Author: Christian Bloch
Publisher: Rocky Nook, 2007
Aimed at: Photographers
Pros: Relates to exciting new software techniques
Cons: Not written for developers
Reviewed by: David Conrad
This is a book aimed at photographers but if you are into graphics you are bound to be excited by it. I have to warn you that it covers a lot of very basic photographic concepts that sometimes threaten to cover up the real idea. HDRI – High Dynamic Range Imaging – is a simple enough idea, just record an image with much higher dynamic range than the usual eight bits per colour channel.
The problem with this idea is that at the moment there aren’t any HDRI cameras so we have to emulate one by taking multiple exposures at different settings – one to capture the detail in the shadow, one for the mid tones and one for the highlights. These can then be put together to make a composite HDRI image using the right software. In practice you need more than three exposures to enable the software to knit the images together.
Once you have an HDRI image you generally have to map it to a normal dynamic range display and this again requires some more software. The pay off is that by careful mapping of the out of range luminance values the results can be stunning – retaining detail across the entire tonal range of the image. What has all of this to do with programmers? The answer is that the software to do all of this is in its infancy. The book describes some of the file formats, algorithms and applications that are available to work with HDRI but there is clearly a lot of scope for inventing something new.
HDRI is new territory and this is its first guide book.
<Reviewed in VSJ>