I'm trying to get the background image from BackgroundSubtractorMOG2:
bg->getBackgroundImage(back);
but I get a Thread 1 SIGABRT (which as a c++ n00b puzzles me)
and this error:
OpenCV Error: Assertion failed (nchannels == 3) in getBackgroundImage, file /Users/hm/Downloads/OpenCV-2.4.4/modules/video/src/bgfg_gaussmix2.cpp, line 579
libc++abi.dylib: terminate called throwing an exception
(lldb)
I'm not sure what the problem is, suspecting it's something to do with the nmixtures paramater, but I've left that as the default(3). Any hints ?
It looks like you need to use 3 channel images rather than grayscale. Make sure the image type you are using is CV_8UC3 or if you are reading from a file use cv::imread('path/to/file') with no additional arguments.
Related
I am trying to display a basic image that is loaded off disk using the highgui module within the cv2 library.
I am able to do this when making a Qt Widgets application but the Qt window becomes redundant; however when using a console application I obtain this error:
OpenCV Error: Assertion failed (size.width>0 && size.height>0) in imshow, file /build/opencv-ISmtkH/opencv-2.4.9.1+dfsg/modules/highgui/src/window.cpp, line 269
terminate called after throwing an instance of 'cv::Exception'
what(): /build/opencv-ISmtkH/opencv-2.4.9.1+dfsg/modules/highgui/src/window.cpp:269: error: (-215) size.width>0 && size.height>0 in function imshow
Here is my code:
int main ()
{
cv::Mat inputImg = cv::imread("/home/pi/scrot1.png");
cv::imshow("Display Image", inputImg);
}
I have written a script in python that can be run via terminal and it calls the high gui module. I would like to write this in C++ but I cannot seem to be able to load a basic image!
EDIT:
The path was actually invalid. However, even with the correct path I cannot see the image with HighGui.
The error means that the image is not loaded correctly.
You can check this using:
if(image.empty()) {
// not loaded correctly
}
You need to be sure that:
the path is valid
the image is not corrupted
you have the privileges to access that folder
To actually display the image, you need to use cv::waitKey() after the imshow.
I'm writing a pattern matching code using OpenCV with CUDA on Mac OS X. After ~ 70 frames, it slows down a lot. Using mach_absolute_time() I've been able to track the culprit (Initially I thought it was a disk access issue):
gpu::matchTemplate(currentFrame,
correlationTargets[i]->correlationImage,
temporaryImage,
CV_TM_CCOEFF_NORMED);
I believe this is caused by some memory issue inside matchTemplate. After a lot of search, I found the matchTemplateBuf structure which is presumably for memory reuse. Since the problem seems memory releated, I think using this may be the solution. However, the following code crashes:
gpu::MatchTemplateBuf mtBuff;
[...]
for(...) {
gpu::matchTemplate(correlationTargets[i]->croppedImage,
correlationTargets[i]->correlationImage,
correlationTargets[i]->maxAllocation,
CV_TM_CCOEFF_NORMED, mtBuff);
With error:
OpenCV Error: Gpu API call (Unknown error code [Code = 9999]) in convolve, file /Users/sermarc/Downloads/opencv-2.4-3.8/modules/gpu/src/imgproc.cpp, line 1431 libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /Users/sermarc/Downloads/opencv-2.4-3.8/modules/gpu/src/imgproc.cpp:1431: error: (-217) Unknown error code [Code = 9999] in function convolve
I believe this is because the matchTemplateBuff is not properly initialized. However, I cannot find any information or example that shows it being set on a valid state.
The code works with:
gpu::matchTemplate(correlationTargets[i]->croppedImage,
correlationTargets[i]->correlationImage,
correlationTargets[i]->maxAllocation,
CV_TM_CCOEFF_NORMED);
I'm trying to get the output of gphoto2 movie capture over to my opencv program over a pipe
gphoto2 --capture-movie --stdin | ./myexe
My first attempt was to do it like this:
while(1)
{
std::stringstream ss;
ss << "/dev/stdin";
cv::Mat m = cv::imread(ss.str());
namedWindow( "LiveView", WINDOW_AUTOSIZE );
imshow( "LiveView", m );
waitKey(1);
}
But sadly, while compiling works, executing doesn't, I am getting an
OpenCV Error: Bad flag (parameter or structure field) (Unrecognized or unsupported array type) in cvGetMat, file /build/buildd/opencv-2.4.2+dfsg/modules/core/src/array.cpp, line 2482 terminate called after throwing an instance of 'cv::Exception'
what(): /build/buildd/opencv-2.4.2+dfsg/modules/core/src/array.cpp:2482: error: (-206) Unrecognized or unsupported array type in function cvGetMat
I saw something similar asked here, but it doesn't work for me - compiling fails at
readbytes=read(fileno(stdin),ca,BUFSIZE);
error: no matching function for call to ‘read(int, char [10240], int)’
I'm quite a novice to c++/opencv, so I'm probably missing some includes or something.
Because I'm a new user, I cannot comment to ask for help/clarification over there, so I decided to ask a new question instead.
This piping seems to be bad coding practice. Use the libgphoto API to extract the images/movie and use that with your OpenCV stuff.
It's easier than it sounds. See this blogpost: http://sepharads.blogspot.nl/2011/11/camera-tethered-capturing-using.html
My MFC app runs various API from OpenCV2. Everything else is working fine. But when my program runs
cv::Mat result;
cv::equalizeHist(m_cvImage,result);
I get following runtime exception.
Unhandled exception at 0x7727fbae in OpenCVTest.exe: Microsoft C++ exception: cv::Exception at memory location 0x0029e944..
"C:\slave\WinInstallerMegaPack\src\opencv\modules\imgproc\src\histogram.cpp:2430: error: (-215) CV_ARE_SIZES_EQ(src, dst) && CV_ARE_TYPES_EQ(src, dst) && CV_MAT_TYPE(src->type) == CV_8UC1"
According to debugger, the exception was thrown in the middle of processing (about 40%) the image in equalizeHist. Is there anything I need to do? FYI: I am using binary OpenCV provided by its web site.
UPDATE:
I've resolved this issue by converting images to gray-level before equalizing it. I just didn't know
the function only works with gray-level image
images that look like gray-level can be non-gray.
I imagine the problem you are encountering is that m_cvImage is a 3-channel image. So, you need to convert it to a grayscale image before you can call equalizeHist.
cvtColor(m_cvImage, m_cvImage, CV_BGR2GRAY);
cv::Mat result;
cv::equalizeHist(m_cvImage, result);
Also, have a look at the EqualizeHist_Demo.cpp tutorial sample to see how it is used.
I have successfully written a video processing program. I used ubuntu and Netbeans for programming. When I run this program on netbeans it runs perfectly and gives expected output.
I built executable file of this program both in debug and release mode and tried to run them in the command line. Now I get the following error. But Netbeans doesn't complain about this. Could someone point out what might be the problem?
OpenCV Error: Bad argument (Array should be CvMat or IplImage) in cvGetSize, file /home/<user>/trunk/opencv/modules/core/src/array.cpp, line 1238
terminate called after throwing an instance of 'cv::Exception'
what(): /home/<user>/trunk/opencv/modules/core/src/array.cpp:1238: error: (-5) Array should be CvMat or IplImage in function cvGetSize
thank you in advance
Can you check if the input argument to cvGetSize is:
a NULL pointer? What is the result of querying/retrieving the frame?
a CvSeq?
a 1- or 3-dimensional array?
Usually it is the first.
That's the way OpenCV talks to you - it's more often the runtime exception than a compiler error.