A very simple question...why am I getting a read access violation error with this code?
cv::Mat laserSpeckle = Mat::zeros(100,100,CV_8UC1);
imwrite( "C://testimage.jpg", laserSpeckle );
When i attach a debugger and look into it further, it throws the exception at this snippet in grfmt.cpp.
if( params[i] == CV_IMWRITE_JPEG_QUALITY )
{
quality = params[i+1];
quality = MIN(MAX(quality, 0), 100);
}
It occurs with .png and .tiff too. Im an OpenCV newbie, my apologies if this is something really simple. I am using Qt for what its worth.
Do you build OpenCV yourself? If yes, make sure that the option WITH_JPEG is enabled when you configure your build files:
cmake ... -DWITH_JPEG=ON ...
If you want to save image with alpha channel you should use png format. It is described here
It should work with bmp format:
cv::Mat laserSpeckle = cv::Mat::zeros(100,100,CV_8UC1);
cv::imwrite( "C://testimage.bmp", laserSpeckle );
Your code also works on my computer. However, it seems that on some systems it works only for bmp images. I saw similar issues reported here and here.
The problem is with the debugger version (x64) if you build the code using the release version (x64) it works fine for me.
In my case c++ Code Generation settings were wrong
Should have been Multithreaded DEBUG dll MD
Related
Sorry, for an old question but I nothing found helful for me. I'm developing an iOS app using OpenCV 3.0 framework.
I'm using cvVideoCamera delgate to record video but as I set _cvVideoCam.recordVideo = YES;, it always gives me memory warning error.
If I set cvVideoCam,recordVideo = YES;, Then there is not any memory warning but also the output url always shows (null) at location, on recording finish.
Thanks in advance.
please check your
-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer.....
for -
withPresentationTime:lastSampleTime] )
{
NSLog(#"Video Writing Error");
}
if (pixelBuffer != nullptr)
CVPixelBufferRelease(pixelBuffer);
}
}
because, in some of earlier version OpenCV forgot to release memory upon each append operation to MPEG4 output. May be its your need.
I need to do the same thing of this video https://youtu.be/59RJeLlDAxQ but in Opencv. For now I'm doing this thing http://ramsrigoutham.com/2012/11/22/panorama-image-stitching-in-opencv/ with a little modify in the final image merging, but it doesn't work very well. How can I proceed?
EDIT
For testing I'm using the video lab from this page http://www.cs.ucsb.edu/~holl/CS290I/Assignments/Assignments-3/Assignment3Mosaicing.html
I ran my code on that video and I obtain this:
It's not very accurate but its ok.If I let the program run, at a certain point my stitcher produce this:
.
For the stitching ROIs instead of the ramsrigoutham.com ones I'm using this:
warpPerspective(current_frame, rImg, H, Size(current_frame.cols, current_frame.rows), INTER_NEAREST);
Mat roi1(final_img, Rect(img_loop.cols, img_loop.rows, vImg[1].cols, vImg[1].rows));
Mat roi2(final_img, Rect(img_loop.cols, img_loop.rows, rImg.cols, rImg.rows));
rImg.copyTo(roi2);
vImg[1].copyTo(roi1);
Why not using: http://docs.opencv.org/modules/stitching/doc/high_level.html#stitcher-composepanorama
It's available on 2.4.11 and 3.0.0.
The link you mentioned is access deniedhttp://www.cs.ucsb.edu/~holl/CS290I/Assignments/Assignments-3/Assignment3Mosaicing.html
.
what are 'img_loop' and 'Vimg' and 'rimg' in your code? there is some difference between your code and the code you linked.if it is possible explain a little so I can work on your problem , cause Im doing the same thing in opencv
I am new to c++ programming , today i was trying to save an image using CImg .
CImg is C++ Template Image Processing Library .
The basic code i wrote is(Please forgive any syntax erros , as copied part of my codes) :
#include "CImg.h"// Include CImg library header.
#include <iostream>
using namespace cimg_library;
using namespace std;
const int screen_size = 800;
//-------------------------------------------------------------------------------
// Main procedure
//-------------------------------------------------------------------------------
int main()
{
CImg<unsigned char> img(screen_size,screen_size,1,3,20);
CImgDisplay disp(img, "CImg Tutorial");
//Some drawing using img.draw_circle( 10, 10, 60, RED);
img.save("result.jpg"); // save the image
return 0;
}
But I cannot run my program as it says :
Invalid Parameter - 100%
'gm.exe' is not recognized as an internal or external command,
operable program or batch file.
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
[CImg] *** CImgIOException *** [instance(800,800,1,3,02150020,non-shared)] CImg<unsigned char>::save_other() : Failed to save file 'result.jpg'. Format is not natively supported, and no external commands succeeded.
terminate called after throwing an instance of 'cimg_library::CImgIOException'
what(): [instance(800,800,1,3,02150020,non-shared)] CImg<unsigned char>::save_other() : Failed to save file 'result.jpg'. Format is not natively supported, and no external commands succeeded.
Though i can see the image , I cannot save it.
After googling a bit i found people saying to install ImageMagick , i have installed it but no help .
Some of the Forum says to compile against libjpeg, libpng, libmagick++. But i don't know how to compile against those libraries.
I am using Eclipse CDT plugin to write C++ project .
Please help me .
I had the same error, and installing of GraphicsMagick (not ImageMagick) helped me.
I've downloaded and installed GraphicsMagick-1.3.26-Q8-win64-dll.exe from ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/windows/. You may choose another one, if you need:
Note that the QuantumDepth=8 version (Q8) which provides industry
standard 24/32 bit pixels consumes half the memory and about 30% less
CPU than the QuantumDepth=16 version (Q16) which provides 48/64 bit
pixels for high-resolution color. A Q8 version is fine for processing
typical photos intended for viewing on a computer screen. If you are
dealing with film, scientific, or medical images, use ICC color
profiles, or deal with images that have limited contrast, then the Q16
version is recommended.
Important: during installation, don't remove checkbox "Update executable search path", which updates environment variable %PATH%, making gm.exe available from any place.
In my case, it was also required to install Ghostscript - which is highly recommended to install by GraphicsMagick. There is a link to x64 Ghostscript: https://sourceforge.net/projects/ghostscript/files/GPL%20Ghostscript/9.09/gs909w64.exe/download (I've put it here, because links from the GraphicMagick websites leads you to 32-bit only).
After that, it worked fine for me.
For some image formats (as .jpg, .png, .tif and basically all formats that require data compression), CImg will try to use an external tool to save them (such as convert from ImageMagick or gm from GraphicsMagick).
If you don't have any installed, then you won't be able to save .jpg files without having to link your code with the libjpeg library, to get a native support for JPEG read/write (then, you'll need to #define cimg_use_jpeg before #include "CImg.h", to tell the library you want to use the libjpeg features).
If you want to keep things simpler, I'd recommend to save your image using another (non-compressed) image format, as .bmp or .ppm.
These formats are handled natively by CImg and do not require to link with external libraries.
I know this question is old, but I kept getting the same error on one project and not on another and this is the only thing on Google.
To get rid of it, you must do 2 things:
Install dynamic ImageMagick libraries for your appropriate OS and architecture(32/64). Link
I was using VisualStudio, and the character set must be set to "Unicode". The error would appear again when I reverted back to Multi-Byte character set. I guess this has something to do with the way CImg handles strings and miscompares them.
I am writing a program that uses OpenCV and involves intrinsic and distortion parameters. These parameters are loaded from .xml files saved on disc. I use the following commands in my opening declarations to load the files:
CvMat *intrinsic = (CvMat*)cvLoad("Intrinsics.xml");
CvMat *distortion = (CvMat*)cvLoad("Distortion.xml");
This works fine as long as the files are in the program's working directory. When they are not, the program crashes without any indication of the nature of the error. I have made the mistake of not having the xml files located correctly multiple times before, and I would like to make this easier to troubleshoot in the future.
I would like to create a guard against the files failing to load. Perhaps if they are not present my program could display an error message and exit gracefully. I saw the method suggested here, and it should work for me, but I was wondering if there was a cleaner way to do it without including another header.
For example, the OpenCV function cvQueryFrame returns 0 if it does not return a frame. I use the code
frame = cvQueryFrame(capture);
if(!frame)
{
printf("ERROR: Could not get frame from webcam.");
exit(-1);
}
to exit the program if cvQueryFrame fails to return a frame. I would like to do something similar with my matrix loading commands. Is this possible, and if so, how should I do it?
I checked the OpenCV documentation and could not find a description of cvLoad's behaviour when it cannot find the file specified so I am not sure how to proceed.
I am writing this project in C++ and running it on Windows 7.
It works. Go ahead and try it yourself:
CvMat *distortion = (CvMat*)cvLoad("Distortion.xml");
if (!distortion)
{
printf("!!! cvLoad failed");
exit(-1);
}
Hello I don t know if I am doing something wrong or not but when I do the following:
IplImage *testimage;
testimage = cvCreateImage(cvSize(10,10),IPL_DEPTH_8U,1);
cvThreshold(testimage,testimage,127,127,CV_THRESH_TRUNC);
everything works fine then when I try to use unsigned short values:
IplImage *testimage;
testimage = cvCreateImage(cvSize(10,10),IPL_DEPTH_16U,1);
cvThreshold(testimage,testimage,127,127,CV_THRESH_TRUNC);
my program crashes... I use opencv 2.4.2 I think this could maybe be a bug in opencv.
Somehow if I try the following:
IplImage *testimage;
testimage = cvCreateImage(cvSize(10,10),IPL_DEPTH_16S,1);
cvThreshold(testimage,testimage,127,127,CV_THRESH_TRUNC);
it doesn t crash anymore
It is not crashing. It is throwing an exception and since you are not catching it, your program is aborting.
OpenCV Thresholding does not support 16U.
The supported ones are: 8U, 16S and 32F
See the OpenCV documentation for function threshold. The first parameter is 8 or 32 bit image
P.S. In crash message you should see the reason for crashing