| 摘要 |
<p>One aspect of the invention is a scanner operable to scan a tangible medium having an image thereon. The scanner has a first light source and a second light source wherein the second light source is an infrared light source. The scanner further comprises sensing circuitry operable to produce a first electric signal responsive to the intensity of light reflected from at least one pixel area of the tangible medium in response to light produced by the first light source and to generate a first data value in response to the first electric signal. The sensing circuitry is further operable to produce a second electric signal responsive to the intensity of light reflected from the at least one pixel area in response to the light produced by the second light source and to generate a second data value responsive to the second electric signal. The second data value may be used to predict the existence of a defect in a digital representation of the image.</p> |
