OpenCV on OSX Mavericks with Xcode - c++

I'm trying to run OpenCV on OSX in Xcode. I have downloaded the code from github. And used cmake to compile it.
Next I created a new Xcode project with the following code:
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, char** argv )
{
if( argc != 2)
{
cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread("img.jpg"); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
Next I've set the header search path to: /usr/local/include
After that I've added the libraries from /usr/local/lib in the "Build Phases" as seen in the screenshot below.
(source: opencv.org)
However, when I try to run I get the following error:
ld: library not found for -lopencv_core.3.0.0
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Did I mis something?

In search for header path,
double tap the property. if you see the empty string
don't enter there,
slowly tap twice as it pop up a new list of properties
add the new one under the values press enter
still if its not working ,
check your string

You should add /usr/local/lib to the library search paths as well.

Related

OpenCV VideoCapture can't open file, what am I doing wrong?

I am compiling on Ubuntu 14.04 using OpenCV 3.1. When trying to open a video file it gives this error:
"Cannot open the video file"
I installed everything i could install : ffmpeg etc. Haven't found a solution checking out similar questions on StackOF.
What do ?
cv::VideoCapture cap(argv[1]);
Where argv[1] is the file name in the same directory as the executable.
In case your constructor is failing, you may want to use the .open() method. So, if you want to open a file that is called "myVideo.mp4" that is in the folder of your project, you would do the following:
cv::VideoCapture cap;
cap.open("myVideo.mp4");
For more detailed informations about this method, check this documentation link
Also, the book Learning OpenCV 3, from the O'Rilley media, on page 26 gives you a good example. Here is a Gist that I made to give you as an example.
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
int main() {
cv::VideoCapture cap;
cap.open("myVideo.mp4" );
cv::namedWindow( "myVideo", cv::WINDOW_AUTOSIZE );
cv::Mat frame;
while(true) {
cap >> frame;
if( frame.empty() ){
std::cout << "Could not load the video frames. \n";
break;
}
cv::imshow( "myVideo", frame );
if( cv::waitKey(27) >= 0 ){
std::cout << "Escape pressed \n";
break;
}
}
return 0;
}

imread couldn't find image

I use visual studio 2013 and opencv. I run a simple code that reads a image and shows it. I add the image to resource files of my project from Donloads file. When I run below code, image.data is empty.
#include "stdafx.h"
#include <opencv2\core\core.hpp>
#include <opencv2\highgui\highgui.hpp>
#include <opencv2\opencv.hpp>
int _tmain(int argc, _TCHAR* argv[])
{
cv::Mat image;
image = cv::imread("im.png", CV_LOAD_IMAGE_COLOR); // Read the file
if (!image.data) // Check for invalid input
{
std::cout << "Could not open or find the image" << std::endl;
return -1;
}
cv::namedWindow("Display window", cv::WINDOW_AUTOSIZE);// Create a window for display.
imshow("Display window", image); // Show our image inside it.
cv::waitKey(0); // Wait for a keystroke in the window
return 0;
}
Try : C:\\Users\\pr\\Downloads\\im.png that should work if the path is correct.
This is because the default working directory in VS is the location of your vcxproj file (value of $(ProjectDir)).
If you would like to start your application through VS (i.e. by F5 key) then you should overwrite the debugging parameters of your project. For example you can set the application's working directory to the location of the program (exe) that the linker creates by setting the value of Project menu -> Properties -> Configuration properties -> Debugging -> Working directory to $(OutDir).

Trouble reading image OpenCV

I'm following the tutorial here for setting up OpenCV with Visual Studio (I have 2013 Community edition and OpenCV 2.4.10).
I have the following folder structure:
OpenCVTest
-OpenCVTest.sln
+x64
+Debug
- opencv_core2410d.dll
- opencv_highgui2410d.dll
- OpenCVTest.exe
- OpenCVTest.ilk
- OpenCVTest.pdb
- feck.png
And my source:
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
if (argc != 2)
{
cout << " Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], IMREAD_COLOR); // Read the file
if (!image.data) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl;
return -1;
}
namedWindow("Display window", WINDOW_AUTOSIZE); // Create a window for display.
imshow("Display window", image); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
When I run this in VS or on the command line, I get the following error:
C:\Users\mr\Documents\Visual Studio 2013\Projects\OpenCVTest\x64\Debug>OpenCVTest.exe feck.png
Could not open or find the image
Anybody know why this might be happening?
Update
I have tried giving the full path:
image = imread("C:\Users\mr\Documents\Visual Studio 2013\Projects\OpenCVTest\feck.png", IMREAD_COLOR); // Read the file
and placing the image at the same level as the .sln file, still no luck.
Place your image in OpenCVTest folder like this:
C:\Users\mr\Documents\Visual Studio 2013\Projects\OpenCVTest\OpenCVTest\feck.png
-OpenCVTest.sln
-OpenCVTest <- **HERE**
-ipch
+x64
+Debug
- opencv_core2410d.dll
- opencv_highgui2410d.dll
- OpenCVTest.exe
- OpenCVTest.ilk
- OpenCVTest.pdb
- feck.png
In the tutorial here, under "The local method", it reads:
Then you need to specify the libraries in which the linker should look
into. To do this go to the Linker ‣ Input and under the “Additional
Dependencies” entry add the name of all modules which you want to use:
opencv_core231d.lib
opencv_imgproc231d.lib
opencv_highgui231d.lib
opencv_ml231d.lib
opencv_video231d.lib
opencv_features2d231d.lib
opencv_calib3d231d.lib
opencv_objdetect231d.lib
opencv_contrib231d.lib
opencv_legacy231d.lib
opencv_flann231d.lib
I changed these from opencv_core{version}d.lib to opencv_core{version}.lib (not the debug library) and it seems to work okay now. I can step through the code in Visual Studio and the code appears to work.

imread in OpenCV

I found that this question has been asked many times here, but I haven't found any solution or work-around to this problem. Here's my code (copied from here: http://docs.opencv.org/doc/tutorials/introduction/display_image/display_image.html):
#include <iostream>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
using namespace cv;
using namespace std;
int _tmain(int argc, char** argv)
{
if( argc != 2)
{
cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
namedWindow( "Display window", WINDOW_AUTOSIZE ); // Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
I compiled this using Visual Studio 2008 and 2010, and got different results (both don't work). The program compiled using VS 2008 has run-time error at imread(), and the other displays the message "Could not open or find the image".
Anybody can help me with this?
The problem here is your main() function._tmain does not exist in C++. main does.
_tmain is a Microsoft extension. Here is a nice explanation of these two methods.
Further more if you want to add default argument in Visual studio please follow these steps.
Right click your project in Solution Explorer and select Properties from the menu
Go to Configuration Properties -> Debugging
Set the Command Arguments in the property list.
Hope this solves your problem!
#include <iostream>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
using namespace cv;
using namespace std;
int main(int argc, char **argv)
{
if( argc != 2)
{
cout <<"No Commandline Aurgument Found!: Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
namedWindow( "Display window", WINDOW_AUTOSIZE ); // Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
set argv[1] to be a known image page "C:\test.jpg"
Ok, Ive read all the comments and I'm going to answer the main question along with the sub questions.
Why Doesn't my Code Work in VS2008?
The reason your code doesn't work in VS2008 is because you are using the compiled libraries for 2010, at least I think this is a pretty accurate assumption. If you want to be completely accurate then build the libraries, for the compiler you are using.
What is tmain & what is main
This stack overflow question answers the subject a lot better than I ever could, but effectively it is a windows specific main and does not actually exist in C++. It get removes by the compiler on compile time and converter to main.
Can you please try this: Use known-to-work image and absolute path until it works so you can be sure that there is no problem with image or relative path.
download http://upload.wikimedia.org/wikipedia/en/2/24/Lenna.png to C:\Lenna.png
rename your main function to something else and try this: if it does not work, please tell me the displayed name of the output window.
#include <iostream>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
using namespace cv;
using namespace std;
int main(int argc, char **argv)
{
namedWindow( "Display window", WINDOW_AUTOSIZE ); // Create a window for display.
Mat image;
image = imread("C:/Lenna.png", CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.cols ) // Check for invalid input
{
cout << "Could not open or find the image. Press any key to exit." << std::endl ;
cv::waitKey(0)
return -1;
}
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
Please try this and if it does not work, please tell me the displayed name of the output window.

OpenCV: Error for failure to load library libopencv_calib3d.2.4.dylib

I am trying to set up openCV (installed with homebrew) on my mac and ran the following the command.
g++ $(pkg-config --cflags --libs opencv) test.cpp -o Test& ./test
However, I got this error:
[1] 7834
dyld: Library not loaded: lib/libopencv_calib3d.2.4.dylib
Referenced from: /usr/local/Cellar/opencv/2.4.9/include/./test
Reason: image not found
Trace/BPT trap: 5
I'm not sure what to do take care of this issue very novice to openCV and C++.
The following shows the file structure. The test.cpp file is 2nd from the right along with the picture. I don't see how the program isn't finding the file as the name and location seem to be correct.
test.cpp:
#include "opencv2/highgui/highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, const char** argv )
{
cout << "test output line" << endl;
Mat img = imread("MyPic.JPG", CV_LOAD_IMAGE_UNCHANGED); //read the image data in the file "MyPic.JPG" and store it in 'img'
if (img.empty()) //check whether the image is loaded or not
{
cout << "Error : Image cannot be loaded..!!" << endl;
//system("pause"); //wait for a key press
return -1;
}
namedWindow("MyWindow", CV_WINDOW_AUTOSIZE); //create a window with the name "MyWindow"
imshow("MyWindow", img); //display the image which is stored in the 'img' in the "MyWindow" window
waitKey(0); //wait infinite time for a keypress
destroyWindow("MyWindow"); //destroy the window with the name, "MyWindow"
return 0;
}
Figured it out. Took the .dylib files from /usr/local/Cellar/opencv/2.4.9/lib duplicated and pasted them into /usr/lib.
copy all lib file ie in .dll format past it into your project folder.it will read all the neccessar file from that folder