Glare aware photography

Ramesh Raskar, Amit Agrawal, Cyrus A. Wilson, Ashok Veeraraghavan
2008 ACM SIGGRAPH 2008 papers on - SIGGRAPH '08  
Glare Reduced Captured Photo Glare Enhanced Figure 1 : We extract glare components from a single-exposure photo in this high dynamic range scene. Using a 4D analysis of glare inside the camera, we can emphasize or reduce glare. The photo in the middle shows a person standing against a sunlit window. We extract reflection glare generated inside lens and manipulate it to synthesize the result shown on the left. On the right we show the glare-reduced component. Notice that the face is now visible
more » ... ith improved contrast. Abstract Glare arises due to multiple scattering of light inside the camera's body and lens optics and reduces image contrast. While previous approaches have analyzed glare in 2D image space, we show that glare is inherently a 4D ray-space phenomenon. By statistically analyzing the ray-space inside a camera, we can classify and remove glare artifacts. In ray-space, glare behaves as high frequency noise and can be reduced by outlier rejection. While such analysis can be performed by capturing the light field inside the camera, it results in the loss of spatial resolution. Unlike light field cameras, we do not need to reversibly encode the spatial structure of the rayspace, leading to simpler designs. We explore masks for uniform and non-uniform ray sampling and show a practical solution to analyze the 4D statistics without significantly compromising image resolution. Although diffuse scattering of the lens introduces 4D low-frequency glare, we can produce useful solutions in a variety of common scenarios. Our approach handles photography looking into the sun and photos taken without a hood, removes the effect of lens smudges and reduces loss of contrast due to camera body reflections. We show various applications in contrast enhancement and glare manipulation.
doi:10.1145/1399504.1360655 fatcat:dbyrcxwifveazksidtpoe7kqse