pvalue related question

radiance-general
1

Hello list, I am trying to find lux levels from an image created with
radiance.

I believe that I have made a mistake on the parameters because the values I
read are mostly bellow 1 (lux???)

Rendering the image I can see that lux levels are much higher, up to 100
lux.

The parameters I am using with pvalue are the following:

"pvalue -h -o -b"

Any suggestions, cause I feel somehow lost???

Thanks in advance

Sotiris

2

Radiance images store radiance values. You have to convert the raw values
with the appropriate luminous efficacy value (179 by default). This only
makes sense if the image was rendered with "-i" as an option to rpict and
has not been passed through pcond.

Solution: add rcalc to your command

pvalue -h -H -b -o image.hdr | rcalc -e '$1=$1;$2=$2;$3=$3*179'

Regards,
Thomas

···

2011/6/10 Σωτήρης Παπαντωνίου <[email protected]>

Hello list, I am trying to find lux levels from an image created with
radiance.

I believe that I have made a mistake on the parameters because the values I
read are mostly bellow 1 (lux???)

Rendering the image I can see that lux levels are much higher, up to 100
lux.

The parameters I am using with pvalue are the following:

"pvalue -h -o -b"

Any suggestions, cause I feel somehow lost???