Abstract: The invention is directed to an optical reader station for reading an object and a method of controlling an illumination source in the station for illuminating the object. The optical reader station comprises a mount for an optical reader and a stand with a surface for receiving the object, the optical reader includes an imager with an object field of view in which the object to be read is positioned. The station further includes a radiation source positioned within the object field of view and arranged to be obstructed by the object when the object is in position to be read. A detection mechanism, which is positioned to receive radiation from the radiation source when the radiation source is not obstructed by the object, deactivates the illumination source when radiation source radiation is detected.

Abstract: An output signal of an image sensor pixel, which substantially avoids fixed pattern noise contributed by the readout circuitry, is provided. The apparatus, which is used to provide an output signal that is a function of the difference between two sample signals VS1 and VS2, includes first and second capacitor elements that are coupled together at a common terminal. A reference voltage VREF is first applied to the capacitor elements, then a first sample signal VS1 from the image sensor pixel is applied to the first capacitor element producing a charge that is transferred to the second capacitor element. A second sample signal VS2 from the image sensor pixel is then applied to the first capacitor element producing a charge that is also transferred to the first capacitor element such that VO=VS2?VS1+VREF.

Abstract: Many electrical sensing devices include an array of transducer elements for converting external stimuli to electrical indications. Novel technologies to realize improvements in low power consumption, low noise, and analog output path which occupies minimal die area while maintaining certain data rates are disclosed. A two stage pipeline architecture of the invention in the analog output path maintains fast pixel rates with minimal ADC (analog digital converter) arrangement. A novel power supply and the use of differential amplifiers in connection with a black signal level as a reference voltage are also described.

Abstract: An improved optical code reading system and method that enhances the ability of a reader to locate a symbol within a field of view and enhances the error-correcting properties of the encoding scheme commonly used in 2D bar codes. The reader offsets the effects of damaged finder patterns and missing symbol perimeters and, thereafter, detects high-level symbol information such as the code type, symbol size, and the number of rows and columns in the symbol. The reader then identifies those missing portions of a damaged symbol and marks each missing data bit location with a predetermined indicator. A decoding algorithm then interprets the missing bit indicator as an error of known location (e.g., an “erasure”), thereby nearly doubling the error correcting strength of all bar codes employing the Reed-Solomon error correction scheme.

Abstract: A method and apparatus for testing an image sensor array such as a C-MOS imager which has sensing circuits arranged in rows and columns and wherein the sensing circuits include photosensitive devices is described. A reset voltage is applied to the photosensitive device in each of the sensor circuits such that at least adjacent circuits are reset to different voltage levels. The voltage on each photosensitive device is detected and compared to an expected level to determine if and where any faults may exist in the sensing circuits or lines in the array. A different reset voltage may be applied to each of the sensor circuits, however in one embodiment, a supply with only two voltage levels may be used. One voltage level is applied to every second column to provide a supply voltage to the photosensitive devices and to every second row to generate a reset enable signal for the photosensitive devices.

Abstract: This invention is directed to a method and apparatus for determining the level of ambient light impinging on a selected number of pixels in an imaging array where each pixel includes a photodiode. The ambient light may be determined by resetting the pixels in the array and by detecting current flow through the photodiodes in a selected number of the pixels as they are being reset. Alternately, the ambient light may be determined by resetting a selected number of the pixels in the array and by detecting current flow through the photodiodes in the selected number of the pixels as they are being reset. The photodiodes are reset by applying a reverse bias voltage across them and the current flow is detected by measuring the current flow through a resistance in parallel to the selected photodiodes. The selected number of pixels may be divided into one or more groups each having at least one pixel, and the pixels in each group may be arranged in specific patterns within the array.