Narrow Line Detection for a Flying Spot Scanner
Original Publication Date: 1980-Jul-01
Included in the Prior Art Database: 2005-Feb-13
In a flying spot scanner the video signal output from the scanner may not remain above a threshold level long enough to be sampled by a set of sampling pulses. The narrow video signal stems from scanning narrow line text, low contrast documents, and out-of-focus lines. Fig. 1 shows, in block diagram form, a configuration for a typical flying spot scanner. The optical signal (0) from the flying spot optics is detected by the detector. The output from the detector is fed into a current/ voltage amplifier (K) which generates an output signal (V). The video signal (V) is fed into one leg of a thresholder. A threshold level circuit generates a threshold voltage (T) which is supplied to the other leg of the thresholder. The thresholded video signal (VT) is fed into a sampler S.