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Hi,
Can any one tell me how the size of raw image computed?

say VGA - 640x480?

How may bytes will be one full frame?

how much will be the size of each pixel?

How many pixels constitutes one full line in the frame?

How different is it for foveon cameras?

How much bytes will each line of the frame contain and what will be
the
pixel size in foveon cameras and ordinary cameras

Regards,
Jm

John wrote:
> Hi,
> Can any one tell me how the size of raw image computed?
>
> say VGA - 640x480?
>
> How may bytes will be one full frame?

Typically:
12 bits x 640 x 480

> how much will be the size of each pixel?

12 bits, as it contains only one colour

> How many pixels constitutes one full line in the frame?
640, but they will be 320 R + 320 G, or 320 B + 320 G pixels

> How different is it for foveon cameras?
>
> How much bytes will each line of the frame contain and what will be
> the
> pixel size in foveon cameras and ordinary cameras
>
> Regards,
> Jm

I hope that helps somewhat. I don't know how many bits Foveon uses, but
it records an RGB value at each pixel - but it does not have as many
pixels as a Bayer camera.

Cheers,
David

>
> Typically:
> 12 bits x 640 x 480
>
Not all Raw is 12 bits.
Typically Raw is compressed.

Example for Nikon
Size of the raw is 3037 x 2012.
One day,
Smallest 4785KB
Largest 7106KB
Average 5408KB

Average is pretty stable. (Works out to 0.9 byte for each pixel).

Ben

ben brugman wrote:
>> Typically:
>> 12 bits x 640 x 480
>>
> Not all Raw is 12 bits.
> Typically Raw is compressed.
>
> Example for Nikon
> Size of the raw is 3037 x 2012.
> One day,
> Smallest 4785KB
> Largest 7106KB
> Average 5408KB
>
> Average is pretty stable. (Works out to 0.9 byte for each pixel).
>
> Ben

Thanks, Ben. I was trying to give a first-cut answer to demonstrate the
principles, so it's helpful to have your input as well. I know that Nikon
offers both lossless and lossy compression as well. What sort are you
using for the figures above?

Cheers,
David

In article <61s5k.10332$> , David J
Taylor <david->
wrote:

> > How different is it for foveon cameras?
> >
> > How much bytes will each line of the frame contain and what will be
> > the
> > pixel size in foveon cameras and ordinary cameras
> >
> I hope that helps somewhat. I don't know how many bits Foveon uses, but
> it records an RGB value at each pixel - but it does not have as many
> pixels as a Bayer camera.

sigma uses a12 bit a/d converter, then it goes through a funky lookup
table that scales the data and applies some sort of colour conversion,
and then it's lossy compressed (sigma calls it 'nearly lossless').

it's not exactly 'raw.'

nospam wrote:
[]
> sigma uses a12 bit a/d converter, then it goes through a funky lookup
> table that scales the data and applies some sort of colour conversion,
> and then it's lossy compressed (sigma calls it 'nearly lossless').
>
> it's not exactly 'raw.'

Half-baked?

David

In article <NaJ5k.10737$> , David J
Taylor <david->
wrote:

> > it's not exactly 'raw.'
>
> Half-baked?

the file format isn't the only thing about the sigma cameras can be
considered 'half-baked.'

In message
<85463b64-ad2c-4ad9-8d41->,
John <> writes
>Hi,
> Can any one tell me how the size of raw image computed?
>
> say VGA - 640x480?

Cameras that give RAW format(s) are generally a lot higher than VGA

> How may bytes will be one full frame?
Difficult there are several frame sizes used on "35mm" DSLRs and it
depends on the MP of the camera

http://en.wikipedia.org/wiki/RAW_image_format

http://www.tidalwave.it/infoglueDeli...?siteNodeId=18
6&languageId=1&contentId=-1#1.1

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\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

Why 12 bits? isnt it 36 bits for all the 3 colors?


Why only 2 colors in 640? i thought it should be 640/3 r, 640/3 g,
640/3 blue


The image is not raw probably its processed after goin through a a/d.


Regards,
jo


On Jun 16, 4:21 pm, "David J Taylor" <david-tay...@blueyonder.neither-
this-bit.nor-this-bit.co.uk> wrote:
> John wrote:
> > Hi,
> > Can any one tell me how the size of raw image computed?
>
> > say VGA - 640x480?
>
> > How may bytes will be one full frame?
>
> Typically:
> 12 bits x 640 x 480
>
> > how much will be the size of each pixel?
>
> 12 bits, as it contains only one colour
>
> > How many pixels constitutes one full line in the frame?
>
> 640, but they will be 320 R + 320 G, or 320 B + 320 G pixels
>
> > How different is it for foveon cameras?
>
> > How much bytes will each line of the frame contain and what will be
> > the
> > pixel size in foveon cameras and ordinary cameras
>
> > Regards,
> > Jm
>
> I hope that helps somewhat. I don't know how many bits Foveon uses, but
> it records an RGB value at each pixel - but it does not have as many
> pixels as a Bayer camera.
>
> Cheers,
> David

John wrote:
> Why 12 bits? isnt it 36 bits for all the 3 colors?

Each pixel senses only /one/ colour.
>
> Why only 2 colors in 640? i thought it should be 640/3 r, 640/3 g,
> 640/3 blue

The classic Bayer pattern has twice as many green as red or blue, to
improve resolution and snr.

> The image is not raw probably its processed after goin through a a/d.
>
>
> Regards,
> jo

That depends to which camera you are referring. Some process more than
others.

David