Hello David et al.
Just had a look at the "Easy HDR" site looks good and worth a try.
My current interest is in tone mapping and the algorithms used - please let me try to explain. The processing we are describing as HDR is actually a double barrelled process:
1. Creating a file that is capable of representing (encoding) the scene you are looking at rather than the common (& limited) colour gamut that is represented by the standard SRGB(TIFF format). To this end a number of encoding standards were invented. Eg. The formats XYZE and RGBE each encode in 32 bits per pixel. The problem is that no currently available display can display the colour gamut that may be accommodated by these formats so:
2. To represent these colours in the current displays (printers, CRT's etc) a process called tone mapping is used. The reason for tone mapping is best described in "A review of tone mapping techniques" by Kate Devlin, quote:
"The ultimate aim of realistic graphics is the creation of images that provoke the same response and sensation as a viewer would have to a real scene i.e. the images are physically or perceptually accurate when compared to reality."
A lot of this work is involved in modelling the human visual system and there is much research going on in this area so as some firms develop these algorithms they put them up for sale. As a result of this some code currently available will perform better than others - pity they do not publish their research results so we can really tell how much better one piece of code is better than another.
Jerry.
