Building a high dynamic range video sensor with spatially nonregular optical filtering

摘要

Although we observe a steady progress in the development of High Dynamic Range Video (HDRV) technology,current image sensors are still lacking achievable dynamic range for high image quality applications. We proposea new imaging principle that is based on a spatial variation of optical Neutral Density (ND) filters on top of somepixels. In existing work, this method has been used to trade spatial resolution for an increase in dynamic range.We improve this approach by a non-regular placement of these filters. The non-regular sampling is an importantstep as any sub-sampling with regular patterns leads to aliasing. The non-regular patterns however preservejust a single dominant spatial frequency and enable an image reconstruction without aliasing. In combinationwith a new image reconstruction approach, we are able to recover image details at high resolution. The iterativereconstruction is based on the assumption that natural images can be represented with few coefficients in theFourier domain. As typical natural images can be classified as near-sparse, the method enables the reconstructionof images of high objective and visual quality. In extension to theory and simulation of this method wewant to present details on a practical implementation of our method. While building a demonstration systemwe encountered many challenges. This includes effects like crosstalk, aspects like sensor selection and maskfabrication as well as mounting of the masks.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.