Window Function

Window function an important term in signal processing. It also called apodization or tapering function. It is useful for various operations, like separtion of band frequences etc.
Several different windows are available. Only two are worth using, the Blackman window and the Hamming window.
Blackman window are defined as,

w(n)= a0 – a1*cos((2*pi*n)/(N-1)) + a2*cos((4*pi*n)/(N-1));
where, 0<=n<=N .
and
a0=(1-@)/2, a1=1/2, a2=@/2. in blackman window @ equal to 0.16

Now , in case of Hamming windows coefficient are computed from following equation,

w(n)=0.54 – 0.46cos((2*pi*n)/N); where, 0<=n<=N.

Now for sample 74-point Blackman window’s time and frequency domain representation are given below,

Time domain of Blackman window

Time domain of Blackman window

Frequency domain of Blackman window

Frequency domain of Blackman window

For the same point Hamming window’s time and frequency domain is

Hamming window in Time domain

Hamming window in Time domain

Hamming window in Frequency domain

Hamming window in Frequency domain

In this case of blackman window Leakage factor is 0%, sidelobe attenuation -58.1dB and mainlobe width is (-3dB) : 0.0449.
for hamming, Leakage factor is 0.04%, sidelobe attenuation -42.5 dB and mainlobe width is (-3dB) : 0.0351.

After convolution this two windows we will get time and frequency domain like this,

Time domain

Time domain

Frequency domain

Frequency domain

Leakage factor is 0%, sidelobe attenuation -72.2dB and mainlobe width is (-3dB) : 0.0273.
so this result is more better than before. I called it FSwind πŸ™‚


Virtual FS :: New Website Launch

Finally πŸ™‚ I’m so much happy and excited to annouce the launch of my new site Virtual FS (VFS). It’s a Design, Portfolio and all about my artwork and enjoyment where I will get in touch with my clients and as well as my cutie, sweety , lovely friends and viewers. The main theme of Virtual FS is bring some different in my design. Those who already went my previous sites they can compare the differents of Virtual FS. Now this is an experimental version of VFS , Later will add more features……….
Don’t forget to give me a shout or comment . simply click VirtualFS.

Virtual FS Screenshot

Virtual FS Screenshot


Captcha Breaking :: Getting Naughty Once Again

Breaking CAPTCHA: Getting Naughty with Computer Vision……. And Captcha Breaking Experiment in PHP…. These terms now familiar to us. 1st one was made possible by Nadim vai and 2nd one by M. M. Rifat-Un-Nabi. Their post makes me inspire to get naughty once again more simply and more easily. Because I like simplicity ;). I also choosed SomeWhereInDhaka.Net Captcha to do this experiment.

P

That Captcha Which made me Naughty πŸ˜›

The SomeWhereInDhaka.Net CAPTCHA suffers several weaknesses: fixed font face, fixed font size, no distortions and it’s easy to segment. In this experiment, I have developed simple algorithm to break the SomeWhereInDhaka.Net CAPTCHA.

  1. At first need the captcha image from the page, We can do it in two way :

    (a) capturing only the captcha portion [I have used php function: imagejpeg()] or,

    (b) capturing the page image by php function and then crop only captcha portion from that page.

  2. So, we got that captcha. Now sampling that captcha image
  3. Match sampling pattern with reference pattern. If matching is true then it will give output, In this case the captcha value. (No need any edit distance algorithm)

I wrote a PHP+JavaScript code to implement this algorithm, which can read captcha and can fill up the form with out any human interaction.

Get Captcha Value with php

Get Captcha Value with php

And finally in bot section again JavaScript proved that its cool than anything.
I used simple JavaScript code which just read the HTML Tag and fill & submit the form automatically.

auto fill up the form by my bot

auto fill up the form by my bot

You can see the effect here.

I post my website ads πŸ˜› as spam. So, isn’t it more simple.

And finally a sympathy will goes for SomeWhereInDhaka.Net. And also I would like to thanks them because they not change there captcha yet. and it help me to make this experiment :D. So, my friends if wana see weak captcha then what are you waiting for – just log in to SomeWhereInDhaka.Net and keep getting naughty :P.


Make Vampiric hand for webpage

During the developing my homepage which is virtual FS, I was tried to bring some vampiric design on it. So, for that purpose I have create a hand which holding an old paper. I think it looks like vampiric :D.
It is very simple and it tooks only 20 min . Now.. lets see how it was happen…..

Hand Sketch:

At first I make a Hand sketch using normal Pen tool in PS. then after finishing sketch it looks like this…

Hand Sketch

Hand Sketch

Then its time to fill hand sketch with appropriate color. I choose #E9CF9B value for hand color.

Fill with Color

Fill with Color

Nail sketch And Add Shadow

Then Sketch nail and also fill with color #A38D1E. Then adjust color brightness, contrast, saturation, gradient map, curves; here I used
a parabolic curve. Then it becomes ….

Shadow and Nail

Shadow and Nail

Make Realistic

Now its up to you. How more and more realistic photo you can make.:)
I chooce an old paper and bring my hand art on it.

Final Touch

Final Touch

Finally I add this in to my homepage.

Virtual FS Homepage

Virtual FS Homepage

And thats it ……………… enjoy πŸ˜‰


“FS MUSIC MANIA” facebook app.

I think all of us know about facebook. A social networking site. Accoriding to Global Alexa page ranking Facebook postion is 5th. In my point of view, the best part of the facebook is facebook developer app. Its makes FaceBook more different and resouceful for developer.

Yestarday night I have spent some hours in FB APP. And I found some interesting and enjoyble variant-evolved subset of HTML FBML (FaceBook Markup Language), FBJS (FaceBook JavaScript) . I have developed a musical App which is
FS MUSIC MANIA. This is a musical application. People can listen music by using this app.

FS MUSIC MANIA Home page

FS MUSIC MANIA Home page

You can invite your friend. I have used FBML tagΒ <fb:multi-friend-selector> Which will allow you to invite multiple friend.

Invite your friend

Invite your friend

You can also add a profile box for FS Music Mania, in to your profile.
For this purpose simple need to add

$facebook->api_client->profile_setFBML(NULL, user_id, ‘profile’, NULL, ‘mobile_profile’, ‘profile_main’);

Then it will be like this………….(pic from fsmania)

Profile Box for FS Music Mania

Profile Box for FS Music Mania

So, Keep rocking with music and give me your feedback about FS Music Mania.
http://apps.facebook.com/fsmania/ πŸ˜€


Vector Graphics with Photoshop

Vector graphics formats are complementary to raster graphics, which is the representation of images as an array of pixels, as it is typically used for the representation of photographic images.
In short Raster is composed of pixels and Vector is composed of paths. Both are use in Graphics Designing. Now vector graphics,
It’s an important part in 3d Modeling, animations and graphics designing.
I found something more interesting and funny art in vector graphics with photoshop. Last night I have tried to make a vector graphics of my own picture:). And Now I would like to share this.

Its seem to me very interesting and much enjoyable. Although it doesn’t require any special ability you should be proficient in the use of the Photoshop or any other designing software. Your Drawing skills would also help can help you lot.

Vector Graphics of Md. Faisal

Main Photo

Md. Faisal

Sketch

First of all make a shape of the image. My photo shape like this….

Sketch main shape

Sketch main shape

Color is the Heart of Graphics

Choose body, cloth and other object color. And fill it. I choose #EACC2D for my body.

Body Color and Sketch

Body Color and Sketch

Face Color

Face Color

I think I have forget to do somthing πŸ˜‰ but what is that ……. Oh!! i got it.. I have forget to wear my eyeglass:).

And… Finally

Vector Graphics

That’s all :D. Don’t you think its so interesting.. After finishing this picture I also little bit surprised to see myself in vector graphics.

Update

another vector after 1 year. that same guy….

Peekaboo

Peekaboo


Peculiar message “Out Of Memery(OOM)”

A few days ago, some of my friends inform me , when they open my site www.engr-faisal.co.nr in IE7 or higher(in beta version) then their browser giving a message, which is “Out of memory at line ##”.

OOM showing in IE7( Vista OS )

OOM showing in IE7( Vista OS )


OOM in IE8 (BETA) and OS XP

OOM in IE8 (BETA) and OS XP

Actually I use Opera 9.23 as my default browser and also IE6 and others. But I never faced this type of problem. Even my site working pretty nice with all browser except IE7.

Actually “Out of memory(OOM)” case in modern computers when the operating system is unable to create any more virtual memory. If all of its potential backing devices have been filled. Such a system will be unable to load any additional programs and since many programs may load additional data into memory during execution, these will cease to function correctly.
The Operating systems such as Linux will attempt to recover from this type of OOM condition by terminating a low-priority process, a mechanism known as the OOM Killer.

This behavior can occur if the desktop heap in the WIN32 subsystem is depleted. Because in Windows NT 3.4’s default heap size is 512K , and 3072K in case of Windows NT 3.1.

Now how to remove this OOM message :(?
Okay .. To correct this problem, we may increase the size of the desktop heap. But before do this you have to know, how to modify the registry. Otherwise it can cause serious problems if you modify the registry incorrectly. For more information about how to back up and restore the registry you can read this article.
Now get ready………………

  • Run Registry Editor (simply open RUN window, then type regedit).
  • From the HKEY_LOCAL_MACHINE subtree, go to the following key: ->System->CurrentControlSet->Control->Session Manager->SubSystems
  • Select the Windows value.
    From the Edit menu, choose String.
    Increase the SharedSection parameter.
  • For Windows NT:
    SharedSection specifies the system and desktop heaps using the following format:
    SharedSection=xxxx,yyyy
    Add “,256” or “,512” after the yyyy number.
  • For Windows 2000, Windows XP, and Windows Server 2003:
    SharedSection uses the following format to specify the system and desktop heaps:
    SharedSection=xxxx,yyyy,zzz
    Increase the zzz number to “256” or “512.”
  • Hope this will help to prevent OOM.:)