Signal processor method and apparatus
Code recognition record medium and technique
Method and apparatus for inverting the polarity of an input image formed on a surface of an image recording device
Holographic opaque document scanner
Hand held optical reading device
Laser tuning with an acousto-optic lens
ApplicationNo. 480802 filed on 06/07/1995
US Classes:235/462.27, Analog to square wave converter (e.g., digitizer, binarizer, slicer)327/73Reference derived by feedback
ExaminersPrimary: Shepperd, John W.
Attorney, Agent or Firm
Foreign Patent References
International ClassG06K 007/10
AbstractA multiple sensitivity-mode digitizer circuit for a bar code reader has circuits that perform two thresholding techniques. The bar code reader includes a first derivative circuit for receiving an analog signal from a scan of the bar code symbol and for generating a first derivative signal of the analog signal. The digitizer circuit includes a first thresholding circuit for generating a first digitized signal in response to a comparison between the first derivative signal and a first threshold representing a first detection sensitivity. A second thresholding circuit generates a second digitized signal in response to a comparison between the first derivative signal and a second threshold representing a second detection sensitivity. A mode selector selects as the output digitized signal one of the first digitized signal and a third digitized signal, the third digitized signal representing the first digitized signal modified by the second digitized signal.