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Tetragramm
GitHub Repository: Tetragramm/opencv
 Path: blob/master/samples/python/feature_homography.py
16337 views
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#!/usr/bin/env python

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'''

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Feature homography

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==================

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Example of using features2d framework for interactive video homography matching.

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ORB features and FLANN matcher are used. The actual tracking is implemented by

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PlaneTracker class in plane_tracker.py

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Inspired by http://www.youtube.com/watch?v=-ZNYoL8rzPY

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video: http://www.youtube.com/watch?v=FirtmYcC0Vc

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Usage

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-----

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feature_homography.py [<video source>]

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Keys:

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   SPACE  -  pause video

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Select a textured planar object to track by drawing a box with a mouse.

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'''

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# Python 2/3 compatibility

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from __future__ import print_function

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import numpy as np

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import cv2 as cv

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# local modules

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import video

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from video import presets

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import common

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from common import getsize, draw_keypoints

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from plane_tracker import PlaneTracker

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class App:

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    def __init__(self, src):

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        self.cap = video.create_capture(src, presets['book'])

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        self.frame = None

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        self.paused = False

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        self.tracker = PlaneTracker()

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        cv.namedWindow('plane')

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        self.rect_sel = common.RectSelector('plane', self.on_rect)

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    def on_rect(self, rect):

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        self.tracker.clear()

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        self.tracker.add_target(self.frame, rect)

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    def run(self):

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        while True:

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            playing = not self.paused and not self.rect_sel.dragging

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            if playing or self.frame is None:

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                ret, frame = self.cap.read()

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                if not ret:

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                    break

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                self.frame = frame.copy()

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            w, h = getsize(self.frame)

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            vis = np.zeros((h, w*2, 3), np.uint8)

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            vis[:h,:w] = self.frame

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            if len(self.tracker.targets) > 0:

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                target = self.tracker.targets[0]

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                vis[:,w:] = target.image

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                draw_keypoints(vis[:,w:], target.keypoints)

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                x0, y0, x1, y1 = target.rect

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                cv.rectangle(vis, (x0+w, y0), (x1+w, y1), (0, 255, 0), 2)

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            if playing:

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                tracked = self.tracker.track(self.frame)

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                if len(tracked) > 0:

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                    tracked = tracked[0]

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                    cv.polylines(vis, [np.int32(tracked.quad)], True, (255, 255, 255), 2)

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                    for (x0, y0), (x1, y1) in zip(np.int32(tracked.p0), np.int32(tracked.p1)):

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                        cv.line(vis, (x0+w, y0), (x1, y1), (0, 255, 0))

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            draw_keypoints(vis, self.tracker.frame_points)

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            self.rect_sel.draw(vis)

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            cv.imshow('plane', vis)

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            ch = cv.waitKey(1)

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            if ch == ord(' '):

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                self.paused = not self.paused

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            if ch == 27:

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                break

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if __name__ == '__main__':

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    print(__doc__)

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    import sys

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    try:

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        video_src = sys.argv[1]

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    except:

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        video_src = 0

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    App(video_src).run()

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