python-opencv 网络摄像头 ["noneType"]
几周前，我尝试用Python和OpenCV来移动鼠标指针……但当时没时间搞定。今天我偶然发现了一段可以做到这一点的代码，但我的问题是，现在用OpenCV打开摄像头不行了……
我在用Ubuntu 10.04……/dev/video0是可以工作的，我可以用命令luvсview -d /dev/video0来查看。
但是当我写camera = highgui.cvCreateCaptureCamera(0)并尝试输入(camera)时，结果是noneType……
我已经用apt-get remove --purge python-opencv把它卸载了，然后重新安装……但还是没法让它工作……我不知道哪里出问题了，几周前是可以的，现在却不行了……
这是用Python、OpenCV和Xlib控制鼠标的代码……
#! /usr/bin/env python
print "OpenCV Python version of lkdemo"
import sys
import os
sys.path.insert(1, os.path.join(sys.path[0], '..'))
from Xlib import X, display, Xutil
# 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 mouse callback
# the callback on the trackbar
class Window:
def __init__(self, display):
self.d = display
self.objects = []
# Find which screen to open the window on
self.screen = self.d.screen()
self.window = self.screen.root.create_window(
50, 50, 300, 200, 2,
self.screen.root_depth,
X.InputOutput,
X.CopyFromParent,
# special attribute values
background_pixel = self.screen.white_pixel,
event_mask = (X.ExposureMask |
X.StructureNotifyMask |
X.ButtonPressMask |
X.ButtonReleaseMask |
X.Button1MotionMask),
colormap = X.CopyFromParent,
)
self.gc = self.window.create_gc(
foreground = self.screen.black_pixel,
background = self.screen.white_pixel,
)
def mousekiller(self):
self.gc = self.window.warp_pointer (the_point.x*6, the_point.y*6, src_window = 0, src_x = 0, src_y = 0, src_width = 0, src_height = 0, onerror = None )
# Set some WM info
self.WM_DELETE_WINDOW = self.d.intern_atom('WM_DELETE_WINDOW')
self.WM_PROTOCOLS = self.d.intern_atom('WM_PROTOCOLS')
self.window.set_wm_name('Xlib example: draw.py')
self.window.set_wm_icon_name('draw.py')
self.window.set_wm_class('draw', 'XlibExample')
self.window.set_wm_protocols([self.WM_DELETE_WINDOW])
self.window.set_wm_hints(flags = Xutil.StateHint,
initial_state = Xutil.NormalState)
self.window.set_wm_normal_hints(flags = (Xutil.PPosition | Xutil.PSize
| Xutil.PMinSize),
min_width = 20,
min_height = 20)
# Map the window, making it visible
self.window.map()
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:
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__':
Window(display.Display())
capture = highgui.cvCreateCameraCapture(-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)
image.origin = frame.origin
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)
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
eig = cv.cvCreateImage (cv.cvGetSize (grey), 32, 1)
temp = cv.cvCreateImage (cv.cvGetSize (grey), 32, 1)
# the default parameters
quality = 0.01
min_distance = 10
# 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))
# release the temporary images
cv.cvReleaseImage (eig)
cv.cvReleaseImage (temp)
elif len (points [0]) > 0:
# we have points, so display them
# calculate the optical flow
points [1], status = cv.cvCalcOpticalFlowPyrLK (
prev_grey, grey, prev_pyramid, pyramid,
points [0], len (points [0]),
cv.cvSize (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,
[the_point.x, the_point.y],
3, cv.cvScalar (0, 255, 0, 0),
-1, 8, 0)
Window(display.Display()).mousekiller()
# 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
我不知道该怎么办了……希望有人遇到过这个问题并解决了……提前谢谢大家。
1 个回答
0
如果我理解得没错，你是想让鼠标反馈功能正常工作。
为了实现这个功能，你需要创建一个“响应者”函数（下面文档中的“OnMouse”函数）。这个函数会被cv2.setMouseCallBack函数使用。
举个例子：
def mouseHandle(event, x, y, flag, param):
if (flag == 1):
print "hoosier at" + str(x) + " , " + str(y);
你还需要在代码中定义一些标志值，比如：
CV_EVENT_LBUTTONDOWN = 1;
现在在你的主函数中：
im = cv2.imread('myimage.jpg')
cv2.imshow('image', im)
cv2.setMouseCallback('image', mouseHandle, CV_EVENT_LBUTTONDOWN)
作为参考，这里是来自opencv文档的函数信息： http://opencv.willowgarage.com/documentation/python/highgui_user_interface.html
SetMouseCallback(windowName, onMouse, param) → None 为鼠标事件分配回调函数。
参数： windowName (str) – 窗口的名称。
onMouse (PyCallableObject) – 每当在指定窗口中发生鼠标事件时调用的函数。这个函数的格式应该是 Foo(event, x, y, flags, param)-> None，其中event是CV_EVENT_*中的一个，x和y是鼠标指针在图像坐标中的位置（而不是窗口坐标），flags是CV_EVENT_FLAG_*的组合，param是传递给cvSetMouseCallback函数的用户自定义参数。
param (object) – 传递给回调函数的用户自定义参数。 函数cvSetMouseCallback设置了在指定窗口内发生的鼠标事件的回调函数。