Re: newbie question

[David Grundberg]

Richard Evans wrote:
> Hi,
>  
> I'm new to Octave, but managed to get it successfully installed and 
> tested it successfully on some plots and small matrix manipulations.
>  
> I'd like to use 16 bit tif or txt images as matrices and manipulate 
> them in Octave.  I'm not sure how to load an image as a matrix in 
> Octave and assign it to a letter name for manipulation.
>  
> I've ordered John Eaton's book but it won't arrive for a while.... 
> thought I'd ask here so I could get started.  I've looked at the html 
> version of the book on the web, but it doesn't seem to directly answer 
> the question.
>  
> Rick
>  
>  

Rick,

To load 16-bit tiff images you need Octave/graphicsmagick compiled with 
16-bit support (quantumdepth set to 16). If not, the 16-bit image is 
converted to 8-bit on load.

Use

a = imread ("myfile.tif");

to assign image data as a matrix to variable a.


To see the class of the matrix, write

class (a)


Txt-files can be loaded too, using other functions, depending on format. 
dlmread, csvread, etcetera.

hth,
David