Fig. 1. Creating synthetic apertures to improve image resolution.

Objects illuminated with a coherent wave reflect a signal back toward the detector that diffracts to an area larger than the aperture of the receiver. (A) SAR is a technique to increase the resolution of mobile radar imaging systems by scanning the antennae over the synthetic aperture. (B) We extend the principles of SAR to create SAVI. A coherent source (for example, a laser) illuminates a distant target, and the reflected signal is captured by a camera. The camera system is translated to capture all of the light that would enter the desired synthetic aperture. Unlike SAR, phase information cannot be recorded for visible light. Therefore, high-resolution image reconstruction necessitates postcapture computational phase recovery. (C) Experimental implementation of SAVI in three steps. (1) A diffuse object is illuminated with a coherent source, and overlapping images are captured. Each image has low resolution and suffers from speckle. (2) Missing phase information is recovered computationally, which requires redundancy between captured intensity images. (3) A high-resolution image is reconstructed using the recovered phase. Additional examples of captured data and reconstructions are shown in Figs. 3 and 4.