1#!/usr/bin/env python
2
3'''
4Camshift tracker
5================
6
7This is a demo that shows mean-shift based tracking
8You select a color objects such as your face and it tracks it.
9This reads from video camera (0 by default, or the camera number the user enters)
10
11http://www.robinhewitt.com/research/track/camshift.html
12
13Usage:
14------
15    camshift.py [<video source>]
16
17    To initialize tracking, select the object with mouse
18
19Keys:
20-----
21    ESC   - exit
22    b     - toggle back-projected probability visualization
23'''
24
25import numpy as np
26import cv2
27
28# local module
29import video
30
31
32class App(object):
33    def __init__(self, video_src):
34        self.cam = video.create_capture(video_src)
35        ret, self.frame = self.cam.read()
36        cv2.namedWindow('camshift')
37        cv2.setMouseCallback('camshift', self.onmouse)
38
39        self.selection = None
40        self.drag_start = None
41        self.tracking_state = 0
42        self.show_backproj = False
43
44    def onmouse(self, event, x, y, flags, param):
45        x, y = np.int16([x, y]) # BUG
46        if event == cv2.EVENT_LBUTTONDOWN:
47            self.drag_start = (x, y)
48            self.tracking_state = 0
49        if self.drag_start:
50            if flags & cv2.EVENT_FLAG_LBUTTON:
51                h, w = self.frame.shape[:2]
52                xo, yo = self.drag_start
53                x0, y0 = np.maximum(0, np.minimum([xo, yo], [x, y]))
54                x1, y1 = np.minimum([w, h], np.maximum([xo, yo], [x, y]))
55                self.selection = None
56                if x1-x0 > 0 and y1-y0 > 0:
57                    self.selection = (x0, y0, x1, y1)
58            else:
59                self.drag_start = None
60                if self.selection is not None:
61                    self.tracking_state = 1
62
63    def show_hist(self):
64        bin_count = self.hist.shape[0]
65        bin_w = 24
66        img = np.zeros((256, bin_count*bin_w, 3), np.uint8)
67        for i in xrange(bin_count):
68            h = int(self.hist[i])
69            cv2.rectangle(img, (i*bin_w+2, 255), ((i+1)*bin_w-2, 255-h), (int(180.0*i/bin_count), 255, 255), -1)
70        img = cv2.cvtColor(img, cv2.COLOR_HSV2BGR)
71        cv2.imshow('hist', img)
72
73    def run(self):
74        while True:
75            ret, self.frame = self.cam.read()
76            vis = self.frame.copy()
77            hsv = cv2.cvtColor(self.frame, cv2.COLOR_BGR2HSV)
78            mask = cv2.inRange(hsv, np.array((0., 60., 32.)), np.array((180., 255., 255.)))
79
80            if self.selection:
81                x0, y0, x1, y1 = self.selection
82                self.track_window = (x0, y0, x1-x0, y1-y0)
83                hsv_roi = hsv[y0:y1, x0:x1]
84                mask_roi = mask[y0:y1, x0:x1]
85                hist = cv2.calcHist( [hsv_roi], [0], mask_roi, [16], [0, 180] )
86                cv2.normalize(hist, hist, 0, 255, cv2.NORM_MINMAX);
87                self.hist = hist.reshape(-1)
88                self.show_hist()
89
90                vis_roi = vis[y0:y1, x0:x1]
91                cv2.bitwise_not(vis_roi, vis_roi)
92                vis[mask == 0] = 0
93
94            if self.tracking_state == 1:
95                self.selection = None
96                prob = cv2.calcBackProject([hsv], [0], self.hist, [0, 180], 1)
97                prob &= mask
98                term_crit = ( cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 1 )
99                track_box, self.track_window = cv2.CamShift(prob, self.track_window, term_crit)
100
101                if self.show_backproj:
102                    vis[:] = prob[...,np.newaxis]
103                try:
104                    cv2.ellipse(vis, track_box, (0, 0, 255), 2)
105                except:
106                    print track_box
107
108            cv2.imshow('camshift', vis)
109
110            ch = 0xFF & cv2.waitKey(5)
111            if ch == 27:
112                break
113            if ch == ord('b'):
114                self.show_backproj = not self.show_backproj
115        cv2.destroyAllWindows()
116
117
118if __name__ == '__main__':
119    import sys
120    try:
121        video_src = sys.argv[1]
122    except:
123        video_src = 0
124    print __doc__
125    App(video_src).run()
126