Swiss scientists have developed an artificial faceted eye

    Faceted eyes , consisting of many narrow light-sensitive cones called ommatidia, are characteristic of insects and crustaceans. Although they have lower resolution than the eyes of vertebrates, they have several advantages - they are less inertial (some insects are able to perceive flickers with a frequency of up to 300 Hz), do not require focusing and can distinguish not only color but also the direction of polarization of light. A team of scientists from the Lausanne Federal Polytechnic School (EPFL) has created a prototype of an artificial facet eye that takes advantage of this design.



    The artificial eye that scientists called CurvACE(CURVed Artificial Compound Eyes), consists of 630 "ommatidia", each of which is a photosensitive element and a microlens focusing on it a narrow beam of light. The eye has a viewing angle of 60 degrees in the vertical and 180 in the horizontal plane. The vertical angles of view of different ommatidia are given by the shape of the microlenses, and horizontally by the curve of the substrate on which the eye is located. This form is dictated by the manufacturing technology - photosensitive elements are formed on a solid crystal, which is then cut into narrow strips.



    The eye has a volume of only 2.2 cubic centimeters and weighs 1.75 grams. In industrial production, the current level of technology will reduce its size by at least half. The main purpose of the eye is visual navigation systems for robots. The eye has a high sensitivity and dynamic range - each ommatidium can individually adapt to the level of illumination. Such an eye cannot be blinded by solar flare. In combination with high speed (the prototype can produce up to 1500 frames per second), small size, no distortion along the edges of the field of view and the ability to relatively easily achieve a circular or even spherical view, this makes it an ideal tool for determining the position of the robot in space, detecting obstacles and collision avoidance.



    According to its characteristics, CurvACE approximately corresponds to the eye of the fruit fly of Drosophila. Although this is not the first attempt to create an artificial faceted eye, the development of Swiss scientists differs thoroughly - their goal is to create a comprehensive solution for navigation, and not just an optical sensor. As well as the insect's eye, which contains the nerve node inside for the primary processing of the image, the CurvACE includes a microcontroller that processes the signal from the sensors using optical flow algorithms , as well as an accelerometer and gyroscope. On the project website you can download libraries for working with the eye.

    Actually, the electronic filling accounts for most of the mass and volume of the eye - the array of CMOS sensors with micro lenses is 1 mm thick and weighs 0.36 grams. The ability to give the facet camera any shape and the absence of large lenses opens up many possibilities: these "eyes" can be built into the walls of rooms, in clothes or furniture for use in smart home or video surveillance systems. By combining different types of ommatidia in one sensor, you can create a camera that will see simultaneously in different ranges.

    CurvACE development has been underway since 2009. The total project budget is 2.73 million euros. An article with a detailed description of the project is available at this link .


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