Abstract: A visual inspection apparatus can include a handset, elongated inspection tube extending from the handset and a light source bank disposed within a hand held housing of the handset. For reduction of heat energy radiating from the light source bank, the apparatus can include one or more of a thermal control system and a particularly designed heat sink assembly.

Abstract: A visual inspection apparatus can include a handset, elongated inspection tube extending from the handset and a light source bank disposed within a hand held housing of the handset. For reduction of heat energy radiating from the light source bank, the apparatus can include one or more of a thermal control system and a particularly designed heat sink assembly.

Abstract: The present invention is directed to a method for reading a bar code symbol with an optical reader. The method includes the step of scanning the bar code symbol to obtain a plurality of scan lines. Each of the plurality of scan lines includes a linear array of N-pixel values. Adjacent pixels in the linear array of N-pixel values are separated by a sample separation distance. A reconstructed scan line is generated that interleaves the N-pixel values from selected scan lines of the plurality of scan lines. A reconstructed pixel sample separation distance of adjacent interleaved pixels is an integer fraction of the pixel sample separation distance.

Abstract: An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the illumination level at the image sensor. A window detecting circuit samples the illumination signal during a predetermined part of each scan to determine whether the illumination signal is within the window, has exited the widow, or has re-entered the window. Exposure control circuitry uses the output of the window detecting circuit to control which of a plurality of the subdivisions of the exposure control range of the image sensor will be used. Changes in exposure time are made only between adjacent subdivisions of the exposure control range. Together with a predetermined hysteresis between the exit and re-entry thresholds of the window, the latter changes stabilize the operation of the reader by reducing exposure control “hunting”.

Abstract: A method and apparatus for reading and decoding one-dimensional (1D) bar code symbols. A 1D bar code symbol is imaged by an optical assembly which includes a cubic phase mask that causes the optical transfer function of the optical assembly to remain approximately constant over a range of distances between the apparatus and the symbol to be read. An electrical representation of the resulting image is converted to a smoothly varying analog image signal. A transition identifying circuit processes the analog image signal, without first applying a recovery function that takes into account the effect of the phase mask, and generates a binary signal which is used to decode the symbol.

Abstract: A bar code reader is provided which can read bar code symbols of varying contrast, from high to medium to low contrast. The bar code reader includes a digitizing circuit which digitizes an analog signal representing the reflectance function of a scanned bar code by comparing the analog signal to a threshold signal. In the present invention, the threshold signal is switchable between a first state wherein the threshold signal is a standard threshold signal suitable for digitizing analog signals representing medium to high contrast bar code symbols and a second state wherein the threshold signal is a non-standard threshold signal suitable for digitizing analog signals representing low contrast bar code symbols. In one embodiment of the invention, the threshold signal is manually adjustable.

Abstract: An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the time averaged value of the illumination level at the image sensor. A window detecting circuit periodically samples the illumination signal to determine if that signal is or is not within a window of acceptability. Exposure period determining circuitry uses the output of the window detecting circuit to upwardly or downwardly adjust the value of a control variable as necessary to cause the illumination signal to approach, enter and remain within the window of acceptability.