Grayscale to RGB conversion

[sharmistha paul]

I have 8 bit grayscale image. I'd like to convert this image into
Hi,

I have 8 bit grayscale image. I'd like to convert this image into RGB color. How I can do that?
I have Image J 1.37t.
Please help me.

Thank you.

Sharmistha


 
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[dscho]

Hi,

On Wed, 6 Dec 2006, sharmistha paul wrote:

> I have 8 bit grayscale image. I'd like to convert this image into RGB
> color. How I can do that?

In general, this is not possible, since there are _many_ colours having
the _same_ gray value when converting to grayscale. So which one to pick
when trying to convert back?

However, there has been some articles about that problem, which Gabriel
mentioned on the ImageJ Documentation Wiki IIRC, but no work has been done
to make this an ImageJ plugin as far as I know.

Ciao,
Dscho

[sharmistha paul]

Thanks.
I did as you said.
It's transform the image f
Hi Claude,

Thanks.
I did as you said.
It's transform the image from grayscale to RGB color. But it shows black and white image. I really need  the command for transforming the color image from my black and white (gray scale) picture.

I hope somebody help me to overcome the problem.

Sharmistha


----- Original Message ----
From: Claude Bonnard <[hidden email]>
To: sharmistha paul <[hidden email]>
Sent: Wednesday, December 6, 2006 11:25:41 AM
Subject: Re: Grayscale to RGB conversion


Hello Paul,

The simplestshould be  to go to  Image>color>RGB Merge and to use the same
image for every color! You will of course triple the size of your image , and
you need a 8 bit image to start with

Hope it helps
Regards,
Claude

--
Claude Bonnard Ph.D.
ISREC (Swiss Institute for Experimental Cancer Research)
Microscopy, Imaging and Morphology Core Facility [MIM]
Lab F216
Ch des Boveresses 155
CH-1066 Epalinges
Switzerland
email: [hidden email]
phone: [41-21]-692-5891
  fax: [41-21]-652-6933


 
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[P Nguyen]

You can converse 8 bit grayscale image to RGB color by Image > Type >
RGB color.

-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
sharmistha paul
Sent: Wednesday, December 06, 2006 5:46 AM
To: [hidden email]
Subject: Grayscale to RGB conversion

I have 8 bit grayscale image. I'd like to convert this image into Hi,

I have 8 bit grayscale image. I'd like to convert this image into RGB
color. How I can do that?
I have Image J 1.37t.
Please help me.

Thank you.

Sharmistha


 
________________________________________________________________________
____________
Yahoo! Music Unlimited
Access over 1 million songs.
http://music.yahoo.com/unlimited

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The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to [hidden email] - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.

[Gareth Edwards-3]

You could also apply a LUT of your selected colourscheme before converting the greyscale to RGB
colour.


************************************************
http://www.garethedwards.fotopic.net

Dr Gareth O Edwards
Cardiff School of Biosciences
Cardiff University
Main Building
Park Place
Cardiff CF10 3TL
Wales UK

Email: [hidden email]
Phone: [phone] (main)
Phone: [phone] (office/lab)

>>> "Nguyen, Phuc" <[hidden email]> 12/06/06 1:20 pm >>>
You can converse 8 bit grayscale image to RGB color by Image > Type >
RGB color.

-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
sharmistha paul
Sent: Wednesday, December 06, 2006 5:46 AM
To: [hidden email]
Subject: Grayscale to RGB conversion

I have 8 bit grayscale image. I'd like to convert this image into Hi,

I have 8 bit grayscale image. I'd like to convert this image into RGB
color. How I can do that?
I have Image J 1.37t.
Please help me.

Thank you.

Sharmistha


 
________________________________________________________________________
____________
Yahoo! Music Unlimited
Access over 1 million songs.
http://music.yahoo.com/unlimited 

****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review,
retransmission, dissemination, or other use of this information by persons or entities other than
the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic
Corporation immediately - by replying to this message or by sending an email to
[hidden email] - and destroy all copies of this information, including any
attachments, without reading or disclosing them.

Thank you.

[Michael Miller]

Hi,

What people are trying to say is, you can't do this unless you add more
information. You can't just run an operation and get the color back.

RGB stands for Red-Green-Blue, each channel is 8 bits. RGB is 24 bit color.

Greyscale is one 8 bit channel of intensity.

When you go RGB -> Greyscale you lose 1/3 of the information of the image.
Algorithms decide based on the different intensities of the red, green, and
blue channels what color to make each pixel. I'm sure there are several
papers and open source algorithms on this subject.

Going from Greyscale to RGB and getting color back, there's too much
nullspace. You need to introduce more information into the image, because
you've lost so much already. From a purely 8bit to 24bit perspective, there
are literally 2^16 more possibilities for each pixel; although I imagine
that number is sharply reduced because the available intensities have to
also satisfy whatever the algorithm chose RGB->Greyscale (as you are forming
a bijection at this point).

As others have already stated, no known algorithm exists in ImageJ at this
time.

One way that you can introduce more info, edit the LUT. You can experiment
with that in the Image -> Color menu. I believe you can use it to assign
each greyscale value as an index to a 24 bit color, allowing you to select
up to a maximum of 256 different colors for your greyscale image.

Good luck,
-Mike

----- Original Message -----
From: "sharmistha paul" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, December 06, 2006 7:16 AM
Subject: Re: Grayscale to RGB conversion


Thanks.
I did as you said.
It's transform the image f
Hi Claude,

Thanks.
I did as you said.
It's transform the image from grayscale to RGB color. But it shows black and
white image. I really need  the command for transforming the color image
from my black and white (gray scale) picture.

I hope somebody help me to overcome the problem.

Sharmistha


----- Original Message ----
From: Claude Bonnard <[hidden email]>
To: sharmistha paul <[hidden email]>
Sent: Wednesday, December 6, 2006 11:25:41 AM
Subject: Re: Grayscale to RGB conversion


Hello Paul,

The simplestshould be  to go to  Image>color>RGB Merge and to use the same
image for every color! You will of course triple the size of your image ,
and
you need a 8 bit image to start with

Hope it helps
Regards,
Claude

--
Claude Bonnard Ph.D.
ISREC (Swiss Institute for Experimental Cancer Research)
Microscopy, Imaging and Morphology Core Facility [MIM]
Lab F216
Ch des Boveresses 155
CH-1066 Epalinges
Switzerland
email: [hidden email]
phone: [41-21]-692-5891
  fax: [41-21]-652-6933



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