How to make a small phone camera shoot like a big DSLR: creating and fusing multi-modal exposure series

摘要

The present work aims at improving the image quality of low-cost cameras based on multiple exposures, machine learning, and a perceptual quality measure. The particular implementation consists of two cameras, one being a high-quality DSLR, the other part of a cell phone. The cameras are connected via USB. Since the system is designed to take many exposures of the same scene, a stable mechanical coupling of the cameras and the use of a tripod are required. Details on the following issues are presented: design aspects of the mechanical coupling of the cameras, camera control via FCam and the Picture Transfer Protocol (PTP), further aspects of the design of the control software, and post processing of the exposures from both cameras. The cell phone images are taken with different exposure times and different focus settings and are simultaneously fused. By using the DSLR image as a reference, the parameters of the fusion scheme are learned from examples and can be used to optimize the design of the cell phone. First results show that the depth of field can be extended, the dynamic range can be improved and the noise can be reduced.