Compound-eye-based multidimensional imager

In imaging applications, such as security or biomedical imaging, increasing the number of dimensions of acquirable optical signals could help identify and classify objects in the image. However, conventional approaches to gain additional information, such as depth or spectral data, with a 2D image sensor, sacrifice spatial or temporal resolution. We have developed two promising approaches using compound-eye optics for future imaging systems that capture and make use of the additional dimensions without sacrificing resolution. Our first approach is based on compressive sensing to observe the multidimensional signals. The optical design modulates each dimension, and a sparsity-based reconstruction solves the (ill-posed) inverse problem. The second approach uses dimensionally invariant optical design and signal processing to observe a 2D image of a 3D object with a wide field of view (FOV) and an extended depth of field (DOF). The visual organs of insects and crustaceans are compound eyes. They are composed of lenslets, partitions, and detectors as shown in Figure 1. In the apposition type, each detector optically connects to a single lenslet. In the superposition type, a detector connects to multiple lenslets. Both types have unique features and are used in various innovative imaging systems, notably for compact imaging hardware.1 Optical signals have multiple dimensions, including 3D position (x; y; z), time (t ), wavelength ( ), and polarization (p). Conventional approaches to observing these parameters with an image sensor compromise the lateral spatial resolution (x; y) or the temporal resolution. We have introduced an apposition compound eye for single-shot multidimensional imaging based on compressive sensing (CS).2 In this approach, the basic optical unit in the compound eye—made up of a lenslet, detector (sensor), and partition—is differently modulated in each physical dimension except the lateral spatial ones (x; y). Figure 2 shows Figure 1. (a) Apposition and (b) superposition compound eyes.