Archive for November, 2009
OpenCv library is really a great help in programing a web-cam.I tried to access a web-cam through a C code and was succesfull in doing it.Before the code can be executed and the web-cam can be accesed ,a library named ‘opencv’ is to be installed .
OpenCV (Open Source Computer Vision) is a library of programming functions for real time computer vision . OpenCV is released under a BSD license, it is free .
The library is available in debian distro cd’s and can be installed by issuing the commands
apt-get install opencv*
apt-get install libhighgui*
apt-get install libaux-dev
- Program in C to access web-cam, Capturing and Saving image
The web-cam can be accessed in C and the images saved is in .jpg format
A simple program to see the video accessed by the webcam.
My Cheese app in C.
#include < opencv/cv.h >
int main(int argc,char **argv)
CvCapture* cap = cvCreateCameraCapture(0);
image1 = cvQueryFrame(cap);
//waiting 33 milliseconds for a key to be pressed
char c = cvWaitKey(33);
//if the key pressed is esc
//ascii of esc is 27
//if the key pressed is an up-arrow key
else if(c ==’82’)
image2 = image1;
Compile the above code by executing the command:
gcc -o cheese_in_c cheese.c `pkg-config opencv --cflags --libs `
this command creates an executable named “cheese_in_c”.
Execute the executable as
this program displays a window named “rohit”showing the pictures taken from the webcam,then it waits for 33 milliseconds for the user to press a key.If key pressed is ‘up-arrow’ the picture from the camera is captured and saved in the same directory in the name “my-photo.jpg”.
I ‘m using a wireless Internet connection (BSNL WLL connction).This post may be of use to newbies in linux ,trying to connect to internet through a dial up connection.The first step to be done is
- To install ‘wvdial’
In debian distro, the package is available in their distribution cd.For installation try the command
apt-get install wvdial
the package can be downloaded from the link below
the package can then be installed as
dpkg -i wvdial-xx.deb
- configuring the file /etc/wvdial.conf
now the file /etc/wvdial.conf has to be configured according to connection requirements ,the overall structure of the /etc/wvdial.conf can be obtained from link
my wvdial.conf file looks like the one below
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = at+crm=1;+cmux=1;+cps=33;+cta=0
Stupid Mode = yes
ISDN = 0
Modem Type = USB Modem
New PPPD = yes
Phone = #777
Modem = /dev/ttyUSB0
Username = xxxxxxx
Password = xxxxxxx
Baud = 460800
here in the file for the users using BSNL – WLL connection have to replace
username and password provided to them by the service provider
Username = xxxxxxxx
Password = xxxxxxxx
now to be able to use the connection ,first we have to register the dial-up modem to their kernel.as provided in the link
then the user can browse onto internet by just dialing
in the terminal.
For mounting a disk partition in linux formatted as NTFS file system in read/write mode or any other file system in debian, NTFS-3g can be of a great use.For using this to be used the packages are supposed to be installed onto the operating system by first adding all the debian distribution CD’s to the synaptic manager followed by using the command.
apt-get install ntfs-3g
The package ‘NTFS-3G’ can be installed either from debian lenny distribution CD’s .by first
Root previledge is needed for the below commands.
- first make the destination folder anywhere you want (as i made my destination folder as /media/disk1)
- if you are having a sata hard-disk then try the command
mount -t ntfs-3g /dev/sda5 /media/disk1
if you are having an IDE hard disk then try the command
mount -t ntfs-3g /dev/hda5 /media/disk-1
- Mounting disk drives at the startup
For mounting disk drives at boot-up time. The file /etc/fstab has to be configured .In the file ,under the type bar the file system for ntfs is to mounted under ntfs-3g system.
Next week,I am having an examination of Computer hardware lab where all we people are supposed to do
assembly level coding for X86 architecture.In our lab, we used to do coding in Ms-WindowsXp using a software “NASM.exe” (an assembler),although our staff prefers open-source over a proprietory software.
Only hardware lab was there in our college which was still having MS-windows installed on it,all other labs are having open source OS installled in their PC’s.As no awareness about free software version of NASM and DOSEMU was there with our staff.
This was the time when one of my friend and classmate Harikrishnan suggested them about packages “Dos-Emu” in LINUX environment
Now ,govt engineering college sreekrishnapuram is one of those engineering colleges in our country where all the computer labs are having open source operating system on each of it’s computer.
The package “dosemu” is available in the latest version of almost every linux distro’s.
For Debian 5.0 lenny the package is available in the cdrom itself,otherwise can be downloaded from the link
the rpm version for redhat distros and package.tar.gz is available at the link
I installed it on one of my friend’s PC having a debian lenny distro.As the package was available with the distro cd ,all i needed to do was to add cdrom in synaptic manager and install the package dosemu.
- Adding a cdrom in Synaptic Package Manager
System – Administration
click open the
Synaptic Package Manager
this will prompt for the root password,as the procedure needs root previlege
under the edit tab there is an option “add cdrom”,this may prompt for inserting a cdrom to be added if it is not already inserted.After the cdrom is inserted all the indexes of the package will added into the package list.
- Installation of dosemu
then package “dosemu “can be installed from the Synaptic Package Manager or it can be instatlled by
sudo apt-get install dosemu
the package will be installed and the dos emulator can be accesed by typing a command
in the shell.
This will create a “.dosemu ” directory in your login directory (in /home/… directory).In that directory it will create a drive_c directory where the “dosemu ” works .
I hope that this will be a bit usefull to those who are trying to switch onto open-source environment from windows environment like me
- nasm installation in debian
The package NASM is available with debian lenny distro CD.and is available at
can be installed from debian distro cd as
sudo apt-get install nasm
any .asm file can be assembled by NASM as
nasm file.asm -fbin -o file.com
which creates a file file.com
this file.com can be executed by executing the file’s name on “dosemu” prompt.