Re:

[Peter Sisak]

The luminosity-weighed formula (assuming 0-255 ranges for r,g,b components 
and x output) is, as specified in BT.601 recommendation:

x = 0.299r + 0.587g + 0.114b

Such as for the (100,0,150) triplet that's x = 0.299*100+0.587*0+0.114*150, 
works out to 47. So it should be (47,47,47) grayscale.

Regards
Péter Sisák

----- Eredeti üzenet ----- 
From: John Guin
Sent: Wednesday, April 23, 2014 6:03 PM
To: 'Laurent Hoeltgen' ; address@hidden
Subject: RE:

(resending - got bounced last time)

-----Original Message-----
From: John Guin [mailto:address@hidden
Sent: Wednesday, April 23, 2014 8:50 AM
To: 'Laurent Hoeltgen'; address@hidden
Subject: RE:

Is there a reason you would not use rgb2gray ?

Help rgbgray


John


-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of
Laurent Hoeltgen
Sent: Wednesday, April 23, 2014 1:03 AM
To: address@hidden
Subject: Re:

On 23/04/14 09:34, Dincy Paul wrote:
> Hi..
> How to convert an RGB image into a gray scale image . Please help.
> Regards
> Dincy
>
>
> _______________________________________________
> Help-octave mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/help-octave

Hi,

a naive way is to do a simple (weighted) average of the three RGB channels.

Regards,
Laurent

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