Python 2.7上的OpenCV访问我的网络摄像头没有问题。由于某种原因，它不能在Python 3中.VideoCapture :: read总是返回无...
我甚至尝试过从源代码编译。
这是我的cmake（我认为我没有做错任何事）：
cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D INSTALL_C_EXAMPLES=OFF \
-D WITH_V4L=ON \
-D WITH_QT=ON \
-D WITH_OPENGL=ON \
-D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \
-D PYTHON_EXECUTABLE3=/usr/bin/python3.6
-D PYTHON_EXECUTABLE2=/usr/bin/python2.7
-D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/lib64/python3.6/site-packages/numpy/core/include \
-D BUILD_EXAMPLES=ON ..
实施之间是否有任何改变，可能表明我的问题是什么？
编辑：
根据要求：
% python3.6 -c 'import cv2; print(cv2.getBuildInformation())'
General configuration for OpenCV 3.3.0
=====================================
Version control: 3.3.0
Extra modules:
Location (extra): /io/opencv_contrib/modules
Version control (extra): 3.3.0
Platform:
Timestamp: 2017-09-03T11:00:53Z
Host: Linux 4.4.0-83-generic x86_64
CMake: 3.9.0
CMake generator: Unix Makefiles
CMake build tool: /usr/bin/gmake
Configuration: Release
CPU/HW features:
Baseline: SSE SSE2 SSE3
requested: SSE3
Dispatched code generation: SSE4_1 SSE4_2 FP16 AVX AVX2
requested: SSE4_1 SSE4_2 AVX FP16 AVX2
SSE4_1 (2 files): + SSSE3 SSE4_1
SSE4_2 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2
FP16 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
AVX (5 files): + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
AVX2 (7 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2
C/C++:
Built as dynamic libs?: NO
C++ Compiler: /opt/rh/devtoolset-2/root/usr/bin/c++ (ver 4.8.2)
C++ flags (Release): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG
C++ flags (Debug): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG
C Compiler: /opt/rh/devtoolset-2/root/usr/bin/cc
C flags (Release): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG -DNDEBUG
C flags (Debug): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUG
Linker flags (Release):
Linker flags (Debug):
ccache: NO
Precompiled headers: YES
Extra dependencies: /opt/Qt4.8.7/lib/libQtGui.so /opt/Qt4.8.7/lib/libQtTest.so /opt/Qt4.8.7/lib/libQtCore.so /lib64/libz.so stdc++ dl m pthread rt
3rdparty dependencies: ittnotify libprotobuf libjpeg libwebp libpng libtiff libjasper IlmImf
OpenCV modules:
To be built: core flann imgproc ml objdetect phase_unwrapping photo plot reg surface_matching video xphoto bgsegm dnn face fuzzy img_hash imgcodecs shape videoio xobjdetect highgui superres bioinspired dpm features2d line_descriptor saliency text calib3d ccalib datasets rgbd stereo structured_light tracking videostab xfeatures2d ximgproc aruco optflow stitching python3
Disabled: world contrib_world
Disabled by dependency: -
Unavailable: cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev java python2 ts viz cnn_3dobj cvv dnn_modern freetype hdf matlab sfm
GUI:
QT 4.x: YES (ver 4.8.7 EDITION = OpenSource)
QT OpenGL support: NO
OpenGL support: NO
VTK support: NO
Media I/O:
ZLib: /lib64/libz.so (ver 1.2.3)
JPEG: libjpeg (ver 90)
WEBP: build (ver encoder: 0x020e)
PNG: build (ver 1.6.24)
TIFF: build (ver 42 - 4.0.2)
JPEG 2000: build (ver 1.900.1)
OpenEXR: build (ver 1.7.1)
GDAL: NO
GDCM: NO
Video I/O:
DC1394 1.x: NO
DC1394 2.x: NO
FFMPEG: NO
avcodec: NO
avformat: NO
avutil: NO
swscale: NO
avresample: NO
GStreamer: NO
OpenNI: NO
OpenNI PrimeSensor Modules: NO
OpenNI2: NO
PvAPI: NO
GigEVisionSDK: NO
Aravis SDK: NO
UniCap: NO
UniCap ucil: NO
V4L/V4L2: NO/NO
XIMEA: NO
Xine: NO
Intel Media SDK: NO
gPhoto2: NO
Parallel framework: pthreads
Trace: YES (with Intel ITT)
Other third-party libraries:
Use Intel IPP: NO
Use Intel IPP IW: NO
Use Intel IPP Async: NO
Use VA: NO
Use Intel VA-API/OpenCL: NO
Use Lapack: NO
Use Eigen: NO
Use Cuda: NO
Use OpenCL: YES
Use OpenVX: NO
Use custom HAL: NO
OpenCL: <Dynamic loading of OpenCL library>
Include path: /io/opencv/3rdparty/include/opencl/1.2
Use AMDFFT: NO
Use AMDBLAS: NO
Python 2:
Interpreter: NO
Python 3:
Interpreter: python (ver 3.6.0)
Libraries:
numpy: /opt/python/cp36-cp36m/lib/python3.6/site-packages/numpy/core/include (ver 1.11.3)
packages path: /opt/python/cp36-cp36m/lib/python3.6/site-packages
Python (for build): python
Java:
ant: NO
JNI: NO
Java wrappers: NO
Java tests: NO
Matlab: Matlab not found or implicitly disabled
Tests and samples:
Tests: NO
Performance tests: NO
C/C++ Examples: NO
Install path: /usr/local
cvconfig.h is in: /io/opencv/build
-----------------------------------------------------------------
答案 0 :(得分：0)
遵循本指南：https://www.scivision.co/anaconda-python-opencv3/
在安装之前删除所有使用pip的失败尝试。
确保您在上面的指南中执行的命令使用您要定位的python版本。将python别名为python36或在命令中替换它。