How to adjust for the human eye?


#1

I’m a bit curious on the best way to adjust the output for the human eye. Why does ximage -e human use the -s and -c options only, instead of the -h option offered by pcond, which applies the −a, −v, −s and −c options?

Apart from that, are there any rules of thumb I can follow in adjusting exposure or colour balance? Will I be compromising the scientific validity of “human perception” if I adjust the exposure or colour balance?

Also, can I also adjust the glare effect? Sometimes I feel as though pcond -v is too harsh or sometimes, not harsh enough.

I understand it’s all a bit fuzzy, but hopefully I’d like to learn a bit more :slight_smile:


#2

Pcond is not a perfect simulation of the human eye, but it’s attempting to perform a very difficult task, that is, reproduce the percept of a high dynamic-range scene on the limited dynamic range of a display. It has no way to account for the surrounding environment, which it would really need to do to get it right. The paper describing the technique is:
Larson, G.W., H. Rushmeier, C. Piatko,
A Visibility Matching Tone Reproduction Operator for
High Dynamic Range Scenes
,” IEEE Transactions on Visualization
and Computer Graphics, Vol. 3, No. 4, December 1997.
Regarding the options included by ximage, I have implemented a fast and efficient tone-mapping for ximage and similar tools, but it cannot do everything pcond can do, hence no simulation of acuity loss and disability glare, which are expensive to compute.