JPS57121768A - Symbol image pickup method and symbol recognizing device - Google Patents

Abstract

PURPOSE:To take an image of a symbol which has appeared on the surface of an object, with a dielectric, by constituting a device so that an irradiation light beam which has been polarized linearly is made incident, reflected rays from both the metallic surface and the dielectric surface are suppressed, and also the image can be taken by internal reflected rays from the inside of the dielectric. CONSTITUTION:An irradiation light beam 14 emitted from a polaroid filter 8 is reflected by th surface of a plate material 10, and a part of its reflected light beam reaches a polroid filter 26. By an operation of the polaroid filter 26, passage of an internal reflected ray 40 is allowed, but passge of reflected rays 36, 38 are stopped. A television camera 22 photodetects only the internal reflected ray 40 having uniform intensity corresponding to lightness of a coating film 18, supplies a video signal SM of a good quality containing no noise by the surface reflected rays 36, 38, and a picture processing circuit 30 sets the signal SM of the part for photodetecting the internal reflected ray 40, to ''1'' (bright), and supplies a picture signal SV converted to a binary signal, to both a monitor televison receiver 32 and a pattern discriminating circuit 34.