Mitigating Sensor Saturation through Image Processing Techniques

ABSTRACT: We propose a novel multi-frame image processing approach which employs High-Dynamic-Range (HDR) imaging in combination with model-based lens-flare estimation as a means of mitigating focal plane saturation and lens flare when extremely bright sources are present in MWIR imagery. Collecting multiple image frames with varying optical flux densities provides information over a diverse set of dynamic ranges. Additionally, the temporal variation of lens-flare artifacts over multiple frames differs statistically from that of the underlying scene content. Our technique provides a robust methodology for exploiting this information to restore and even enhance MWIR imagery adversly effected by extremely bright scene content. BENEFIT: There will be immediate benefits in military applications of this technology to surveillance, reconnaissance, and target acquisition and tracking. For example, this technology may be used to mitigate the saturation effects of directed energy"laser dazzlers"on guided missile electro-optics. Since the methods developed in this project will not be specific to the MWIR band, they may be more generally applied over the visible to LWIR range of imaging devices. Programmable consumer digital cameras in the visible band could eventually be controlled with these algorithms, presenting a large market for this technology. Multiple frames with exposure times covering the full dynamic range of intensities in the scene would be automatically taken, with a composite HDR image then constructed from these frames. Lens flare due to reflections internal to the camera would also be reduced using the methods devised here.