How to get extreme values from a falsecolor image

Vaib · February 5, 2014, 5:24pm

Thank you Rob.

Am I doing it wrong? -a option is a "bad option" Not valid argument I
mean..
$ falsecolor -i foo.hdr -s 1000 -n 10 -l Lux -a > bar.hdr

And pextrem doesn't take HDR file. I have to work with HDR, as it has
conversion libraries in Java.

Vaib

···

On 5 February 2014 17:50, Guglielmetti, Robert <[email protected] > wrote:

Hi Vaib,

A couple of things:

Thing One: there is an -a option, which "autoscales" the max value for the
scale to peak at the max value found in the image.

Thing Two: yes, you can use pextrem to get the min and max values (in
Rr,Rg,Rb) printed to the command line.

- Rob

*From:* Vaib [mailto:[email protected]]
*Sent:* Wednesday, February 05, 2014 9:39 AM
*To:* Radiance general discussion
*Subject:* [Radiance-general] How to get extreme values from a falsecolor
image

Hello everyone,

Falsecolor's documentation states that "The *-e* option causes extrema
points to be printed on the brightest and darkest pixels of the input
picture."

Is there any way to output (not print on image) the extrema values? This
could be helpful in appropriately scaling the "scale".

Thank you!

Best regards,

Vaib

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Axel_Jacobs2 · February 5, 2014, 5:37pm

Vaib,

it's
'-s a', not '-a'
the following work, too:
'-s auto' and '-s Auto' (anything that starts with uppercase or lowercase 'a')

Regards

Axel

···

On 5 February 2014 17:24, Vaib <[email protected]> wrote:

Thank you Rob.

Am I doing it wrong? -a option is a "bad option" Not valid argument I
mean..
$ falsecolor -i foo.hdr -s 1000 -n 10 -l Lux -a > bar.hdr

And pextrem doesn't take HDR file. I have to work with HDR, as it has
conversion libraries in Java.

Vaib

On 5 February 2014 17:50, Guglielmetti, Robert > <[email protected]> wrote:

Hi Vaib,

A couple of things:

Thing One: there is an -a option, which "autoscales" the max value for the
scale to peak at the max value found in the image.

Thing Two: yes, you can use pextrem to get the min and max values (in
Rr,Rg,Rb) printed to the command line.

- Rob

From: Vaib [mailto:[email protected]]
Sent: Wednesday, February 05, 2014 9:39 AM
To: Radiance general discussion
Subject: [Radiance-general] How to get extreme values from a falsecolor
image

Hello everyone,

Falsecolor's documentation states that "The -e option causes extrema
points to be printed on the brightest and darkest pixels of the input
picture."

Is there any way to output (not print on image) the extrema values? This
could be helpful in appropriately scaling the "scale".

Thank you!

Best regards,

Vaib

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

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

Vaib · February 5, 2014, 5:48pm

Thank you!

I feel terrible, I should have been cautious (I need sleep).. My HDR was
currupt, as I stopped my Java procedures in the middle... I am sorry..

Yes, pextrem works fine.. Thank you Dr.Jacob for -s -a.

Vaib

···

On 5 February 2014 18:38, Guglielmetti, Robert <[email protected] > wrote:

Shit, it appears that the -a option fell off the wagon when falsecolor was
converted from a csh script to a Perl script. I swear it used to be there.
Am I losing my mind? This is entirely possible. OK, ok, bad info there.
Sorry about that one, Vaib.

Now then, the pextrem deal. What do you mean it doesn't take an hdr file?
That's precisely what it does. Here's what that should look like:

$ pextrem pass2-v2lux.hdr

99 511 0.000000e+00 0.000000e+00 0.000000e+00

4 232 9.960938e-01 9.960938e-01 9.960938e-01

IOW, you call pextrem, give it an hdr image, and it returns the pixel
coordinates (x,y) and radiance (Rr,Rg,Rb) of the low and high pixels.
What's happening when you try this?

*From:* Vaib [mailto:[email protected]]
*Sent:* Wednesday, February 05, 2014 10:25 AM
*To:* Radiance general discussion
*Subject:* Re: [Radiance-general] How to get extreme values from a
falsecolor image

Thank you Rob.

Am I doing it wrong? -a option is a "bad option" Not valid argument I
mean..

$ falsecolor -i foo.hdr -s 1000 -n 10 -l Lux -a > bar.hdr

And pextrem doesn't take HDR file. I have to work with HDR, as it has
conversion libraries in Java.

Vaib

On 5 February 2014 17:50, Guglielmetti, Robert < > [email protected]> wrote:

Hi Vaib,

A couple of things:

Thing One: there is an -a option, which "autoscales" the max value for the
scale to peak at the max value found in the image.

Thing Two: yes, you can use pextrem to get the min and max values (in
Rr,Rg,Rb) printed to the command line.

- Rob

*From:* Vaib [mailto:[email protected]]
*Sent:* Wednesday, February 05, 2014 9:39 AM
*To:* Radiance general discussion
*Subject:* [Radiance-general] How to get extreme values from a falsecolor
image

Hello everyone,

Falsecolor's documentation states that "The *-e* option causes extrema
points to be printed on the brightest and darkest pixels of the input
picture."

Is there any way to output (not print on image) the extrema values? This
could be helpful in appropriately scaling the "scale".

Thank you!

Best regards,

Vaib

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

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