SGER: Computational Photography: Lighting and Focus

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Intellectual merit: The proposed research program will integrate concepts from both computer graphics and photography, drawing on the extensive experience of the PI in both endeavors. The underlying notion is the application of computer graphics techniques to photography to solve fundamental shortcomings in the photographic process. This involves extending our thinking for algorithm development beyond what is physically realizable.Methods: For a group photograph that has non-uniform illumination, we will develop brightnesscompensation techniques to modify an exposed portrait such that every face would have approximately the same brightness. Our approach will extract underexposed facial regions with their average brightness values and locations, and then compensate for their underexposure by adding brightness according to the classification of the layout of the subjects. The proposed method will involve a sequence of image processing steps: extracting skin-colored objects and facial regions, extracting and determining a layout classification, and adding brightness using average brightness and spatial variation.To achieve generalized control over focus in photography, we propose to develop algorithms that will combine and process photographs. One approach will involve first taking many pictures, each with different focus settings, and then combining these images to produce a composite in which only the desired region is in focus. It will be possible to quickly take many different pictures with precisely calibrated focus settings using a digital camera under the control of our software. In the case of a moving scene that would appear different in different exposures if multiple exposures were taken, we propose a different approach that synthetically adds blur as a postprocess, to closely approximate the desired effect.Impact: The results of this research could have applications in various aspects of digital photography, both for cameras and software, and will impact the nascent and currently inchoate field of computational photography. Our algorithms will initially be prototyped as software on a computer as a postprocess, but eventually we hope to see them integrated into the firmware of digital cameras.