Saturday, July 30, 2011

Create a photo collage using a single command-line

In order to create a contact-sheet or a collage of many files under linux, I prefer to use a single command-line. I create a directory with all the images and use ImageMagick montage function:
montage -font Arial-Narrow -pointsize 10 -label '%t' -resize 100x150 *.jpg -geometry +3+3 -tile 4x4 -shadow collage.jpg

Thursday, July 28, 2011

HowTo use a computer without a screen attached

The Problem:
I have a Linux machine (Fedora 14)  with no screen attached. I view the graphics via VNC server. I had to adjust the system to use the Nvidia driver and tweak it for no screen.

The solution:
First we need to install the Nvidia driver. Then, we need to adjust the X configuration for no screen and our preferred resolution.

for more details see: http://forums.fedoraforum.org/showthread.php?t=204752

1. Update the kernel:

su
yum update kernel*
reboot


2. Add rpmfusion to your repository.

su
rpm -Uvh  http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm   http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

3. Depending on your card add nvidia akmod to the kernel and the proper driver. for a Gforce 9500GT on my 64bit machine:
yum install akmod-nvidia-260.19.36-1.fc14.x86_64 xorg-x11-drv-nvidia-libs-260.19.36-1.fc14.x86_64

4. Edit the xorg.conf file. don't forget to  adjust the Nvidia card for no screen attached by adding:
 Option "ConnectedMonitor" "CRT"
to the device section and adjust the screen resolution under the Screen section:

Section "Device"
    Identifier     "Card0"
    Driver         "nvidia"
	Option "ConnectedMonitor" "CRT"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Card0"
    Monitor        "Monitor0"
    SubSection     "Display"
        Viewport    0 0
        Modes      "1280x1024"
    EndSubSection
EndSection

Thursday, July 14, 2011

Daichi - ALOS : finding Images and Baseline Calculation

Using JAXA satellite "DAICHI" (ALOS) for SAR Interferometry might raise the need for calculating perpendicular baselines. One can use AUIG site to locate the needed images for interferometry and use PALSAR baseline calculator CalcBP for calculating perpendicular baselines. more info is available here.