Abstract: A detection system on detecting a light source or an object irradiated by the light source serving as an object to be photographed with high accuracy and capturing a vivid image of the object to be photographed and a signal processing method and a smoke sensor. A detection system includes an image pickup unit, a light source, a first computing unit, a second computing unit, a third computing unit, a detecting unit, and a correction instructing unit. The correction instructing unit outputs a correction instructing signal when the absolute value of a computation result A or that of a computation result B exceeds a permissible decrement. The third computing unit corrects the computation result of which absolute value is reduced between the computation results such that the decrement is less than or equal to the permissible decrement when receiving the correction instructing signal, and performs computation.

Abstract: In a trick-action type clock, a part of an hour plate rotates along a plane parallel to a clock support plate. The trick-action type clock includes a first hour plate portion which is fixed to the clock support plate and has a circular shape, and a second hour plate portion which is rotated by a driving motor. The first hour plate portion includes an indicator needle shaft insertion portion which is provided at a position remote from a center of the first hour plate portion so as to insert an indicator needle shaft 101 therethrough. The second hour plate portion includes a circular notched hole which has a rotation center coincides with the center of the first hour plate portion with a circular shape and has the same shape as that of the first hour plate portion.