help-octave
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Creating picture X*Y pixel by pixel


From: Martin Weiser
Subject: Re: Creating picture X*Y pixel by pixel
Date: Mon, 09 Aug 2010 20:32:01 +0200
User-agent: Internet Messaging Program (IMP) H3 (4.3.7)

Cituji ZWD <address@hidden>:


Hello,

I want to create a picture e.g. 640x480 and want to be able to change the
color of each pixel.
So I want to create a picture pixel by pixel(and being able to say pixel on
235x198 has the color grey) and save it as a .jpg

Im a beginner in octave so any help would be great


Thanks
ZWD
--
View this message in context: http://octave.1599824.n4.nabble.com/Creating-picture-X-Y-pixel-by-pixel-tp2318402p2318402.html
Sent from the Octave - General mailing list archive at Nabble.com.
_______________________________________________
Help-octave mailing list
address@hidden
https://www-old.cae.wisc.edu/mailman/listinfo/help-octave


Hello.
In octave, images are just matrices. Colour images are just 3 matrices (one for red, one for green, one for blue) bundled together (superimposed) into an 3D array.
So, create your matrices, eg. like this:
# prepare them
red=zeros(2,2)
green=zeros(2,2)
blue=zeros(2,2)

#"colour" pixels in them (0-255)

#red  matrix
red(1,1)=100

#green
green(1,2)=150

#blue one
blue(2,2)=200

# bundle them together
fig=cat(3,red,green,blue)

# if you want to see that figure
image(fig)

# if you want to save it as jpeg
imwrite(fig, "some_image_name.jpg")

Simple, is not it?
If you need just a monochromatic (eg. white-gray-black) figure, you need just a single matrix instead of 3D array.

So, I hope this helps.
Martin








reply via email to

[Prev in Thread] Current Thread [Next in Thread]