An optical scanning system is provided for producing a signal representative of a spatial distribution of indicia having different degrees of reflectivity to light, such as a bar code (14). The system includes an optical scanner (12) for scanning beam of light over the spatial distribution of indicia (14) and for producing an electrical signal corresponding to changes in the degree of reflectivity of the indicia. A digitizer (20), responsive to detections in a predetermined characteristic of the produced electrical signal is provided. The digitizer (20) converts the detections into digital words, such digital signals having a plurality of bits. The digitizer includes a timing generation circuit (42) for producing a pulse in response to each one of the detections with a time duration representative of the degree of reflectivity of the indicia as the beam of light. A decoder converts the time duration of the pulse into the digital word having a plurality of bits. An enhancement filter (30) is also disclosed. The enhancement filter (30) modifies pulses produced by a differentiator circuit (24) used in the scanner. Such modification includes increasing the rise time, and peak level of, the pulses produced by the differentiator circuit (24).
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 08/651,613, filed May 22, 1996, now allowed. This application is a continuation of U.S. patent application Ser. No. 08/335,001, filed Nov. 9, 1994, now U.S. Pat. No. 6,082,621, and U.S. patent application Ser. No. 08/454,830, filed May 31, 1995, which issued as U.S. Pat. No. 5,734,152; and U.S. patent application Ser. No. 08/455,216, filed May 31, 1995, now pending. This application is also a continuation of U.S. patent application Ser. No. 08/347,597 filed Nov. 30, 1994 U.S. Pat. No. 5,449,893 which is a continuation of Ser. No. 08/153,638 filed Nov. 17, 1993 now abandoned; and a patent application filed concurrently herewith entitled "Method of Scanning Indicia Using Selective Sampling", inventors David-Goren, Raj Bridgelall, and Edward Barkin; U.S. patent application Ser. No. 08/335,001 filed Nov. 9, 1994 U.S. Pat. No. 6,082,621; and, U.S. patent application No. 07/862,471, filed Apr. 2, 1992, now U.S. Pat. No. 5,302,813 issued Apr. 12, 1994 which related to U.S. Patent application filed Apr. 4, 1992 all assigned to the same assignee as the present invention, the subject matter all of which is incorporated herein by reference, the benefit of the filing dates of one, or more, of such patent applications being claimed herein to the fullest extent allowed under the provisions of 35 U.S.C. 120.
Systems better detect transitions in a binary optical code signal and thus better detect edges in binary optical codes, such as bar codes. The optical code signal imperfectly indicates perceived regions of relatively dark and light areas arranged in an alternating pattern as part of an optical code. That signal is differentiated to form a first derivative. Due to various non-ideal conditions, the first derivative may have a series of successive local peaks of the same polarity. Peaks in the series having a peak value less than a previous peak value in the series are ignored, thereby resulting in a set of unignored peaks. From the unignored peaks in the series is chosen the one peak occurring last in order. According to the chosen peak, there is generated a signal more reliably indicating the true edge position between light and dark areas in the pattern.
Systems process an input signal, derived from a binary optical code, having a series of multiple successive local peaks of the same given polarity. The circuit comprises a peak detector, a node in the peak detector, and a set-reset flip-flop. The peak detector has an input receiving the input signal and produces an output that approximately tracks the input signal while it is sloping in the direction of the given polarity and that approximately holds near those local peaks having successively larger magnitude. A node in the peak detector has a voltage indicative of whether the peak detector is in a tracking or holding state. The set-reset flip-flop has a set input connected to the node, whereby the output of the flip-flop is high when the peak detector is in a tracking state. The circuit is useful for qualifying optical edges in a bar code.
The present invention provides a method of modifying the behavior of a modeled system from a graphical representation of the behavior of the system. Given a graphical representation of the behavior of a modeled system, one or more bounds may be selected for the behavior on the graphical representation. The necessary parameters for the modeled system are then determined for producing the desired behavior based on the selected bounds for the behavior.
In a multi-modal user interface, user inputs may be made in various different ways. For instance, the user might use a keyboard, a speech system, a vision system, a mouse or pen. Different inputs made by the user may be related and may have different significance. A processing system detects and resolves ambiguities and/or conflicts in inputs made by the user using the different input modes available.
