SSH Without Password Prompt

Assume you want to 'scp' from machine A to B:

A > vi ~/.ssh/id_rsa.pub
Copy all text in id_rsa.pub

B > vi ~/.ssh/authorized_keys
Append copied text to end of authorized_keys


OR

A > scp ~/.ssh/id_rsa.pub username@ip_of_B:
B > cat ~/id_rsa.pub >> ~/.ssh/authorized_keys
B > rm ~/id_rsa.pub

Save OpenCV 2.4.6 Configs in a Property Sheet, VS2012

Pre Requirements:

Improtant: If you are building a x86 application (even though windows platform of the programming machine is x64), you must use "For x86" sections of the article. You can find or change the application platform  from Build -> Configuration Manager -> Active Solution Platform after you create the project.

• Download the latest OpenCV version from  http://opencv.org/downloads.html 
• Extract it. ( C:\opencv )
• Start -> Right click My Computer -> Properties -> Advanced System Settings -> Environment Variables 
• Select Path in System Variables. Add the following line.

For x86

;C:\opencv\build\x86\vc11\bin

For x64

;C:\opencv\build\x64\vc11\bin

• Save it.
• Restart Windows

Now opencv is ready to use in your computer.

Add property page

• Start new C++ console project in Visual Studio 2012
• View --> Property Manager (Property Manager will appear to side plane)
• Right click Debug --> Add New Project Property Sheet
• Name the property sheet, OpenCV.props
• Select tab, C++ --> General
• Add the following line to Additional Include Directories

C:\opencv\build\include

• Select tab, Linker --> General
• Add the following line to Additional Library Directories

For x86
C:\opencv\build\x86\vc11\lib

For x64
C:\opencv\build\x64\vc11\lib

• Select tab, Linker --> Input
• Add the following lines to Additional Dependancies

 opencv_core246d.lib

opencv_imgproc246d.lib

opencv_highgui246d.lib

opencv_ml246d.lib

opencv_video246d.lib

opencv_features2d246d.lib

opencv_calib3d246d.lib

opencv_objdetect246d.lib

opencv_contrib246d.lib

opencv_legacy246d.lib

opencv_nonfree246d.lib

opencv_flann246d.lib 

• Click OK
• You have finished configuring. Test OpenCV

#include "stdafx.h"
#include "opencv2\imgproc\imgproc.hpp"
#include "opencv2\core\core.hpp"
#include "opencv2\highgui\highgui.hpp"

using namespace cv;

int _tmain(int argc, _TCHAR* argv[])
{
    Mat img = imread("C:\\Users\\Public\\Pictures\\Sample Pictures\\Koala.jpg");
    imshow("Display",img);
    waitKey();
    return 0;
} 

Reuse the Property Sheet 

• Go to the project location in Windows Explorer.
• You will find a OpenCV.props file.
• Back up the file.

  When you create another OpenCV project,

• Start new C++ console project in Visual Studio 2012
• View --> Property Manager (Property Manager will appear to side plane)
• Right click Debug --> Add Existing Project Property Sheet
• Locate your backed up OpenCV.props file.
• Now all OpenCV configurations are added to the project.
• Test with the above code.

Have fun !!!
 

Run Console Application in Qt Creater

There is a bug when you try to run in terminal, it does not take any input or output.

To fix this bug on Ubunut,

Tools --> Options --> Environment --> General 

Change the Terminal from
x-terminal-emulator -e
to
/usr/bin/xterm -e

Thanks to https://bugs.launchpad.net/ubuntu/+source/qtcreator/+bug/566387

Install OpenCV 2.4.5 on Visual C++ .NET 2010

Improtant: If you are building a x86 application (even though windows platform of the programming machine is x64), you must use "For x86" sections of the article. You can find or change the application platform  from Build -> Configuration Manager -> Active Solution Platform after you create the project.

• Download the latest OpenCV version from  http://opencv.org/downloads.html 
• Extract it. ( C:\opencv )
• Start -> Right click My Computer -> Properties -> Advanced System Settings -> Environment Variables 
• Select Path in System Variables. Add the following line.

For x86

;C:\opencv\build\x86\vc10\bin

;C:\opencv\build\common\tbb\ia32\vc10 (Only if the folder exists)

For x64

;C:\opencv\build\x64\vc10\bin

;C:\opencv\build\common\tbb\intel64\vc10 (Only if the folder exists)

• Save it.
• Restart Windows

• Start new c++ console project in Visual Studio 2010
• Project -> Properties
• Select C++ -> General tab
• Add the following lines to Additional Include Directories

C:\opencv\build\include\

C:\opencv\build\include\opencv

• Select Linker -> General
• Add the following lines to Additional Library Directories

For x86
C:\opencv\build\x86\vc10\lib

For x64
C:\opencv\build\x64\vc10\lib

• Select Linker -> Input
• Add the following to Additional Dependencies in Debug Configurations.

(245 is for opencv version 2.4.5. Change it appropreately for opencv version)

opencv_core245d.lib

opencv_imgproc245d.lib

opencv_highgui245d.lib

opencv_ml245d.lib

opencv_video245d.lib

opencv_features2d245d.lib

opencv_calib3d245d.lib

opencv_objdetect245d.lib

opencv_contrib245d.lib

opencv_legacy245d.lib

opencv_nonfree245d.lib

opencv_flann245d.lib 

• Add the following to Additional Dependencies in Release Configuration, if you want to build a release version. (Not required)

opencv_core245d.lib

opencv_imgproc245.lib

opencv_highgui245.lib

opencv_ml245.lib

opencv_video245.lib

opencv_features2d245.lib

opencv_calib3d245.lib

opencv_objdetect245.lib

opencv_contrib245.lib

opencv_legacy245.lib

opencv_nonfree245.lib

opencv_flann245.lib

•  Opencv is ready to use. Try the following example

#include "stdafx.h"

#include "opencv2\core\core.hpp"

#include "opencv2\imgproc\imgproc.hpp"

#include "opencv2\highgui\highgui.hpp"

using namespace cv;

int _tmain(int argc, _TCHAR* argv[])

{

 VideoCapture cap(0);

 do{

  Mat img;

  cap >> img;

  imshow("Disp",img);

 }while(waitKey(30)<0);

 return 0;

}

OpenCV on Android

First of all, you need JDK installed on your computer. (JRE is not sufficient). Unless download and install it.
http://www.oracle.com/technetwork/java/javase/downloads/index.html 

You definelty need android SDK ADT Bundle. 
http://developer.android.com/sdk/index.html

Simply extract it. Open Adroid SDK Manger from <extracted path>. Android 3.0 or higher must be installed.   

<extracted path>\eclipse\eclipse.exe is your IDE.

First time you start eclipse IDE it will ask you to select working directory. (Close the welcome page) Working directory is the place you save you android projects. Therefore select a known <working directory> path.

If you do not have experience in android programming, do go through this article,
http://developer.android.com/training/basics/activity-lifecycle/starting.html
because android is not like a simple c program, it is a state machine.


Now it is the time to download OpenCV-Android-SDK from here,
http://sourceforge.net/projects/opencvlibrary/files/opencv-android/2.4.3/OpenCV-2.4.3.2-android-sdk.zip/download

Extract it to <working directory>.  

Now you your installations are ready. Open Android Eclipse IDE. 
File -> Import -> General -> Existing Projects into Workspace -> Next

Set the root directory path as OpenCV Android SDK folder. In the figure above "E:\AndroidOpenCV\" is my working directory.

From the projects list, only select the ones I have selected if you are new and finish it. Others require Android NDK.

First one in the list, OpenCV Library, is the most important. It must be in your working directory every time you build a OpenCV project. Others are some examples comes with OpenCV, that you can learn a lot from them.

If everything goes well you must see a screen like this. If so you are lucky and you can skip to Run Example Section of this post. 

In some case you will not be such lucky, and there will be some error on the screen.

First of all make sure OpenCV Library is on you Package Explorer. 

Right Click OpenCV Library on Package Explorer -> Properties

In Android tab check whether at least one project target is selected above Android 3.0

In Java Compiler tab check the java version is correctly configured. 

Then errors in OpenCV library must be eliminated. 

Then Right click a sample (OpenCV-Sample-image-manupilations) on Package Explorer -> Properties

In Android tab check whether at least one project target is selected above Android 3.0

and OpenCV Library is added as in this figure.

Run Example

This is what I summarized here.
http://developer.android.com/training/basics/firstapp/running-app.html

Run On Emulator

In your Eclipse IDE, 
Window -> Android Virtual Device Manager -> New

Set as above figure and OK 
Select TestAVD you created -> Start
Close Virtual Device Manager.

In Package Explorer in Eclipse IDE, 
Right click the OpenCV - Sample - image-manipulations -> Run As -> Android Application.

This will run the application on your emulator :)


Run On Real Device

First of all you need an Android Device with Android 3.0 or higher and you must have USB drivers installed. Unless get them from manufactures website or may be here, http://developer.android.com/tools/extras/oem-usb.html . 

Turn on Debugging mode on you android device. For example, in Samsung Galaxy, 
Settings -> Developer Options -> Check USB Debugging, Check Allow mock locations.

Then connect your phone to computer.


In Package Explorer in Eclipse IDE, 
Right click the OpenCV-Sample-image-manipulations -> Run As -> Android Application.

If prompt select your real device. Then application will be installed and run on your device. 

In the first time use it will automatically download OpenCV Manager from Google Play.

The OpenCV sample will be running on you real device. Try Edge detection on your android device :)


These are the Tutorial provided from OpenCV. They may also helpful to you.
http://docs.opencv.org/doc/tutorials/introduction/android_binary_package/O4A_SDK.html#o4a-sdk
http://docs.opencv.org/doc/tutorials/introduction/android_binary_package/android_dev_intro.html

Configure OpenCV 2.4 for Qt Creator on Ubuntu

First install Qt creator using Ubuntu Software Center

Open Qt Creator

File --> New file or project
Qt Widget Project --> Qt GUI Application --> Choose

Click Next for all.

Open .pro file and add the following lines

INCLUDEPATH += /usr/local/include/opencv
LIBS += -L/usr/local/lib
LIBS += -lopencv_core
LIBS += -lopencv_imgproc
LIBS += -lopencv_highgui
LIBS += -lopencv_ml
LIBS += -lopencv_video
LIBS += -lopencv_features2d
LIBS += -lopencv_calib3d
LIBS += -lopencv_objdetect
LIBS += -lopencv_contrib
LIBS += -lopencv_legacy
LIBS += -lopencv_flann
LIBS += -lopencv_nonfree

Save it.

Open .ui file.

Drag and drop a PushButton to window.
Click PushButton and chage the follwong properties

• objectName: btnDisplay
• text: Display

Right click PushButton --> Go to slot --> clicked() --> Ok

Include the following

#include <cv.h>
#include <highgui.h>

Add the following code

void MainWindow::on_btnDisplay_clicked()
{
    cv::namedWindow("Disp");
    cv::VideoCapture cap(0);
    cv::Mat frame;
    do{
        cap >> frame;
        imshow("Disp",frame);
    }while(cv::waitKey(30)<0);
    cv::destroyAllWindows();
}

Run it. You will see yourself on the screen, when you click Display button !!!

Configure OpenCV 2.4 for Eclipse

Open Eclipse IDE

File --> New --> C++ Project

Give a project name
Select project type Hello World C++ Project from Executables

Project --> Properties
C/C++ Build --> Settings

Cross G++ Compiler --> Includes
Add /usr/local/include/opencv to Include paths(-l)

Cross G++ Linker --> Libraries
Add /usr/local/lib to Library search path (-L)
Add the following to Libraries(-l)

opencv_core
opencv_imgproc
opencv_highgui
opencv_ml
opencv_video
opencv_features2d
opencv_calib3d
opencv_objdetect
opencv_contrib
opencv_legacy
opencv_flann
opencv_nonfree

Copy the following test app, build and run.

#include <iostream>
#include <cv.h>
#include <highgui.h>

using namespace std;
using namespace cv;

int main() {
    cout << "!!!Hello World!!!" << endl;

    VideoCapture cap(0);
    Mat frame;
    do{
        cap >> frame;
        imshow("Disp", frame);
    }while(waitKey(30)<0);

    return 0;
}

It works !