[Radiance-general] Removing black areas in imagemapping

[Per Haugaard]

Hi Thomas,

I tested the nonzero part of your mail. nonzero(r,g,b) = 1; returns the falsecolor image on the workingplane and nonzero(r,g,b) = 0; returns the image 3 on http://perhaugaard.blogspot.com/. 

The error is elsewhere or?


/Per



--- Den tirs 12/1/10 skrev Thomas Bleicher <tbleicher at googlemail.com>:

Fra: Thomas Bleicher <tbleicher at googlemail.com>
Emne: Re: [Radiance-general] Removing black areas in imagemapping
Til: perhaugaard at yahoo.dk, "Radiance general discussion" <radiance-general at radiance-online.org>
Dato: tirsdag 12. januar 2010 11.55

Per.

I still think that your problem is the value at which
mixfunc decides if the value from the fc image should
be used or not (based on your non-zero function).

You can try and replace the function once with


nonzero(r,g,b) = 1

and then with 

nonzero(r,g,b) = 0

In the first case you should get the whole surface
in black (because every pixel is used), in the second
you should see nothing at all. (Mind you, I haven't

tested these functions; I only assume they work!)

Also use phisto on your falsecolor image to see the
actual values of the black pixels. It looks like there
is a range of "dark grey" instead of black. If you convert

your image to tiff or ppm, edit the grey values to black
in Photoshop and convert it back you might have a
better result already. I'm sure there is also a way to
do this with Radiance tools but I don't have one ready.


On Tue, Jan 12, 2010 at 9:09 AM, Per Haugaard <perhaugaard at yahoo.dk> wrote:


I have not been working with HDR images. Maybe you can update on how to easily convert from pic-files to hdr-files in Linux, so I can upload these for illustration
 purposes.


*.pic files are *.hdr images. The extension is just a
convention and since the world has adopted *.hdr for
this type of images the Radiance community is moving

to this extension, too.

Regards,
Thomas





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