Abstract: Bar-code data is read in the presence of noise. An analog output signal from a bar-code sensor has amplitude variations dependent upon the presence and absence of bars as well as upon differences in backgrounds upon which the bars are printed. The output signal is normalized to minimize variations therein, and the normalized signal in turn is converted to a digital signal at a sample interval small compared to the period of the known waveform. An expected response to each bar is of a known waveform. A digital reference set is stored which represents products formed by multiplying each quantization level of the digital signal by each sample of the known waveform taken at the sample interval. For each sample interval along the output signal, members of the reference set are selected dependent upon the sample interval of the known waveform and the corresponding amplitude of the digital signal, and summed to form one point of a correlation output function.

Abstract: An improved magnetic image character reading system which produces high signal levels, eliminates dead spots between sample tracks for full resolution. Two sets of read heads are positioned in a spaced apart, staggered arrangement such that one set is adjacent the other with elements of the first set staggered to overlap the tracks read by the second set. Scanned signals generated while passing magnetized characters first past one set and then past the second set of heads are combined after delay of the signal generated by the first set of heads to compensate for spacing between the sets of heads.

Abstract: Variations in scan rate and in position of a character within a field resulting from positional inaccuracies caused by use of a hand-held scanning device and/or loosely constrained document printing mechanisms and techniques are accommodated by sweeping a two-dimensional sensing array of about one character width and several character heights horizontally along a line across the field and applying a matrix of output signals resulting from each character to a recognition unit. Each set of signals is shifted vertically through the recognition unit at a rate such that all cells of the array are scanned in an interval required for movement of the field on the array of less than one resolution cell. Character recognition is attempted for each one-cell-height increment that the set is vertically shifted. A recognition output signal is produced when a character in the shifted set is brought into registration with a set of inputs leading to the recognition unit.

Abstract: Video signals generated by reading bar coded documents are transformed into pulses uniformly truncated in amplitude and having transitions only at points corresponding to change in sign of the slope of the adjusted video signals. The pulses are utilized to control the state of an output device depending upon whether the integral of any of the truncated pulses exceeds a reference level.

Abstract: Optically reading and processing alphanumeric data using a hand-held wand by passing a two-dimensional array of photosensitive elements horizontally along a line of data to be read. An optical image of the data is focused upon the array to produce digitized outputs which are thresholded to produce a one bit binary code indicating black cells and white cells. A subset of the binary quantities are combined in terms of black segments and white voids to form a plurality of character images while simulating vertical movement of the subset with character recognition attempted upon each simulated increment of vertical movement.

Abstract: A transport system moves documents beneath a self-scanned photocell array extending substantially the entire width of a page. The output data from the photocells is scanned via a plurality of channels, amplified, multiplexed, and converted to a digital format. The digital data is then processed to compensate for fixed pattern errors characteristic of the photocell array and for scan pattern error. The corrected digital data is quantized for character thresholding and input to a recirculating memory. Line-tracking circuitry monitors the location of individual lines of character data within the recirculating memory and gates a complete line of character data into one of two storage registers. While data is input to one register, the contents of the other register is output to character recognition circuitry.

Abstract: A redundant character recognition system which minimizes both read failures and ambiguities caused by conflicting read signals by merging character recognition signals from MICR, OCR and Bar-Code read heads to produce a single data stream for automatic sorting of a constant velocity train of documents. In the event the MICR and OCR readers are unable to identify a character image, a Bar-Code reader is used to supplement MICR/OCR data by replacing MICR data field rejects with bar-code data field recognition signals. When rejects are generated from both the MICR and bar-code data fields, only self-checking fields within the bar-code data field are merged upon a successful self-check test being performed. If self-checking errors occur, the MICR read data is restored.

Abstract: An optical data reader and processor utilizing a two dimensional array of photosensitive elements operated at a high frame rate; a shift register of one character width, and greater than one character height to store the binary representation of the character image; unique black/white threshold detection and character recognition logical circuitry; and timing means to overcome inaccuracies arising from the loosely constrained movement of a hand-held scanning device.

Abstract: A method and system for improving the signal-to-noise ratio in an automatic electro-optical reader of bar codes, wherein fluorescent ink bars arranged in coded configurations on a document are excited by a narrow band of visible radiation in the blue region of the electromagnetic spectrum, and an adjacent but not overlapping visible red region of the spectrum emanating from the ink bars is optically focused onto a light sensitive detector.

Abstract: A document transport including an endless belt driven by a pair of logic controlled servo motors which precisely move a document from a feeding station through a scanning station and into a stacking station. As documents are passed through the scanning station, images of the characters thereon are projected by a scanner onto a single columnar retina. The scanner includes a single shaft which is repetitively rotated through a preselected arc by a logic controlled servo motor synchronized with the transport control system. An illumination mirror is mounted on one end of the shaft and an image mirror is mounted on the other so that illumination from a lamp is scanned across the characters to be read while the illuminated images are reflected from the image mirror onto the retina.