| 摘要 |
An optical scanner utilizes two linear CCD detectors and a bandpass means to improve the ability of the scanner to discriminate against specular reflection. A coded symbology is illuminated by a noncoherent light source and light reflected from the coded symbology along a first path strikes the front face of the bandpass means. The bandpass means, functioning as a notch filter, transmits a select bandwidth of light while reflecting all other light onto a first CCD detector. Simultaneously, light reflected from the bar code symbol travels along a second path, at a different angle with respect to the plane of the coded symbology than the first path, is reflected from a mirror onto the back face of the bandpass means. The bandpass means transmits the select bandwidth of light onto a second CCD detector and reflects all other light. The second CCD detector has a notch filter which permits the detection of only the select bandwidth. Since specular reflection is only experienced at a single angle, with respect to the plane of the coded symbology and each CCD detector detects an image at a different angle with respect to the plane of the coded symbology, a complete image can be reconstructed by combining information obtained from both CCD detectors.
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