Hello again,

Thank you all for the many hints. I tried it out and it works now.
But anyhow I have a following problem now.

When I do insert the following lines to the header for the description of our 
used angular fish eye lens, radiance tools like 'evalglare' (the author is J. 
Wienhold) does calculate wrong results.

#?RADIANCE
FORMAT=32-bit_rle_rgbe
VIEW= -vta -vv 180 -vh 180 -vp 0 0 0 -vd 0 0 1 -vu 0 1 0
EXPOSURE=1.79e+02

-Y 1040 +X 1392


I do assume this is due to the fact that the circular field of view for our 
fish eye is just a part of the rectangular aspect ratio of the image.
For example the center of the circular view is x = 700px; y = 500px and the 
diameter = 450px.
Is it possible to tell this within the header?

Another possibility could be to crop the image according to this circular field 
of view. Is this possible?

Kind regards
Tobias



Von: Gregory J. Ward [mailto:[email protected]]
Gesendet: Mittwoch, 23. Juli 2014 17:57
An: High Dynamic Range Imaging
Betreff: Re: [HDRI] Question about header information of HDRI

Well, you asked at the right place!  The Radiance header format is simple, a 
set of newline ('\n') separated comments, some of which are of the form:

VARIABLE=value

A space may appear after the equals ('=') but rarely/never appears before it.  
Other lines in the header do not have this form, and may be anything.  However, 
the first line identifying the file should be:

#?RADIANCE

The "RADIANCE" portion above is traditional, whereas the "#?" sequence is the 
so-called "magic number" for Radiance pictures.  Below is a typical information 
header:

#?RADIANCE
CAMERA= NIKON CORPORATION NIKON D700 version Ver.1.03
Photosphere created HDR image from '_DSC7719.JPG' '_DSC7720.JPG' '_DSC7721.JPG' 
'_DSC7722.JPG' '_DSC7723.JPG' '_DSC7724.JPG' '_DSC7725.JPG' '_DSC7726.JPG' 
'_DSC7727.JPG'
EXPOSURE=4.887013e-03
VIEW= -vtv -vh 51.765083 -vv 71.303574
OWNER= Greg Ward
CAPDATE= 2014:02:25 09:49:32
GMT= 2014:02:25 08:47:39
LATLONG= 46.948730 7.451972
FORMAT=32-bit_rle_rgbe

------
The header is terminated by an empty line (two newlines together "\n\n").  The 
following line after the empty line is very important, it contains the image 
resolution.  It is typically in the form:

-Y ysiz +X xsiz

where xsiz and ysiz are the integer number of pixels in the image.  This ASCII 
string is terminated by another newline ('\n'), immediately followed by the 
raster image data in the order indicated, Y (vertical) major sort, with Y 
values decreasing as measured from the bottom-left of the image.  This is 
explained in more detail in the relevant section (pp. 28-35) of the Radiance 
file formats document, located here:

                http://radsite.lbl.gov/radiance/refer/filefmts.pdf

I see Lars has provided you with the same information.  I hope this is enough 
to get you started.  Please note the importance of the EXPOSURE= line in the 
header and the 179 lumens/watt standard conversion factor in creating a 
properly calibrated picture.

Let me know if you have further questions.

Best,
-Greg



From: Tobias Porsch 
<[email protected]<mailto:[email protected]>>

Subject: [HDRI] Question about header information of HDRI

Date: July 23, 2014 8:27:01 AM PDT


Hi,

I'm writing you concerning my current project.
I'm working for TechnoTeam company. Manyfacturer of imaging luminance measuring 
devices (camera photometer).
Our aim is to export our own image file format (pixel-wise HDR float values) 
into the Radiance rgbe file format.
The aim is to give radiance users access to the measured luminance information 
combined with our information about lens configuration (geometrical data).
This may of interest for the "glare" community when analyzing the glare using 
radiance tools.

Anyway, writing the rgbe information is no problem.

But what about the header structure of the radiance HDRI format?
I'm a little confused about it and can't find a documentation structure how it 
is organized?
Unfortunately I'm no radiance user for carrying out own radiance projects to 
study it?

With my best regards
Dipl.-Ing. Tobias Porsch
TechnoTeam Bildverarbeitung GmbH
Werner - von - Siemens - Strasse 5
98693 Ilmenau
----------------------------------------------------------------------------
Email:  [email protected]<blocked::mailto:[email protected]>
Phone: +49 3677 4624 0

TechnoTeam Bildverarbeitung GmbH
Geschäftsführer: apl. Prof. Dr.-Ing. habil. F. Schmidt
Standort: Ilmenau
Handelsregistereintrag: Jena HRB 300912


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