computing the standard deviation of pixels above zero

Hi Kyle,

Between your toflt and total put the following:

... | toflt | rcalc -if -of -e '$1=$1;cond=1e-6-$1' | total -if ...

-Greg

···

From: [email protected]
Date: June 14, 2010 2:58:11 PM PDT

I have an HDR image that was generated by combining the original HDR with
an equally sized bitmap image to mask out an area within the image for
analysis. I have a script that enables the average luminance of the masked
area to be computed via (from the below script):

taskavg=`thpic -o $inp $tdir/$task.pic | toflt | total -if`

*I would like to compute the standard deviation of only the non-zero
pixels and am unsure how to do this.

the program "total" has a number of options to calculate the mean, max,
min, RMS,etc, but i need to filter out all of the zero'ed pixels before/as
I pass the pixel data to it.

Any suggestions would be appreciated. I have put a sample image (out.hdr)
as well as the script, mask, and orig image (example.hdr) in the following
directory online

https://gaia.lbl.gov/people/kskonis/share/TEMP/masks_lab/

best,

Kyle Konis

KjhjgthGyWWWWWwwwWwweeeererrRRrrrrrrrrrrrTttttYYyyYuuiiooplkm¥fffffggggGGfGFgfgfGfGfgfffgfGtgFGGGGxudgfnmxfN

···

----- Original Message -----
From: [email protected] <[email protected]>
To: Radiance general discussion <[email protected]>
Sent: Tue Jun 15 04:56:36 2010
Subject: Re: [Radiance-general] computing the standard deviation of pixels above zero

On Mon, Jun 14, 2010 at 10:58 PM, <[email protected]> wrote:

# -h -H do not print header or resolution string
# -pG print only the primary GREEN
# -df Output [binary 32-bit float values]
alias toflt 'pvalue -h -H -pG -df \!*'

You probably should add a "-o" option here, too, unless you always use
images fresh from rpict (no further pfilt treatment).

Regards,
Thomas

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Ahh, seems Kristopher's kitty found a nice, warm laptop to sleep on...

···

From: "Baker, Kristopher" <[email protected]>
Date: June 15, 2010 4:40:23 PM PDT

KjhjgthGyWWWWWwwwWwweeeererrRRrrrrrrrrrrrTttttYYyyYuuiiooplkm¥fffffggggGGfGFgfgfGfGfgfffgfGtgFGGGGxudgfnmxfN

----- Original Message -----
From: [email protected] <[email protected]>
To: Radiance general discussion <[email protected]>

On Mon, Jun 14, 2010 at 10:58 PM, <[email protected]> wrote:

# -h -H do not print header or resolution string
# -pG print only the primary GREEN
# -df Output [binary 32-bit float values]
alias toflt 'pvalue -h -H -pG -df \!*'

You probably should add a "-o" option here, too, unless you always use
images fresh from rpict (no further pfilt treatment).

Regards,
Thomas

LOL!

···

________________________________________
From: [email protected] [[email protected]] On Behalf Of Greg Ward [[email protected]]
Sent: Tuesday, June 15, 2010 6:13 PM
To: Radiance general discussion
Subject: Re: [Radiance-general] computing the standard deviation of pixels above zero

Ahh, seems Kristopher's kitty found a nice, warm laptop to sleep on...

From: "Baker, Kristopher" <[email protected]>
Date: June 15, 2010 4:40:23 PM PDT

KjhjgthGyWWWWWwwwWwweeeererrRRrrrrrrrrrrrTttttYYyyYuuiiooplkm
¥fffffggggGGfGFgfgfGfGfgfffgfGtgFGGGGxudgfnmxfN

----- Original Message -----
From: [email protected] <[email protected]
>
To: Radiance general discussion <[email protected]>

On Mon, Jun 14, 2010 at 10:58 PM, <[email protected]> wrote:

# -h -H do not print header or resolution string
# -pG print only the primary GREEN
# -df Output [binary 32-bit float values]
alias toflt 'pvalue -h -H -pG -df \!*'

You probably should add a "-o" option here, too, unless you always use
images fresh from rpict (no further pfilt treatment).

Regards,
Thomas

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Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general