Prev: non-blocking calls to external APIs
Next: a question about gem's ~>
From: Pearce Pearce on 28 Mar 2010 12:02
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/.

From: Markus Schirp on 28 Mar 2010 13:56
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/.

From: Markus Schirp on 28 Mar 2010 14:01
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/.

 | 
Pages: 1
Prev: non-blocking calls to external APIs
Next: a question about gem's ~>