Thanks.

I was looking in the file output section, so I didn't stumble across
hf_gray_16 in the global settings. I tried it and it seems to work; at least
I'm getting gray output. While I can tell the difference between color and
grayscale, I can't with my eyes determine the number of grayscale bits. So I
have a few additional questions.

1a. If I need only 10 bit grayscale (or any other number between 8 and 16),
will Bits_Per_Color=10 only allow 10 bits of grayscale info to be written
into the file, assuming Output_File_Type=N?

1b. If I use Output_File_Type=N, I'll get a PNG file which can accept up to
16 bits of grayscale info. If I use Output_File_Type=S, will I get a BMP
file with only 8 bits of grayscale info? (This will be helpful to me too in
some cases, as I've been generating 24 bit color images and converting them
to grayscale with a separate utility and maybe now I can generate the 8 bit
grayscale BMP files directly.)

2. I was not aware of ImageMagick. I will download it tonight and try it
out.

3. The reason I am using grayscale is because I need to generate some images
to test what a monochrome analog or digital camera will see in a piece of
machinery I'm working on, in order to test some computer vision algorithms.
This leads me to a question that's not directly POVRay related, but someone
out there may know. I see that hf_gray_16 causes POVRay to use the luminance
formula to convert the color image to gray. I understand the reason for the
.3, .59 and .11 parameters is because that matches the human eye's
sensitivity to the three primary colors of light. Will a monochrome camera,
as used in most equipment with machine vision, have a similar sensitivity?
To put it another way, will a color camera looking at a color scene and
having its image converted to grayscale with the luminance formula produce
the "exact" same image as a monochrome camera looking at that same color
scene?

4. What is the purpose of a height field image? Any example scenes available
on this news server that show its application?

Thanks again,

Bill



"PoD" <pod### [at] internodeonnet> wrote in message
news:pan### [at] internodeonnet...
> On Tue, 17 Dec 2002 10:26:40 +0800, Bill Brehm wrote:
>
> > 1. is there a way to make POVRay render the image directly to 16 bit
> > grayscale?
> > 2. can anyone recommend a program (preferably freeware or shareware, so
I
> > can try it first) that can read in 48 bit color or 16 bit grayscale PNG
> > files and convert them to a 16 bit grayscale TIFF file?
> >
>
> 1. Put 'hf_gray_16 on' in the global_settings section as per 6.11.4 in the
>   3.5 manual. This will cause POV-Ray to output a 16 bit greyscale file
>
> 2. I think that the latest version of ImageMagick is meant to do 16 bit
>   image conversions.  I haven't tried this yet though.
>
> Cheers,
>   PoD.
>

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