AR0x7E7's profile - activity

Hello everybody,

using Opencv 2.4.9 on Windows 7 64 bit in combination with two Sony PS3 Eye Multi Webcams it seems like Opencv has problems to access both cams.

Clearly I installed Code Laboratories latest CL Eye Platform Driver and CL Eye Platform SDK.

USING CL Eye Platform

Running the provided CLEyeMulticamTest.exe both cams work flawlessly (see screenshot attached).

USING OPENCV

However, using following simple OpenCV example it turns out only one PS3 Eye can be selected (see screenshot attached).

int main(int nargs, char** argv)
{
int id = std::stoi(argv[1]);

cv::VideoCapture cap(id); // open passed cam id
if(!cap.isOpened())  // check if we succeeded
    return -1;

cv::Mat edges;
cv::namedWindow("edges",1);
for(;;)
{
    cv::Mat frame;
    cap >> frame; // get a new frame from camera
    cvtColor(frame, edges, CV_BGR2GRAY);
    GaussianBlur(edges, edges, cv::Size(7,7), 1.5, 1.5);
    Canny(edges, edges, 0, 30, 3);
    imshow("edges", edges);
    if(cv::waitKey(30) >= 0) break;
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;

USING OPENCV with two diffrent cams

When I plug in another Webcam (Logitech) Opencv can access both of them:

USB Hub Config

To make things clear I also made sure to identify USB Ports connected to different controllers (I read something about 100% bandwidth usage of a single cam leading to problems using more cams on same usb hub)

the final question is

So can somebody qualified tell me whether this behavior is the current state of things when it comes to use OpenCV with two PS3 Eye Cams or is there some neath trick left?

I understand that using CL SDK I will be able to utilize both cameras. However, it would be nice to use OpenCV as a wrapper instead ;).

Kind regards AR

For me its working (remember videos are 0-based indexed):

using namespace std;
using namespace cv;


int main() {
    VideoCapture cap("test.mp4");
    if( !cap.isOpened()){
        cout << "Cannot open the video file" << endl;
        return -1;
    }

int count = (int) cap.get(CV_CAP_PROP_FRAME_COUNT); //get total frame count
cout<< "Max frames: "<< count << endl;

Mat frame;
int index = 0;
while(cap.read(frame))
{
    cout << "the current frame: " << index << endl;
    index++;
}
cout << "exit first loop" << endl;
cap.set(CV_CAP_PROP_POS_FRAMES, 0); //Set index to 0 (start frame)
int index2 = 0;
while(cap.read(frame))
{
    cout << "the current frame: " << index2 << endl;
    index2++;
}
cout << "exit second loop" << endl;
cout << "index1: "<< index << " / index2: "<< index2 <<endl;
}

Output (see attached mp4 file C:\fakepath\test.mp4.jpg for own test, rename it to .mp4 ;-) ):

Max frames: 145
..
index1: 145 / index2: 145

Note: I don't use Java in combination wit opencv, but it should work like this:

If the procedure you described really is in the same method scope you could simply extract the letters behind the last '.' of the path from the image path you pass to _imread_ - i.e. 'jpg' from "h:\opencv.jpg" - and then pass it on to _imencode_

For this to work you need to save the path of the image loaded, i.e.

String image_in = "h:/opencv.jpg";
Mat image = Highgui.imread(image_in);

Later you use i.e. String.split function

String[] image_in_splits = image_in.split(".");
String fileFormat = image_in_splits[image_in_splits.length - 1];

sorry, but I don't think that I understand your question properly: do you want to draw a rectangle _around a pixel of certain value_ or around an _object_? It the latter one, how do you get/define that _object_?

StevenPuttemans, can you please accept the answer below and close the question? I lack sufficient reputation ;D Of course you can check my solution first.

In order to deactivate the right click context menu using opencv 2.4.9 namedWindow with Qt 5.2.1 search for file:

opencv\sources\modules\highgui\src\window_QT.cpp

find the following function (usually line 2514):

void DefaultViewPort::contextMenuEvent(QContextMenuEvent* evnt)
{
    if (centralWidget->vect_QActions.size() > 0)
    {
        QMenu menu(this);

        foreach (QAction *a, centralWidget->vect_QActions)
            menu.addAction(a);

        menu.exec(evnt->globalPos());
    }
}

set it to (alternatively just comment the inside of function):

void DefaultViewPort::contextMenuEvent(QContextMenuEvent* evnt)
{
    return;
}

recompile opencv, done.

looks like your setup for "Additional Include Directories" at "Configuration Properties -> C/C++ -> General" is wrong - more information needed: what's your current PATH, where is your opencv directory?

I.e. my setup (Win7 64 bit, VS2012, opencv 2.4.9):

"Additional Include Directories": $(OPENCV_DIR)\include

Win7 System Variables:

OPENCV_DIR: C:\opencv\build PATH: %OPENCV_DIR%\bin;

You should not copy paths from tutorials blindly, but refactor them to your own system. Look out for '\' use everywhere instead of '/'.

Sorry, but how should the while loop ever terminate? I dont think this can work, as the loop exit condition will never be satisfied

so I found the appropriate part of code to comment =) Unfortunately, I have to wait until tomorrow until I can answer my own question :D

Hi wuling and thanks for your reply, while it would be surprising for me to see your suggestion work, I still gave it a try and disabled Cmake OpenGL (see Updated setup of mine with qt-opensource-windows-x86-msvc2010_opengl-5.2.1.exe) However, at runtime: OpenCV Error: No OpenGL support (Library was built without OpenGL support) ..

Yes, this might be plan B - however, I'm a programmer, this whole software is open source, so In my opinion it has to be possible and it might just be a few loc in need to be commented (i.e. the switch statement which handles the mousrightbuttonclick event triggering the context menu to appear) and my mission will be accomplished :P

Hi StevenPuttermans and thanks for your reply, unfortunately I'm in need of the Qt enhanced GUI functionalities (like resize window, zoom in/out, take picture). Therefore, building opencv with qt is a must.

Hello all,

I'm looking for a way to disable the context menu when right clicking on namedWindow (see http://docs.opencv.org/modules/highgui/doc/qt_new_functions.html for clarification)

The reason is, I want to use the right mouse button for some user interaction but the menu keeps popping up and is therefore disturbing havily.

I also tried to identifiy the part of opencv source code (QT_window.cpp) where the callback function with rightbuttonup is set - as you might guess, unsuccessfully.

Thank you for any help.

Kind regards AR