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|
#! /usr/bin/env python
print "OpenCV Python version of lkdemo"
import sys
# import the necessary things for OpenCV
from opencv import cv
from opencv import highgui
#############################################################################
# some "constants"
win_size = 10
MAX_COUNT = 500
#############################################################################
# some "global" variables
image = None
pt = None
add_remove_pt = False
flags = 0
night_mode = False
need_to_init = False
# the default parameters
quality = 0.01
min_distance = 10
#############################################################################
# the mouse callback
# the callback on the trackbar
def on_mouse (event, x, y, flags, param):
# we will use the global pt and add_remove_pt
global pt
global add_remove_pt
if image is None:
# not initialized, so skip
return
if event == highgui.CV_EVENT_LBUTTONDOWN:
# user has click, so memorize it
pt = cv.cvPoint (x, y)
add_remove_pt = True
#############################################################################
# so, here is the main part of the program
if __name__ == '__main__':
try:
# try to get the device number from the command line
device = int (sys.argv [1])
# got it ! so remove it from the arguments
del sys.argv [1]
except (IndexError, ValueError):
# no device number on the command line, assume we want the 1st device
device = 0
if len (sys.argv) == 1:
# no argument on the command line, try to use the camera
capture = highgui.cvCreateCameraCapture (device)
else:
# we have an argument on the command line,
# we can assume this is a file name, so open it
capture = highgui.cvCreateFileCapture (sys.argv [1])
# check that capture device is OK
if not capture:
print "Error opening capture device"
sys.exit (1)
# display a small howto use it
print "Hot keys: \n" \
"\tESC - quit the program\n" \
"\tr - auto-initialize tracking\n" \
"\tc - delete all the points\n" \
"\tn - switch the \"night\" mode on/off\n" \
"To add/remove a feature point click it\n"
# first, create the necessary windows
highgui.cvNamedWindow ('LkDemo', highgui.CV_WINDOW_AUTOSIZE)
# register the mouse callback
highgui.cvSetMouseCallback ('LkDemo', on_mouse, None)
while 1:
# do forever
# 1. capture the current image
frame = highgui.cvQueryFrame (capture)
if frame is None:
# no image captured... end the processing
break
if image is None:
# create the images we need
image = cv.cvCreateImage (cv.cvGetSize (frame), 8, 3)
grey = cv.cvCreateImage (cv.cvGetSize (frame), 8, 1)
prev_grey = cv.cvCreateImage (cv.cvGetSize (frame), 8, 1)
pyramid = cv.cvCreateImage (cv.cvGetSize (frame), 8, 1)
prev_pyramid = cv.cvCreateImage (cv.cvGetSize (frame), 8, 1)
eig = cv.cvCreateImage (cv.cvGetSize (frame), cv.IPL_DEPTH_32F, 1)
temp = cv.cvCreateImage (cv.cvGetSize (frame), cv.IPL_DEPTH_32F, 1)
points = [[], []]
# copy the frame, so we can draw on it
cv.cvCopy (frame, image)
# create a grey version of the image
cv.cvCvtColor (image, grey, cv.CV_BGR2GRAY)
if night_mode:
# night mode: only display the points
cv.cvSetZero (image)
if need_to_init:
# we want to search all the good points
# create the wanted images
# search the good points
points [1] = cv.cvGoodFeaturesToTrack (
grey, eig, temp,
MAX_COUNT,
quality, min_distance, None, 3, 0, 0.04)
# refine the corner locations
cv.cvFindCornerSubPix (
grey,
points [1],
cv.cvSize (win_size, win_size), cv.cvSize (-1, -1),
cv.cvTermCriteria (cv.CV_TERMCRIT_ITER | cv.CV_TERMCRIT_EPS,
20, 0.03))
elif len (points [0]) > 0:
# we have points, so display them
# calculate the optical flow
[points [1], status], something = cv.cvCalcOpticalFlowPyrLK (
prev_grey, grey, prev_pyramid, pyramid,
points [0], len (points [0]),
(win_size, win_size), 3,
len (points [0]),
None,
cv.cvTermCriteria (cv.CV_TERMCRIT_ITER|cv.CV_TERMCRIT_EPS,
20, 0.03),
flags)
# initializations
point_counter = -1
new_points = []
for the_point in points [1]:
# go trough all the points
# increment the counter
point_counter += 1
if add_remove_pt:
# we have a point to add, so see if it is close to
# another one. If yes, don't use it
dx = pt.x - the_point.x
dy = pt.y - the_point.y
if dx * dx + dy * dy <= 25:
# too close
add_remove_pt = 0
continue
if not status [point_counter]:
# we will disable this point
continue
# this point is a correct point
new_points.append (the_point)
# draw the current point
cv.cvCircle (image,
cv.cvPointFrom32f(the_point),
3, cv.cvScalar (0, 255, 0, 0),
-1, 8, 0)
# set back the points we keep
points [1] = new_points
if add_remove_pt:
# we want to add a point
points [1].append (cv.cvPointTo32f (pt))
# refine the corner locations
points [1][-1] = cv.cvFindCornerSubPix (
grey,
[points [1][-1]],
cv.cvSize (win_size, win_size), cv.cvSize (-1, -1),
cv.cvTermCriteria (cv.CV_TERMCRIT_ITER | cv.CV_TERMCRIT_EPS,
20, 0.03))[0]
# we are no more in "add_remove_pt" mode
add_remove_pt = False
# swapping
prev_grey, grey = grey, prev_grey
prev_pyramid, pyramid = pyramid, prev_pyramid
points [0], points [1] = points [1], points [0]
need_to_init = False
# we can now display the image
highgui.cvShowImage ('LkDemo', image)
# handle events
c = highgui.cvWaitKey (10)
if c == '\x1b':
# user has press the ESC key, so exit
break
# processing depending on the character
if c in ['r', 'R']:
need_to_init = True
elif c in ['c', 'C']:
points = [[], []]
elif c in ['n', 'N']:
night_mode = not night_mode
|
