From: Markus Schirp <mbj@...>
Date: 2010-03-29T03:01:14+09:00
Subject: Re: divide BMP to YUV channels

Hola again,

Im reposting the pseudocode, since the first one leads to 
uninitialized local variable 'pixel', renamed it to 'pixel_in_image'

image = open_source_image

y_image = open_new_image
u_image = open_new_image
v_image = open_new_image

for pixel_in_image in image do
  y,u,v = calculate_yuv_for_pixel(pixel_in_image)
  write_to_image(y_image,y)
  write_to_image(u_image,u)
  write_to_image(v_image,v)
end

On Mon, Mar 29, 2010 at 02:56:18AM +0900, Markus Schirp wrote:
> Hello,
> 
> I dont think the ruby-ml, or the ruby-forums, are an exersise solving
> machine... 
> 
> But i can give you the following overall picture of your programm
> (more pseudocode than ruby)
> 
> ==== BEGIN
> 
> image = open_source_image
> 
> y_image = open_new_image
> u_image = open_new_image
> v_image = open_new_image
> 
> for pixel_in_image in image do
>   y,u,v = calculate_yuv_for_pixel(pixel)
>   write_to_image(y_image,y)
>   write_to_image(u_image,u)
>   write_to_image(v_image,v)
> end
> 
> ==== END
> 
> greetings,
> 
> Markus
> 
> On Mon, Mar 29, 2010 at 01:02:25AM +0900, Pearce Pearce wrote:
> > Hey guys!
> > I have an univercity exersise:
> > I'm trying to get YUV channels from BMP picture, and output it like 3
> > grey images.
> > I know the proportion:
> > RGB to YUV
> > Y  = (0.257 * R) + (0.504 * G) + (0.098 * B) + 16
> > V =  (0.439 * R) - (0.368 * G) - (0.071 * B) + 128
> > U = -(0.148 * R) - (0.291 * G) + (0.439 * B) + 128
> > 
> > But don't know how to get it works with Ruby.
> > 
> > Thanks in advance!
> > -- 
> > Posted via http://www.ruby-forum.com/.