Fig. 1: Concept and principle of the artificial compound eye for a panoramic camera (ACEcam) that uses conical-microlens optical fibres to mimic natural ommatidia.

a The fly Choerades fimbriata has natural compound eyes (NCEs) for imaging; photograph courtesy of Mr. Thorben Danke of Sagaoptics. The inset shows compactly arranged corneal facet lenses in the NCEs. b In a natural ommatidium, the facet lens with a focal length f collects light at a specific acceptance angle Δφ, the crystalline cone ensures light convergence, the rhabdom (diameter d) transmits light through the inner structure, and the photoreceptor cell records the light information. c An NCE consists of numerous natural ommatidia, which are surrounded by pigment cells to prevent crosstalk. Here, the interommatidial angle ∆Φ = D/R, where D and R denote the arc distance of adjacent ommatidia and the local radius of curvature, respectively. d Comparison of different compound eyes in the functions of static panoramic imaging and dynamic motion detection. The 1st generation ACEs primarily focused on the fabrication of ACE microlenses, lacking the ability of static imaging or dynamic detection. In the 2nd generation ACEs, none of these ACEs could realise real-time panoramic direct imaging and dynamic motion detection simultaneously, as what the NCEs can do. In contrast, our ACEcam is comparable to the NCEs in aspects of 180^o field of view and static imaging, and surpasses the NCEs in ultrafast motion detection. e An artificial ommatidium closely resembles a natural ommatidium by using a microlens to mimic the facet lens and the crystalline cone, an optical fibre core to mimic the rhabdom, an optical fibre cladding to mimic the pigment cells, an imaging lens to mimic synaptic units to focus each optical fibre onto an individual photodetector, and a photodetector in the flat imaging sensor chip to mimic the photoreceptor cell. f An artificial compound eye consists of numerous artificial ommatidia, with a flat imaging sensor chip mimicking the deeper neural centres (medulla and lobula), where signals are pre-processed. The signals are then transmitted to a computer for further analysis