I'm working on an Udoo trying to get the camera to take a picture that I can manipulate inside Python.
So far, the camera works with
gst-launch-1.0 imxv4l2videosrc ! imxipuvideosink
I can also take a single picture with
gst-launch-1.0 imxv4l2videosrc num-buffers=1 ! video/x-raw ! jpegenc ! filesink location=output.jpg
From here it seems like you can read straight from a gstreamer stream in Python with OpenCV.
Here is my python code:
import cv2
cam = cv2.VideoCapture("imxv4l2videosrc ! video/x-raw ! appsink")
ret, image = cam.read()
However, ret is False, and image is nothing.
Some places say this only works with OpenCV 3.0+, and others say 2.4.x, but I can't seem to find an actual answer to what version it works on.
If I need to update to OpenCV 3.0, which part to I update? I downloaded OpenCV via the apt repositories under the package python-opencv. So do I need to update Python? Can I just build OpenCV from source, and Python will automatically be using the newest version? I'm so confused.
The Ubuntu/Debian version is old 2.4.x, to get the last one you need to compile it from source.
Here two tutorials on how to do that:
https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_setup/py_setup_in_fedora/py_setup_in_fedora.html#installing-opencv-from-source
http://www.pyimagesearch.com/2015/07/20/install-opencv-3-0-and-python-3-4-on-ubuntu/
The first is for Python 2.7 on Fedora, the second for Python 3.4 on Ubuntu.
Related
I am trying to detect Aruco markers through my camera using OpenCV for Python 2.7 on Debian 9.5, but I can't run my code because of an errore dealing with cv2.aruco.detectMarkers(). Running it on Windows, it does not have any problem. In particular, I wrote in my code:
cv2.aruco.detectMarkers(image=gray, dictionary=aruco_dict, parameters=parameters,
cameraMatrix=camera_matrix, distCoeff=camera_distortion)
where camera_matrix and camera_distortion are respectively the camera matrix and the camera distortion parameters I got by camera calibration.
More precisely, the error says that there's no cameraMatrix input parameter for the function cv2.aruco.detectMarkers. How do I fix this problem? Thank you very much in advance.
Maybe your error is due to your opencv version. Check it with:
cv2.__version__
Older versions of opencv (such as 3.2.0, that is maybe your default version for Debian 9) do not have cameraMatrix or distCoeff as input parameters of cv2.aruco.detectMarkers function.
If you are interested in getting newer versions of opencv for your OS (such as 4.1.0.25), you have to do:
sudo pip install opencv-contrib-python==4.1.0.25
If you are not, just remove cameraMatrix and distCoeff from your inputs, it would run anyway.
I installed OpenCV3.2 + python3.6.1 from this installation guide. (For the paths needed in guide I typed:
Edit: I'm not sure, but I guess that I should install opencv under 3.6, not 3.6.1, please don't use my paths for your installation!
/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib
and
ls -d /usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/include/python3.6m/)
My testing code is completely the same as the tutorial of OpenCV 3.2 documentation, but the output screen show nothing but a title:
import numpy as np
import cv2
img = cv2.imread('1.jpg',0)
cv2.imshow('image', img)
cv2.waitKey(0)
The result:
As the picture shown the content of the image is missing.
and it seems that it has something to do with my python, the icon is broken:
Please help me! I just want to use opencv for my school project...
If you just encounter the same problem, I can solve your problem. But you should take a look before you follow any further steps:
I will recommend you first delete OpenCV 3.2 from your mac.
Don't know how to delele? Here are the steps:
Read this answer first if you want to know what the following command do in details, then run the following command in your Terminal:
$> sudo find / -name "*opencv*" -exec rm -i {} \;
Please read every delete-checking message carefully, or you may delete some of your files containing "opencv" in filename, which may not related to OpenCV but may be your personal files.
Your cv2.so will still alive somewhere in your disk, go checkout where it is with the following command in Terminal:
$> ls -l /usr/local/lib/python3.6/site-packages/
In my case I found the cv2.so at .../python3.6/..., you should press 'tab' at /usr/local/lib/python then check out the site-packages folder for each python version (,which maybe you're about to re-install the OpenCV,) to search cv2.so. if you found it, delete it.
Install OpenCV3.2 with Homebrew for Python2.7 / 3.6. Just follow all the steps, and keep in mind that Homebrew is your best friend.
Edit: The link works for both Python2.7 and 3.6.
I ran into a similar issue but on the C++ API perspective. Credits go out to mattmyne.
Window autosize was not working for macOS using cocoa. The window's image dimensions could not be found. This has been fixed by removing IP64 specific synthesize in window_cocoa.mm that was causing null reference for the window's contentView image property in cvShowImage (image reference was not linked to _image).
In a nutshell, OpenCV tried to support both 32 and 64-bit ObjC compilers but since Apple no longer supports 32-bit, some image synthesizing operations resulted in null references in 64-bit machines. More info
To resolve this, locate the file window_cocoa.mm; if built from source it'll be in opencv/modules/highgui/src.
Change this
#implementation CVView
#if defined(__LP64__)
#synthesize image;
#else // 32-bit Obj-C does not have automatic synthesize
#synthesize image = _image;
#endif
To this
#implementation CVView
#synthesize image = _image;
Do the same thing for the CVWindow and CVSlider implementations to accommodate videos as well.
Recompile OpenCV and test out your code.
I am trying to write an OCR program in python. Now i got a program which perform OCR on digits and uses KNearest() function in cv2. But i didn't find any KNearest() function in cv2 while compiling the same. I already installed OpenCV form prebuilt binary cv2.pyd ( as per instructions given by site http://docs.opencv.org/trunk/doc/py_tutorials/py_setup/py_setup_in_windows/py_setup_in_windows.html#install-opencv-python-in-windows).
I'm assuming you are using OpenCV 3.x rather than 2.x. If this is the case, you'll want to replace
model = cv2.KNearest()
with
model = cv2.ml.KNearest_create()
>>> import cv2
>>> print cv2.KNearest
<built-in function KNearest>
If you're not able to do this, you most likely have a bad or old installation of opencv or its python bindings.
You didn't specify your OS, but if you're using any modern debian based distro (ubuntu, mint, ...), apt-get install python-opencv should suffice.
I am very new to raspberry pi and python.
I am trying write a progam using python on raspberry pi to use the Kinect. I aim to install OpenKinect on Raspberry pi.
So far I have done:
apt-cache search OpenKinect
sudo apt-get install python-freenect
sudo apt-get update
Next i tried writing a code in python from this link https://github.com/OpenKinect/libfreenect/blob/master/wrappers/python/demo_cv_async.py
When i try to run the programe, it says that
error in line 5,
import cv.
ImportError:no module named cv.
I am not sure if i have installed all the necessary files. I am also not sure what i have done wrong.
I also have been trying to look for tutorials on installing and using OpenKinect.
Congradtulations on starting python! That sounds like a complicated project to start on. You should probably try doing the tutorial first at python.org. I particularily like the google video tutorials (if you are a classroom kind of person): http://www.youtube.com/watch?v=tKTZoB2Vjuk
After that you can dig into more detailed stuff :)
It looks like you still dont have opencv package for python. Try to install it:
sudo apt-get install python-opencv
The OpenGL or GTK-Warning: Cannot open display. Or the other one you stated
Number of deviced found:1 GL thread write reg 0x0105 <= 0x00 freeglut(freenect-glview):
OpenGL GLX extension not supported by display ':o.o'
is because freenect does not support OpenGL. It probably uses EGL.
bmwesting (Brandt) wrote:
"The freenect library provides a demo for the Kinect called glview. The glview program will > not work with the Pi because the program is written using OpenGL. The Raspberry Pi only supports GLES through EGL.
It seems like you will be able to use libfreenect to grab the depth stream and rgb stream, > but will be unable to run the demo program because it uses the incorrect graphics API."
If you read through that thread, it should show the alternatives (i.e. ASUS XTion instead of Kinect). They reach 30fps at high (~ 1024x800) resolution for depth data if using console output mode. I plan to go for Xtion now too - and I hope to get deactivate as much as possible from the USB bus (as this seems to be the bottleneck, for the Kinect too I think).
When you install OpenCV using apt-get install python-opencv you are installing version 2. However, you can still use the methods from version 1 by doing so:
import cv2.cv as cv
I'm trying to write a simple python script to capture an image from a webcam using OpenCV. This is running on Ubuntu 11.10 32-bit.
when I run lsusb in the terminal i get:
Bus 002 Device 002: ID 045e:00f7 Microsoft Corp. LifeCam VX-1000
Which leads me to believe that the driver for the camera is installed
In a python shell I type:
capture=cv.CaptureFromCAM(0) # also tried -1, 1, 2, 3
but capture is always null.
I also tried:
capture = cv.CreateCameraCapture(0)
But i get the same results.
Would appreciate any help
Cheers,
Merely probing the driver does not validate that the camera will work.
Here is a ubuntu support page on testing your camera with vlc
Basically you should try something like :
$ vlc v4l2:///dev/video0
I don't think this camera is supported by OpenCV.
OpenCV has a compatibility list, check if yours is there.