| 摘要 |
PURPOSE:To inexpensively and instantaneously extract the noticeable part of an object by providing a light source which can irradiate the object to be measured from a direction in which information held by reflecting lights can be separated easily, lens system which forms the image of the reflecting lights and filter which controls the above mentioned information holding information at the vicinity of the focal surface of the lens system. CONSTITUTION:Incident light 102 are vertically made incident on a time piece 803 set perpendicularly to the optical axis 101 of a lens system 105 by using a half mirror 809. Reflecting lights 104 of the incident lights 102 form an image on an image forming plane 108 through a lens system 107 after forming a diffracted image on a focal surface 106 through the lens system 105. Since the cross section of hands 906 of time pieces usually have roof-like shapes, the hands 906 produce reflecting lights 906 in directions which are different from the direction of reflecting lights produced by dial plates. The zone A0 on the focal surface 106 is an area where bundle of rays containing information of names of manufacturers, clock glass, etc., which are not required for reading hands on the dial plates are concentrated. Zone B0 and B1 are areas containing the information of hour hands and those C0 and C1are areas containing information of minute hands. When a filter 1002 which intercepts the area A0 only is inserted, pictures of minute hands and hour hands only are extracted.
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