Abstract: A system and method for reading a two-dimensional image, and for comparing the two-dimensional image to stored data representative of a known image. The optical scanning device comprises a sensor for capturing the two-dimensional image, which sensor includes an LED array for projecting an emitted light towards the two-dimensional image. The sensor also includes a lens disposed forward of the LED array for focussing the emitted light and thereby framing the two-dimensional image. The sensor further includes an optical assembly for focussing an ambient light reflected from the framed two-dimensional image. And the sensor includes a CMOS (or CCD) detector for detecting the focussed ambient light, the CMOS detector including a photodiode array for sensing the focussed ambient light and a processor for processing the ambient light to obtain an electrical image signal. The optical scanning device also compresses the electrical image signal.

Abstract: Methods are provided to assist in selection of appropriate optical components for optimizing performance of the optical scanner for reading one-, two- and three-dimensional optically encoded information at a wide range of field depths and angles. The optical components are fixed in position relative to each other so that no position adjustments are required to obtain a reading at a desired distance once the optical components are optimized. Among the parameters that are considered are LEDs for emitting light within specific wavelength ranges, optical filters, lens focal lengths, magnification, etc. The Fourier transform of an input square wave signal generated by light reflected from a bar code is used to generate the appropriate resolution requirements. Selection of appropriate optical components is dependent upon the intended operation of the scanner. For example, depth of field is considered, as is scan angle and density of the code to be read.

Abstract: A system and method for reading a two-dimensional barcode symbology. The two-dimensional barcode symbology has lines of data, each of the lines having several bars and spaces, each of the bars and spaces having a width. The method comprises scanning one of the lines using a CCD optical scanning head to obtain a scanned line. The bars and spaces in the scanned line are then converted into element time intervals, each of the element time intervals corresponding to, and representing the width of, one of the bars and spaces, thereby obtaining a converted line. For the converted line, a predefined prefix message, followed by the element time intervals, followed by a predefined suffix message are then output from the CCD optical scanning head to a processor.

Abstract: The optical scanner has an optical scanning head with LED light sources, focusing and receiving optics and a CCD detector array all mounted on a printed circuit board. This assembly, along with a storage buffer and a decoder is contained within a small housing which is attached on its lower side to a semi-glove which the user can wear on the back of his or her hand. The automatic sensing feature of the invention provides hands-free operation by automatically and periodically testing for the presence of a bar code in the scanner's field of view. If the presence of a bar code is detected, the scanner is placed in active mode. When the scanner is not in use, the scanner is powered down to conserve energy.

Abstract: The optical scanning head comprises two or more LEDs which are oriented to emit light at different angles so that a fan of light is created. A "dark room" encloses the LEDs, a lens assembly, and the spacing between the lens assembly and the detector, a linear CCD array. The portion of the dark room that extends between the lens assembly and the detector has a plurality of baffles formed therein to capture scattered light, preventing this scattered light from becoming noise at the detector. The lens assembly includes, along with a plurality of focusing lenses, a combination of a generally elliptical aperture, or "cat's eye, and a rectangular obscuration. The combination prevents the central lobe of the Airy disk generated by the incoming light from being transmitted to the detector. This results in the incoming information being carried in the outer lobes or rings, increasing the angular separation of the lines of the bar code.