Direct HDR Capture of the Sun and Sky:

AFRIGRAPH 2004 Paper
SIGGRAPH 2004 Poster

Jessi Stumpfel   Andrew Jones   Andreas Wenger

Chris Tchou   Tim Hawkins   Paul Debevec

USC Centers for Creative Technologies

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Abstract:

We present a technique for capturing the extreme dynamic range of natural illumination environments that include the sun and sky, which has presented a challenge for traditional high dynamic range photography processes. We find that through careful selection of exposure times, aperture, and neutral density filters that this full range can be covered in seven exposures with a standard digital camera. We discuss the particular calibration issues such as lens vignetting, infrared sensitivity, and spectral transmission of neutral density filters which must be addressed. We present an adaptive exposure range adjustment technique for minimizing the number of exposures necessary. We demonstrate our results by showing time-lapse renderings of a complex scene illuminated by high-resolution, high dynamic range natural illumination environments.

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material:

AFRIGRAPH 2004 Paper:

• Skycapture_afrigraph2004.pdf, 2.7 MB. ( Adobe Acrobat )

Jessi Stumpfel's Master's Thesis:

• Ms_thesis_stumpfel.pdf, 7.5 MB. ( Adobe Acrobat )

SIGGRAPH 2004 Poster:

• Skycapture_poster.pdf, 2 MB. ( Adobe Acrobat )

SIGGRAPH 2004 Video:

• Skycapture_poster.mov, 29.54 MB. ( Quicktime 3:00 min )

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ADDITIONAL RESOURCES :

For capturing the sky we used a Canon EOS-1ds with a Sigma 8mm lens. To control the camera, we used the Canon Digital Camera SDK. This C library provides the ability to set camera settings such as F-stop and exposure time, release the shutter remotely, and download images via firewire or USB.

Sample images representing 2/23/2004 are available for download skyprobes.zip (62MB)

The images are at taken 10 minutes intervals from sunrise to sunset and have been subsampled to 1k resoluton. Please Note: The images in this dataset are quite bright, with sky pixel values in the range of 100-500. You may need to expose the images lower (e.g. hitting the "-" key around 10 times in HDR Shop) to view them, otherwise they can appear completely white. The full dataset (1 minute intervals, 4k resolution) is availble on request.