News: Tips and tricks: recursive show images

The "Mastering OpenCV with Practical Computer Vision Projects" book is done and published!
Also: including a screenshot of each project...
This will be the main issue.
... to see the screenshot from each project
...and also to find a way for any file to use
Let's take the book and source code:

$ git clone git://github.com/MasteringOpenCV/code.git

Go to the main folder: $ cd code and use this:

code]$ ls 
Chapter1_AndroidCartoonifier     Chapter7_HeadPoseEstimation
Chapter2_iPhoneAR                Chapter8_FaceRecognition
Chapter3_MarkerlessAR            Chapter9_FluidInteractionUsingKinect
Chapter4_StructureFromMotion     LICENSE.txt
Chapter5_NumberPlateRecognition  README.md
Chapter6_NonRigidFaceTracking

If we use the tree Linux command the result will be:

.
|-- Chapter1_AndroidCartoonifier
|   |-- Cartoonifier_Android
|   |   |-- AndroidManifest.xml
|   |   |-- jni
|   |   |   |-- Android.mk
|   |   |   |-- Application.mk
|   |   |   `-- jni_part.cpp
|   |   |-- project.properties
|   |   |-- res
|   |   |   |-- drawable
|   |   |   |   `-- icon.png
|   |   |   `-- values
|   |   |       `-- strings.xml
|   |   `-- src
|   |       `-- com
|   |           `-- Cartoonifier
|   |               |-- CartoonifierApp.java
|   |               |-- CartoonifierView.java
|   |               `-- CartoonifierViewBase.java
|   |-- Cartoonifier_Desktop
|   |   |-- CMakeLists.txt
|   |   |-- ImageUtils.h
|   |   |-- ImageUtils_0.7.cpp
|   |   |-- cartoon.cpp
|   |   |-- cartoon.h
|   |   `-- main_desktop.cpp
|   |-- README.txt
|   `-- screenshot.png
|-- Chapter2_iPhoneAR

We need something to find the absolute path and give that to gthumb to run it.
First, find the screenshot:

 code]$ ls -d  $PWD/**/*.png
/home/free-tutorials/code/Chapter1_AndroidCartoonifier/screenshot.png
/home/free-tutorials/code/Chapter2_iPhoneAR/screenshot.png
/home/free-tutorials/code/Chapter3_MarkerlessAR/screenshot.png
/home/free-tutorials/code/Chapter4_StructureFromMotion/screenshot.png
/home/free-tutorials/code/Chapter5_NumberPlateRecognition/screenshot.png
/home/free-tutorials/code/Chapter6_NonRigidFaceTracking/screenshot.png
/home/free-tutorials/code/Chapter7_HeadPoseEstimation/screenshot.png
/home/free-tutorials/code/Chapter8_FaceRecognition/screenshot.png
/home/free-tutorials/code/Chapter9_FluidInteractionUsingKinect/screenshot.png

Now will run gthumb with all these images:

code]$ ls -d  $PWD/**/*.png | xargs gthumb 

Linus Torvalds - kernel 3.7 is now out.

From: Linus Torvalds <torvalds <at> linux-foundation.org>

Subject: Linux 3.7

Newsgroups: gmane.linux.kernel

Date: 2012-12-11 03:59:50 GMT (9 hours and 45 minutes ago)

Whee. After an extra rc release, 3.7 is now out. After a few more trials at fixing things, in the end we ended up reverting the kswapd changes that caused problems. And with the extra rc, I had decided to risk doing the buffer.c cleanups that would otherwise have just been marked for stable during the next merge window, and had enough time to fix a few problems that people found there too. There's also a fix for a SCSI driver bug that was exposed by the last-minute workqueue fixes in rc8. Other than that, there's a few networking fixes, and some trivial fixes for sparc and MIPS. Anyway, it's been a somewhat drawn out release despite the 3.7 merge window having otherwise appeared pretty straightforward, and none of the rc's were all that big either. But we're done, and this means that the merge window will close on Christmas eve. Or rather, I'll probably close it a couple of days early. For obvious reasons. It's the main commercial holiday of the year, after all. So aim for winter solstice, and no later. Deal? And even then, I might be deep into the glögg. Linus

Read more here.

News: Unusual commands in linux : pv

Today I will speak about pv command.
Pipe viewer - pv is a terminal-based tool for monitoring the progress of data through a pipeline written by Andrew Wood
To install pv on Fedora or CentOS do this:

$ sudo yum install pv

You can read the man file to get more help:

man pv

The result is:

NAME
       pv - monitor the progress of data through a pipe

SYNOPSIS
       pv [OPTION] [FILE]...
       pv [-h|-V]

DESCRIPTION
       pv  allows  a  user  to see the progress of data through a pipeline, by
       giving information such as time  elapsed,  percentage  completed  (with
       progress  bar),  current  throughput  rate, total data transferred, and
       ETA.

       To use it, insert it in a pipeline  between  two  processes,  with  the
       appropriate  options.  Its standard input will be passed through to its
       standard output and progress will be shown on standard error.

Let's see some examples.
You can get precise time how long it will take.

$ pv voronoi.py | python 
 737B 0:00:00 [86.9kB/s] [==================================>] 100%

You can see how fast the computer reads from /dev/zero.

$ pv /dev/zero > /dev/null
1.1GB 0:00:05 [   2GB/s] [    <=>                                            ]

You can use the dialog to show a progress bar.
To do this you need to use -n arg.

$ (pv -n /dev/zero > /dev/null) 2>&1 | dialog --gauge "Please wait" 10 70 0

News: Tips and tricks: watch and cat.

Sometimes it is necessary to find solutions.
Today's example involves two Linux commands:
watch and cat
Here is a simple method by creating a script that returns an output:

while [ 1 ]; do cat /proc/meminfo; date; echo; sleep 1; done

Make this script executable and name it: meminfo.
The output is then processed by the command:

$ watch -d ./meminfo 

This simple method can be applied to other files ...

Using SL4A bash shell script to connect Linux with Android tablet .

Using Linux with Android OS is very simple.
I install the next two android application: sl4a_r6.apk and PythonForAndroid-r7b1.apk.
Use the PythonForAndroid-r7b1.apk just if you want to write some python scripts.
We can download it from here.
The first: sl4a_r6 it's used to write and run scripts like bash shell, HTML, Java, Python.
With this, the SL4A provides and make APIs available via JSON RPC calls.
The PythonForAndroid-r7b1 allow you to install python modules...
We can read more on this website.
Let's start with one simple bash shell script.
We will make a shell script to test the connection between Linux and Android tablet.
The connection will be through a wireless router that has opened the port through which the communication.
Tablet has Android 4.0.
We use the Linux command NC, see: nc command.
This is the script on the tablet and it will run first.

nc -l -p 7000

See the next image:

Button 1 - run the script
Button 2 - edit the script
Button 3 - save the script
Button 4 - remove the script
Use the next command with your IP on the Linux terminal.

nc xxx.xxx.xxx.xxx 7000

If you type something in your terminal you will see on a tablet.
The input from my linux terminal can be seen in the next image:

Ant this is the output on my tablet.

We can test multiple features of command nc.
I'm just curious if you have some new ideas on this subject.