tone mapping
DESCRIPTION
Tone Mapping. Application to Photography. Software Photomatix Pro. www.hdrsoft.com. Reality-Based Visualization. Konferenz und Workshop '05. Tone Mapping Operators – Global vs Local. Two categories of Tone Mapping operators : - PowerPoint PPT PresentationTRANSCRIPT
Tone Mapping
Software Photomatix Pro
Application to Photography
www.hdrsoft.com
Konferenz und Workshop '05Reality-Based Visualization
www.hdrsoft.com 2
Tone Mapping Operators – Global vs Local
Two categories of Tone Mapping operators: Global: each pixel is scaled based on its intensity and
global image characteristics
Local: pixels' surroundings taken into account for scaling (in addition to intensity and image characteristics)
Main advantage is fast processing
Necessary for "good-looking" photograph, human eye adapts to contrast locally
www.hdrsoft.com 3
Example Local TMO – Photomatix Pro
32-bit HDR Image as viewed on computer screen
Dynamic Range captured: ~ 30,000:1 (~ 15 EV)
Dynamic Range reproduced: ~ 500:1 (very rough estimate)
HDR Image after Tone Mapping in Photomatix Pro
Dynamic Range reproduced:roughly same as DR captured
www.hdrsoft.com 4
Tone Mapping vs Exposure Blending
Exposure Blending: Combining differently exposed 8-bit images into another 8-bit image containing details in highlights and shadows of each exposure
Tone Mapping: Processing HDR image directly (i.e. "real" light values captured) to compress range down to 8 bits for correct display on standard monitors
Advantage: easy to understand, you can see what you are doing
Advantage: if well done, accurately reproduces original scene (as seen at capture time)
www.hdrsoft.com 5
Tone Mapping vs Exposure Blending
Exposure Blending with Photomatix Pro "H&S Details – Auto"
Tone Mapping with Photomatix Pro
1/750 sec.
1/180 sec.
1/45 sec.
www.hdrsoft.com 6
Tone Mapping: Realistic results?
Typical reaction Photographer
Your Tone Mapping result does not look "natural" to me. It looks more like a painting than a
photograph!
But I was there and this is exactly what I saw. I would not have taken
the picture if it had been looking like a dull
photograph!
Conclusion: Tone Mapped images better reflect reality seen. However, we are so used to viewing Low Dynamic Range photos, that we do not expect what Tone Mapping produces and may find it unrealistic.