An electromechanical transducer includes a plurality cells that are electrically connected to form a unit. Each of a plurality of illuminating lens units arranged in the illuminating optical passage has a barrel containing a plurality of lenses, and caps are so provided as to be spaced from the lenses at both ends. The computer is also configured to form a preliminary image based on the acquired plurality of far-field datasets, and apply an expectation maximization algorithm to the preliminary image; wherein the EM algorithm includes an ordered subset algorithm. Similarly, address resolution protocol response packets sent by the operating system in response to ARP request packets are intercepted, modified and redirected to receive NICs selected by the hash engine for transmission. Then, the filtering means is moved so that the light beam is projected onto a predetermined location to obtain the desired color temperature.