• We proposed a novel detector array for detecting and localizing particle-emitting sources, whose configuration is inspired by the biological compound eye but generalizes it. The array consists of multiple "eyelets" (similar to ommatidia), each having a conical module with a lens on its top and an inner sub-array containing a large number of small particle detectors.
• The eyelets can be used to detect uncharged particles such as photons and neutrons. The proposed array combines the advantages of the biological compound eye (large FOV) and of human eyes (high spatial resolution). Moreover, the size of the array is compact compared with other distributed sensor arrays.

Fig. 2: The compound-eye-inspired particle detector array.

• We derived a rigorous general mathematical model for the proposed array by rigorously defining several basis concepts and assumptions, proposing a basis function presentation for the array's transfer function, and optimizing that basis.
• We analyzed the array performance by computing statistical Cramer-Rao bounds (CRBs) on the errors in estimating the direction of arrival of the incident particles, deriving a lower bound on the mean-square angular error (MSAE) of source localization for a specific array, introducing a universal lower bound on the MSAE for an arbitrary spherical array in principle, and investigating the MSAE of two source direction estimators.
• We numerically compare the performance of the proposed array with the biological compound eye, optimally design the array configuration, show that both source direction estimators can asymptotically attain the performance bound, and analyze the hardware efficiency by comparing the two MSAE bounds.
• Potential applications include artificial vision in medicine (e.g., artificial eye for the blind) or robotics (e.g., for industry or space missions), astronomy (e.g., for remote stars), security (e.g., for nuclear materials), and particle communications.
  
  

Fig. 3: Comparison of source localization accuracy between the biological compound eye and the proposed array.
Left: The compound eye, Right: The proposed array.

• A. Nehorai, Z. Liu, and E. Paldi, "Optimal design of a generalized compound eye particle detector array," Proc. SPIE Vol. 6232, Intelligent Integrated Microsystems, 62320O, 14 pages, Orlando, FL, Apr 2006.
  
• Z. Liu, A. Nehorai, and E. Paldi, "Statistical analysis of a generalized compound eye detector array," Proc. 4th IEEE Sensor Conference, 4 pages, Irvine, CA, Oct-Nov 2005.
• Z. Liu, A. Nehorai, and E. Paldi, "A biologically inspired compound-eye detector array: part I - modeling and fundamental limits," in revision for IEEE Trans. on Signal Processing.
• Z. Liu, A. Nehorai, and E. Paldi, "A biologically inspired compound-eye detector array: part II - statistical performance analysis," in revision for IEEE Trans. on Signal Processing.