Question about the falsecolor in the exercise of Radiance_tutoral.pdf Chapter 5 p35

radiance-general
1

Hi everyone,

I am new to Radiance and am following the tutorial material to learn it. But for the command in p35 as follows. I do not find anywhere in the book to introduce how to generate “scene_i.hdr”.
"
falsecolor -i images/scene_i.hdr -p images/scene.hdr -cl -n 10 -s 2000 -l lux > images/false.hdr
"
Does anyone the function of scene_i.hdr and how to generate it?

Warm regards,

Hao

3

Hi Hao,

if you are using LINUX, please type

man rpict

otherwise, go to
https://www.radiance-online.org/learning/documentation/manual-pages
and download the man page for rpict in PDF format.

Either way, you want to search the man page on how to render an irradiance image.

For future posts, could you please be more specific with the subject line, and don’t cover more than one subject per discourse thread.

A

4

Hi Alex,

Thanks a lot for your reply and suggestions. I will follow your suggestions for future topics.

But I am still confused about this command. I learned the command and the way to generate HDR type files. But in this command, it uses “images/scene_i.hdr” directly and does not introduce how or why to generate this file. I know the hdr type file can be generated by “rpict”, but for this “images/scene_i.hdr”, why use it here or the requirements for generating this file is unclear. It just in the command and when you follow this command line it will show:“images/scene_i.hdr: No such file or directory”.

falsecolor -i images/scene_i.hdr -p images/scene.hdr -cl -n 10 -s 2000 -l lux > images/false.hdr

Cheers,

Hao

5

Hi Hao,

you need to run rpict twice (with and without the -i option). See the flow chart in Fig 28.

The man page of rpict explains what the -i option does:

−i Boolean switch to compute irradiance rather than radiance values.

A

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