source.startswith('synth'):
         ss = filter(None, source.split(':'))
         params = dict( s.split('=') for s in ss[1:] )
-        return VideoSynth(**params)
+        try: Class = classes[params['class']]
+        except: Class = VideoSynthBase
+
+        return Class(**params)
     return cv2.VideoCapture(source)
 
 
 presets = dict(
     empty = 'synth:',
-    lena = 'synth:bg=../cpp/lena.jpg:noise=0.1'
+    lena = 'synth:bg=../cpp/lena.jpg:noise=0.1',
+    chess = 'synth:class=chess:bg=../cpp/lena.jpg:noise=0.1:size=640x480'
 )
 
 if __name__ == '__main__':
@@ -80,7 +125,7 @@ if __name__ == '__main__':
     args = dict(args)
     shotdir = args.get('--shotdir', '.')
     if len(sources) == 0:
-        sources = [ presets['lena'] ]
+        sources = [ presets['chess'] ]
 
     print 'Press SPACE to save current frame'