Label/window position detecting device and method of detecting label/window position

A label/window position detecting device comprising:

• convey means for conveying a target object having a label/window;
• light-emitting means for illuminating the target object which is being conveyed by said convey means;
• wherein said light-emitting means comprises a plurality of light-transmitting portions for emitting light components having specific wavelength bands different from each other;
• optical means for forming images of the target object illuminated with said light-emitting means;
• photoelectric converting means for photoelectrically converting image light incident through said optical means into image signals;
• wherein said photoelectric converting means comprises a plurality of photosensor units having sensitivities to only the light components having the specific wavelength ranges from said light-emitting portions;
• image processing means for binarizing the image signals obtained from said photoelectric converting means into monochrome binary image signals, using a predetermined threshold;
• label/window position calculating means for calculating a label/window position of the target object on the basis of the binary image signals from said image processing means, which correspond to at least one of leading and trailing edge portions of the label/window perpendicular to a convey direction of the target object;
• a half mirror for reflecting and transmitting the light components having the specific wavelength bands from said plurality of light-emitting portions through said optical means upon reflection by the target object;
• and
• a pair of optical filters for filtering only the light components having the specific wavelength bands different from each other from light reflected by said half mirror and light transmitted through said half mirror;
• wherein said photoelectric converting means comprises a pair of photoelectric converting elements, having sensitivities to only the light components having specific wavelength bands which have passed through said optical filters, for outputting photoelectrically converted image signals respectively representing leading and trailing end positions of the label/window.