Abstract: This invention relates to a system for optically playing back recorded signals from a recorded medium on which signals of images or sounds are continuously recorded so as to constitute a signal recorded line or signal track. In play-back the images or sounds are optically recognized by the width-change of the signal recorded line. A narrow light beam for the play-back is deflected at a predetermined frequency in the direction perpendicular to the signal recorded line, i.e. in the direction of the width of the signal recorded line, in order to perform the optical scanning. The narrow light beam which is reflected or transmitted on the recorded medium surface reaches photo-sensitive elements such as photo-diodes.

Abstract: A tensile testing system for use with a specimen of rubber or other material having a test region defined on its reduced midportion by a marking or markings of, for example, higher lightness than the other specimen surface. The system comprises a scanning device for repeatedly translating the optical characteristics of the specimen or specimens into an electrical signal as the specimen or specimens are subjected to increasing tensile stress, and a gate circuit for deriving from the output signal of the scanning device its portions corresponding to the test region or regions. The varying length of the test region or regions can be represented either by pulse durations or by pulse numbers. The scanning device can be either an "area scanner" such as a television camera or a "line scanner" such as a solid-state line image sensor. Various embodiments are disclosed.