Monthly Archives: April 2015

What is the difference between multispectral and hyperspectral imagery?

Original source from: http://www.extension.org/pages/40073/what-is-the-difference-between-multispectral-and-hyperspectral-imagery#.VUGDZdOqpBc

Multispectral imagery is produced by sensors that measure reflected energy within several specific sections (also called bands) of the electromagnetic spectrum. Multispectral sensors usually have between 3 and 10 different band measurements in each pixel of the images they produce. Examples of bands in these sensors typically include visible green, visible red, near infrared, etc. Landsat, Quickbird, and Spot satellites are well-known satellite sensors that use multispectral sensors. Hyperspectral sensors measure energy in narrower and more numerous bands than multispectral sensors. Hyperspectral images can contain as many as 200 (or more) contiguous spectral bands. The numerous narrow bands of hyperspectral sensors provide a continuous spectral measurement across the entire electromagnetic spectrum and therefore are more sensitive to subtle variations in reflected energy. Images produced from hyperspectral sensors contain much more data than images from multispectral sensors and have a greater potential to detect differences among land and water features. For example, multispectral imagery can be used to map forested areas, while hyperspectral imagery can be used to map tree species within the forest.

 

MultispectralComparedToHyperspectralCourtesy: http://en.wikipedia.org/wiki/Hyperspectral_imaging

 

Showing hidden files in finder within MACOS

By default, showing hidden files in Finder is disabled. (e.g., file names start with ‘.’)

“.bash_profile” or “.vimrc” such configuration files are only available on terminal and some time it is tricky.

There is an workaround to enable the showing feature in Finder.

1. Open your terminal

2. just type the following

defaults write com.apple.finder AppleShowAllFiles YES

3. Relaunch your finder by choosing “relaunch”. This menu can be found from top left apple and select “Force Quit…” and choose “Finder”.

You will be able to see hidden files.

 

 

MATLAB 2014a Bug, BLAS loading error: dlopen: cannot load any more object with static TLS

This article is Just for future reference.

I faced a MATLAB bug: BLAS loading error: dlopen: cannot load any more object with static TLS.

My MATLAB version is 2014a running on Ubuntu 14.04.01

Here is the workaround and what you only need to do is

1. Download the attached file from the following link.

2. Replace libiomp5.so file at /R2014a/sys/os/glnxa64 (Ubuntu)

http://de.mathworks.com/support/bugreports/961964

Cheers,