iPost

Apple Media Event?

2011-09-26T15:17:00.002+02:00

It seems that Apple’s iPhone media event is scheduled for 4th of October and will be held at company’s headquarters in Cupertino, California rather than Yerba Buena Center for the Arts in San Francisco.

3D Object Point Detection - 3D Laser Scanner

2011-08-26T21:55:00.000+02:00

With use of laser line equations from previous step we can draw laser lines. Difference between the laser lines and images of only red laser pixels will give us the object points. Now we want to get the 3D point cloud. The Intrinsic and Extrinsic Parameters from first step is utilized here to find the 3D point cloud. First we have to find the laser plane by taking 3 non-collinear points from the laser lines, then the 3D coordinates will be the intersection of the laser plane and the object. Afterwards the color of the object points can be added to the point cloud from the reference image.

I use the SLAM6D as a 3D Toolkit to show the point cloud which is an open source program and can be downloaded from here.

SLAM6D is also capable of registering several point clouds with ICP algorithm in this case and put all of them in the same reference frame, however for this purpose we need to get a several scans of our object with small rotational angle, and after calculating the 3D point cloud of each scan the ICP algorithm will take care of the rest and register them together in order to create one rigid 3D object.

OS X Lion

2011-07-08T21:42:00.002+02:00

According to macrumors Apple may be preparing its retail stores for a launch of OS X Lion next week, with MacBook Air and other hardware updates likely to follow alongside or soon after the new operating system debuts.

9 to 5 mac reports that Apple retail stores are planning ‘overnights’ on July 13th. Overnights are generally where Apple refreshes store displays and trains up management on new products.

Laser Line Detection - 3D Laser Scanner

2011-04-15T13:39:00.000+02:00

Laser line detection can be done in 3 steps. These steps are should be processed on each frame sequence of our video.

1. Frame difference: Since the background is static in our video and the only thing that is changing is the laser line in each frame, So by finding the difference of two sequential frames we should be able to separate the laser line from the background. For this purpose we can utilize the cvSub function between an image with laser line on it and a reference image with out a laser line. We can use the cvSmooth before diff process to get the better segmentation of laser line.

2. Laser Color: As the above image shows the result image from difference process contain objects other than laser line so we need one more step of process to be able to segment the laser line from background. Since the laser line has red color we aim for finding only red color in our image. This can be achieved by going through all the pixels and check the color of them and if it has a color in specific range we consider it as laser point other than that we change the color of it to black. The result of this step is an image with only red pixels of laser lines.

3. Laser Line: This step is the process of finding the laser line equations. We start it by creating smoothed image from the previous step. Proceed with Canny Edge Detection and by using the cvHoughLines2 function with CV_HOUGH_PROBABILISTIC option of OpenCV we are able to find the laser lines equations. The result of this step is an image with lines founded by cvHoughLines2 function and two line equations.

Consumer Electronic Show - 2011

2011-01-05T18:11:00.000+01:00

The International Consumer Electronic Show (CES) is a major technology-related trade show held each January in the Las Vegas Convention Center, Las Vegas, Nevada. The 2011 CES will start with in almost 14 hours from January 6 to 9.

Camera Calibration - 3D Laser Scanner

2011-01-05T17:46:00.000+01:00

The first step is to find the camera Intrinsic and Extrinsic parameters. Intrinsic parameters are only depend on the camera and the Extrinsic parameters are the rotation and translation matrixes. For more details about the camera calibration parameters check the OpenCV Reference page. For the rest of this post I assume you already have installed and know how to compile an OpenCV program. (if not check this post)
So we need to find the Intrinsic matrix of camera, for this purpose I've used the cvCalibrateCamera2 function of OpenCV and then for Extrinsic matrix I've used the cvFindExtrinsicCameraParams2 function.
These are the standard functions of OpenCV for camera calibration. The cvCalibrateCamera2 function returns the Intrinsic parameters as a "3X3" Matrix which we call it Matrix: "A". The cvFindExtrinsicCameraParams2 returns the Extrinsic Parameters as to Vectors which we call them "Vr" for rotation and "Vt" for translation. as you can see from the prevues post picture our scene has two checker board on the left side and right side of our corner, So we need to calculate the Extrinsic parameters for both of them, one only with the left checker board and one only with right checker board.
This give us the rotation and translation from camera to the left coordinate and right coordinate of our scene.

And for Intrinsic parameter we can do it separately with one checker board. Since we need to calculate the 3D point cloud of our object we need these parameters to find the laser plane and intersect it with our object, and for finding the laser plane we need the equation of our laser line. Son in next post I am going to show you how to find the laser line equations from sequence of frames from a video.

3D Laser Scanner

2010-12-05T01:35:00.000+01:00

This is a very cool thing that I made in my course Lab. You only need an Object for scan, a corner shape scene, a digital camera and a laser which produce a laser line.
The whole process has 6 steps as follow:

1. Camera Calibration
2. Laser Line Detection
3. Object Detection
4. 3D Point Cloud
5. Color Point Cloud
6. Scan Registration with ICP

after these 6 steps you end up with a 3D point cloud of your object. This is really cool because you can have your own 3D laser scanner at a very low price at home.

In this picture you can see the corner scene our object and two checkerboards on both sides of the corner, those are needed for camera calibration, don't worry more will come about the camera calibration.

So I am going you to help you guys step by step to build this thing. There will be 6 posts on this topic one for each step and one at last to show some of my results. Just contact me if you have any questions.

Apple’s iOS

2010-11-23T01:15:00.001+01:00

Apple’s iOS 4.2 Available Today for iPad, iPhone, and iPod touch

Journey-Don't Stop Believin' (Arnel Pineda)

2010-11-10T23:53:00.000+01:00

Dire Straits - Sultans of Swing | NOT LIVE !!! | CD version !!! | Origin...

2010-11-10T23:46:00.000+01:00

Easy way to parse the HTML in Ruby

2010-10-27T21:51:00.000+02:00

There is an RubyGem available for parsing the HTML for ruby in a very fast manner that called Hpricot.
If you wonder what Gem is don't worry it is just a way for Ruby to call it's Packaged application or library, and each one has name and a version. For more information you can check the link or just google it.

Now you know what gem is and how to use them it is very easy to install the Hpricot just open a terminal and type:

gem install hpricot

you need to be a root user to install and it does, however, require a compiler to install (as it is written in C), so this should be ok on Linux and Mac OS X and afterward everything is ready to use.

Here is some demo to how to use it:

Lets have this HTML as our example.

<html>
  <body>
   <div id="container">
   <div id="navigation">
   <ul>
   <li><a href="/">Home</a></li>
   <li><a href="/contact></a></li>
   </ul>
   </div>
   <div id="sub-content">
   <p>This would be some sort of sidebar</p>
   </div>
   <div id="content">
   <p>This is paragraph 1</p>
   <p>This is paragraph 2</p>
   </div>
   </div>
   </body>
</html>

Let's assume the HTML is already in variable @html so we can easily pull out paragraphs by:

require 'hpricot'

doc = Hpricot(@html)

pars = Array.new

doc.search("div[@id=content]/p").each do |p|

pars << p.inner_html

end

Yes thats all you have to do ;) now you have an array with two elements that are the same as two P tags in content div. Notice that the P tag of sub-content isn't selected.
This is just a tip on Hpricot and the library is more powerful than this. For more information about this you can check the official page of Hpricot.

OpenCV on Mac OS X

2010-10-21T22:29:00.000+02:00

The easy way is to use MacPorts.
So I assume you have already installed MacPorts on your System.

In Snow Leopard you can build OpenCV 2.1.0 and above by MacPorts.
Step1: Update the MacPorts:

sudo port selfupdate

Step2: Build OpenCV:

sudo port install opencv

If you encounter problems just try installing dependencies with +universal whenever possible.

Step3: Let your shell know about the libraries and pkgconfig. For bash just:

export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

export LD_LIBRARY_PATH=/usr

Step4: Now you can compile OpenCV files with:

g++ -bind_at_load `pkg-config --cflags opencv` OpenCV-Sample.c -o OpenCV-Sample ` pkg-config --libs opencv`

Additional Step: If you don't like to type all of the above line every time you can make an alias and add it to you .profile file in your home directory if there is no .profile file in your home directory just create one. For that Just:

cd "to your home directory"

nano .profile

and add the following line in the file and save it:

alias gcv="g++ -bind_at_load `pkg-config --cflags opencv` `pkg-co nfig --libs opencv`"

Now just restart your Terminal and from now on you can compile the OpenCV files with the "gcv" command.

Back to The Mac

2010-10-21T20:56:00.000+02:00

The last event of Apple was on yesterday on Oct 20-2010. They basically introduce the new Mac OS X Lion, the new iLife 11 and the new Macbook Air which seems pretty cool.
It will be available in 11- and 13-inchmodels with 1.4- and 1.86-GHz Core 2 Duo processor. All the models have the Apple Flash storage which make the system much faster. A High Resolution Display with even thinner built in camera thats is great for making FaceTime calls. The new Display has even more pixel than todays Macbook Pro. The battery life gets up to 5 hour in 11-inch and 7 hour in 13-inch and up to incredible 30 days of standby time and all of these are just available from only 999$ from yesterday.
They are also a lots of new cool stuffs added to iPhoto 11 such as new templates for Slideshow and a gorgeous full screen mode that is great. They also make sending email much easer in iPhoto. You can just select the images you want and send them from iPhoto from your contact list automatically iPhoto does the attachment itself and also possible to use some templates for sending images.
Happy news for musicians they add really cool stuffs to GarageBand. They make sound mixing much easer and lots of other stuff.
OK, It is time for the new Mac OS X. In the Lion the OS X come together with iPad. The AppStore is going to be for Mac OS X too. The Mac App Store, one click downloads with automatic installation and automatic updates. It is the same as before and the developers gets 70% of the revenues. They add the autosave of iOs to OS X Lion. They added new multi-tuch gestures. They add the Lunch Pad which is the same thing as Home Screen in iPad it gives you a space for all of your applications.
They also add a Mission Control a new way for moving between your open applications and open documents it is a combination of expose and spaces and Dashboard and Full Screen apps. That you can switch between them by a gesture on your Touchpad and it looks really beautiful.
The Lion will be lunched this summer and the Mac AppStore will be available in 90 days.
Very excited about the new Stuffs.

Reference:
Apple Special Event
October 20, 2010

The first post of iPost

2010-10-21T17:23:00.000+02:00

Hi everybody,

This is y first post here and I am going to post as many as I can to keep this Blog updated.
Here I am going to post about everything from Music, Movies and Video Games to Computer Science stuff and new Technologies.

So staid tune for every thing new I will find.