Real-Time Bayer-Domain Image Restoration for an Extended Depth of Field (EDoF) Camera

Abstract

In this paper, we present a novel real-time image restoration approach using a truncated constrained least-squares (TCLS) filter and spatially adaptive noise smoothing (SANS) algorithm based on alpha map for the extended depth of field (EDoF) system in an image signal processing (ISP) chain. The proposed TCLS filter and the alpha map-based SANS algorithm can be implemented in the Bayer-domain by using a general finite impulse response (FIR) structure. The TCLS filter coefficients are priori determined according to the given point-spread-function (PSF) by optical lens simulation, and deconvolution is performed in the Bayer-domain instead of the RGB-domain. The SANS algorithm can successfully remove noise in flat regions without affecting the sharply restored details. Based on the extended set of experimental results the proposed algorithm is proved to be able to restore an accurately focused image in real-time, and is suitable for commercial low-cost, high-quality imaging devices such as a digital camera and a camcorder(1).