Request for hdrgen's updated version for Linux 64-bit system

Hi Sneha,

Glad that worked for you. I'll include it in the package on my website for future downloaders.

The -s factor doesn't have to be exact. It just has to have the correct relative relation between captures. If you capture your images in the usual 1-EV separation, you might use for example:

img1.jpg 1/60th second
img2.jpg 1/125th second
img3.jpg 1/250th second

hdrgen -s 1 img1.jpg -s 2.0 img2.jpg -s 4.0 img3.jpg

In other words, you want the pixels times the multipliers to roughly equal each other (within the limits of exposure range). If you happen to know what the absolute level of some image is, you can use that. Here is an approximate formula for the -s factor based on ISO, f-stop, and exposure time:

  s2nits = 87*f_stop^2/(exp_time*ISO)

Cheers,
-Greg

···

From: Sneha Jain <sneha.jain@research.iiit.ac.in>
Date: July 13, 2017 5:36:55 AM PDT

Hi Greg,

Thank you so much for providing this version. I am glad to inform you that this version is working with Linux 64-bit. Though I am struggling to understand the -s stonits factor for each LDR image that I need to specify for getting an HDR image. I am connected to a fish-eye lens all-sky camera and unable to get this factor automatically. If you could suggest me on how to get this; it would be really great.

Thank you.

Regards,

Sneha Jain
On Wed, Jul 12, 2017 at 7:40 PM, Gregory J. Ward <gregoryjward@gmail.com> wrote:
Hi Sneha,

Try this version and tell me if it's any better. Building under Linux is painful because of the required libraries (OpenEXR in particular).

Cheers,
-Greg

P.S. I "cleared" your post to the HDRI mailing list, but you need to subscribe to the list using the address you post with in order for this to be unnecessary.

From: Sneha Jain <sneha.jain@research.iiit.ac.in>
Subject: Request for hdrgen's updated version for Linux 64-bit system
Date: July 12, 2017 3:34:08 AM PDT
To: gregoryjward@gmail.com

Dear Mr. Gregory Ward,

I am Sneha Jain pursuing MS in Building Science from International Institute of Information Technology Hyderabad, India. I have gone through this previous Radiance thread about running hdrgen on Linux. I have tried using hdrgen from anyhere.com but then I came to know that it only works on 32-bit system. Please let me know if there is any latest version of hdrgen available for 64-bit Ubuntu and if you can send me the same.

​Thank you.

Regards,

Sneha Jain

Hi Greg,

Thanks for the clarification regarding -s factor. I was getting some green
colored hdr images previously but now they are coming properly. It may be
due to the camera response function; now it seems to work fine with my
camera. Thank you for the help.

Regards,

Sneha Jain
M.S by Research in IT in Building Science,
Center for IT in Building Science Lab,
International Institute of Information Technology,
Hyderabad-500032, India

···

On Thu, Jul 13, 2017 at 11:03 PM, Gregory J. Ward <gregoryjward@gmail.com> wrote:

Hi Sneha,

Glad that worked for you. I'll include it in the package on my website
for future downloaders.

The -s factor doesn't have to be exact. It just has to have the correct
relative relation between captures. If you capture your images in the
usual 1-EV separation, you might use for example:

img1.jpg 1/60th second
img2.jpg 1/125th second
img3.jpg 1/250th second

hdrgen -s 1 img1.jpg -s 2.0 img2.jpg -s 4.0 img3.jpg

In other words, you want the pixels times the multipliers to roughly equal
each other (within the limits of exposure range). If you happen to know
what the absolute level of some image is, you can use that. Here is an
approximate formula for the -s factor based on ISO, f-stop, and exposure
time:

s2nits = 87*f_stop^2/(exp_time*ISO)

Cheers,
-Greg

*From: *Sneha Jain <sneha.jain@research.iiit.ac.in>

*Date: *July 13, 2017 5:36:55 AM PDT

Hi Greg,

Thank you so much for providing this version. I am glad to inform you that
this version is working with Linux 64-bit. Though I am struggling to
understand the -s stonits factor for each LDR image that I need to specify
for getting an HDR image. I am connected to a fish-eye lens all-sky camera
and unable to get this factor automatically. If you could suggest me on how
to get this; it would be really great.

Thank you.

Regards,

Sneha Jain
On Wed, Jul 12, 2017 at 7:40 PM, Gregory J. Ward <gregoryjward@gmail.com> > wrote:

Hi Sneha,

Try this version and tell me if it's any better. Building under Linux is
painful because of the required libraries (OpenEXR in particular).

Cheers,
-Greg

P.S. I "cleared" your post to the HDRI mailing list, but you need to
subscribe to the list using the address you post with in order for this to
be unnecessary.

*From: *Sneha Jain <sneha.jain@research.iiit.ac.in>

*Subject: *Request for hdrgen's updated version for Linux 64-bit system

*Date: *July 12, 2017 3:34:08 AM PDT

*To: *gregoryjward@gmail.com

Dear Mr. Gregory Ward,

I am Sneha Jain pursuing MS in Building Science from International
Institute of Information Technology Hyderabad, India. I have gone through
this previous Radiance thread
<https://radiance-online.org/pipermail/hdri/2012-August/000429.html>
about running hdrgen on Linux. I have tried using hdrgen from anyhere.com
but then I came to know that it only works on 32-bit system. Please let
me know if there is any latest version of hdrgen available for 64-bit
Ubuntu and if you can send me the same.

​Thank you.

Regards,

Sneha Jain