Many computational imaging applications involve manipulating the incoming light beam in the aperture and image planes. However, accessing the aperture, which conventionally stands inside the imaging lens, is still challenging. In this paper, we present an approach that allows access to the aperture plane and enables dynamic control of its transmissivity, position, and orientation. Specifically, we present two kinds of compound imaging systems (CIS), CIS1 and CIS2, to reposition the aperture in front of and behind the imaging lens respectively. CIS1 repositions the aperture plane in front of the imaging lens and enables the dynamic control of the light beam coming to the lens. This control is quite useful in panoramic imaging at the single viewpoint. CIS2 uses a rear-attached relay system (lens) to replace the aperture plane behind the imaging lens, and enables the dynamic control of the imaging light jointly formed by the imaging lens and the relay lens. In this way, the common imaging beam can be coded or split in the aperture plane to achieve many imaging functions, such as coded aperture imaging, high dynamic range (HDR) imaging and light field sampling. In addition, CIS2 repositions the aperture behind, instead of inside, the relay lens, which allows the employment of the optimized relay lens to preserve the high imaging quality. Finally, we present the physical implementations of CIS1 and CIS2, to demonstrate (1) their effectiveness in providing access to the aperture and (2) the advantages of aperture manipulation in computational imaging applications.

• Xianbiao Shu and N. Ahuja, Aperture access and manipulation for computational imaging, Computer Vision and Image Understanding (CVIU), Volume 116, Issue 2, February 2012, Pages 222-237.