PacktPub: Buy One, Get One Free #Packt2k

Viernes, 21 de marzo de 2014 24 comentarios


At Packt Publishing are launching an exciting campaign to coincide with the release of our 2000th title. During this offer Packt is giving its reader a chance to dive into their comprehensive catalog and Buy One, Get One Free across their entire range of eBooks.

The campaign begins on 18th-Mar-2014 and will continue until 26th-Mar-2014. Following are the benefits readers can avail during this campaign.

  • Unlimited purchases during the offer period
  • Offer is automatically applied at checkout

Buy One, Get One Free on all of #Packt’s 2000 eBooks! #Packt2k

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Acquiring the Logitech C920′s H264 stream using gstreamer

Sábado, 26 de octubre de 2013 12 comentarios

Webcam Logitech C920

Recently some web-cameras including onboard HD video encoding have appeared in the market. One of these cameras is the Logitech C920, and I had the opportunity to play with it at work. This camera is able to produce a 1080p H264-encoded stream at 30 fps, but I wasn’t able to access properly to it the first time I deal with this issue in Ubuntu 12.04 more than one year ago. At those moments, the camera was so novel that even v4l2 didn’t include support for H264 pixel format. Luckily, at the publishing date of this post, some alternatives can be used for accessing successfully to the compressed stream. In this post I will explain how to do it with the latest versions of gstreamer. Leer más…

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PacktPub discount sales

Lunes, 14 de octubre de 2013 69 comentarios


To mark Columbus Day, Packt is giving everyone the chance to explore its entire catalogue of eBooks and videos at 50% off in its biggest ever sale. During the event, anyone will be able to use the discount code #COL50 at checkout for any eBooks or videos of their choice – as many times as they like until Thursday October 17th.

I’ve been a reviewer of some of the OpenCV books and video courses in this editorial, and they have some very interesting books for developers. Take a look!


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GReplace – Replace a pattern across multiple files in Vim

Martes, 13 de agosto de 2013 10 comentarios


In our beloved editor we have the powerful substitute command to Find and replace text in the current buffer. The options are almost unlimited but if we want to apply the changes to multiple files the best option we have is to use the greplace plugin. These are the steps you should follow for replacing chunk of text in several files:

  1. :Gsearch stringA * -R (* -R means for all the files in a recursive way). It will appear a new buffer window with the results
  2. :%s/stringA/stringB/g Replace text in the new buffer with (you can do it easily with the substitute command). 
  3. :Greplace . It will open all the necessary files and perform the change indicated before. You should confirm each change or press ‘a’ in order to apply the changes to all the files.
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OpenCV Computer Vision with Python [The Review]

Domingo, 23 de junio de 2013 84 comentarios

OpenCV with Python

If you have some experience with the Python programming language and your aim is start to use the OpenCV library for creating computer vision / image processing applications, this book is certainly a good start point.

The author focus the first chapter into explaining the several installation options that exists for the different platforms (Win, Mac, Linux). This is good since such a huge library has several ways to be installed, with the possibility of enabling/disabling some features. I can remember how I spent much time dealing with these kind of issues in my first contact with OpenCV some years ago.

In the rest of the chapters some of the basic key issues of the library are introduced to the readers in order to create a simple application which involves:

  • Input / output features of the library (Dealing with images, videos, devices, etc.).
  • Basic filtering and color-space conversions.
  • Face tracking with Haar cascades classifiers.
  • Depth information manipulation (depth sensors such as kinect).

All the code is designed using the Object oriented paradigm in order to be extensible and reusable. This is one of the things I more liked about this book, since many of the python examples (as well as C/C++ ones) provided by the OpenCV library are programmed like independent programs/scripts that could not be extensible.

The only negative point I can found in this book is its short content. I miss the explanation of some basic features/algorithms I use to employ daily when I’m working with OpenCV (in C++), but since the book is meant for beginners I can understand it.

It is important to note that this book assumes you have basic knowledge about Python programming.

Overall, I would give a 3.5/5.0 to this book.

You can buy it in this link:

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