Image to numeric array

[Dimitrios Charitatos]

Hello,

I suspect that there is a quite straight forward answer to this, but I can't
find it... I want to import an image and extract a matrix (or array) from it
with elements showing the RGB value of each pixel. But I want to be able to do
this with all types of image formats. It was suggested that a function such as
'B = numeric.from_im age(A)' was used but I can't find it in any of the
libraries. I was hoping you could help me on this.

Thank you,
Dimitris

[Diez B. Roggisch]

Re: Image to numeric array

Dimitrios Charitatos wrote:
[color=blue]
> Hello,
>
> I suspect that there is a quite straight forward answer to this, but I
> can't find it... I want to import an image and extract a matrix (or array)
> from it with elements showing the RGB value of each pixel. But I want to
> be able to do this with all types of image formats. It was suggested that
> a function such as 'B = numeric.from_im age(A)' was used but I can't find
> it in any of the libraries. I was hoping you could help me on this.[/color]

You have to install the numeric library for that. Googling numeric python
will bring you there pretty quick.

Diez

[Claudio Grondi]

Re: Image to numeric array

Diez B. Roggisch wrote:[color=blue]
> Dimitrios Charitatos wrote:
>
>[color=green]
>>Hello,
>>
>>I suspect that there is a quite straight forward answer to this, but I
>>can't find it... I want to import an image and extract a matrix (or array)
>>from it with elements showing the RGB value of each pixel. But I want to
>>be able to do this with all types of image formats. It was suggested that
>>a function such as 'B = numeric.from_im age(A)' was used but I can't find
>>it in any of the libraries. I was hoping you could help me on this.[/color]
>
>
> You have to install the numeric library for that. Googling numeric python
> will bring you there pretty quick.
>
> Diez[/color]
Is there a difference between the 'Numeric' and 'numeric' module?
I have on my system only Numeric... And this has no function like
'from_image'.

The usual way of doing such things is to use PIL (Python Image Library)
to load the image from file, then export it from PIL to a Python string
in order to import from this string to an array of the targeted
numerical module.

Really curious if there is a direct way in any of the numerical
packages, as it would save the time and effort of unnecessary
conversions from PIL, ImageMagick or from other image libraries.

Claudio

[Diez B. Roggisch]

Re: Image to numeric array

> Is there a difference between the 'Numeric' and 'numeric' module?[color=blue]
> I have on my system only Numeric... And this has no function like
> 'from_image'.[/color]

I actually didn't check that - I just wanted to point the OP to the
numeric-module(s) available, as he suggested that
[color=blue]
>The usual way of doing such things is to use PIL (Python Image Library)
>to load the image from file, then export it from PIL to a Python string
>in order to import from this string to an array of the targeted
>numerical module.[/color]

I'd go for the getdata() method instead.
[color=blue]
>Really curious if there is a direct way in any of the numerical
>packages, as it would save the time and effort of unnecessary
>conversions from PIL, ImageMagick or from other image libraries.[/color]

Whatever module is capable of converting needs to know how to read images -
either by itself, or by means of another module.


I know for sure that pygame supports retrieving pixel-data as array.

Diez

[Claudio Grondi]

Re: Image to numeric array

Diez B. Roggisch wrote:[color=blue][color=green]
>>Is there a difference between the 'Numeric' and 'numeric' module?
>>I have on my system only Numeric... And this has no function like
>>'from_image '.[/color]
>
>
> I actually didn't check that - I just wanted to point the OP to the
> numeric-module(s) available, as he suggested that
>
>[color=green]
>>The usual way of doing such things is to use PIL (Python Image Library)
>>to load the image from file, then export it from PIL to a Python string
>>in order to import from this string to an array of the targeted
>>numerical module.[/color]
>
>
> I'd go for the getdata() method instead.[/color]
Yes, you are right.
Sorry, I should have checked it in source code before posting just from
my memory. Usage of .tostring() was my first approach - I have replaced
it later by .getdata() because of speed issues (we are speaking here
about methods of the Image module available after installation of PIL).
As I have experience with numarray only, I can't help here directly with
a code example for Numeric.

Claudio[color=blue]
>
>[color=green]
>>Really curious if there is a direct way in any of the numerical
>>packages, as it would save the time and effort of unnecessary
>>conversions from PIL, ImageMagick or from other image libraries.[/color]
>
>
> Whatever module is capable of converting needs to know how to read images -
> either by itself, or by means of another module.
>
>
> I know for sure that pygame supports retrieving pixel-data as array.
>
> Diez[/color]