Abstract: An optical reader includes targeting illuminators (e.g., LEDs) which generate a predetermined illumination pattern upon a target. The optical reader captures an image of the target and processes the captured image to determine whether the target is off-pitch or skewed, by analyzing the appearance and characteristics of the predetermined illumination pattern. The illumination pattern may consist of two identical triangles adjacently located but slightly separated so as to cause the pattern to be symmetrical when the target is at perfect alignment, but having shifting characteristics when the target is off-pitch or skewed. The optical reader may use the knowledge of pitch and skew to adjust the captured image. Triggerless operation of the optical reader is provided by placing the optical reader in a cradle and stand having a base with a known target printed on or affixed thereto, within the viewpath of the optical reader.

Abstract: A multi-function optical reader comprises an photosensor, such as a charge-device (CCD), and signal conditioning and processing circuitry including separate channels for handling data in different formats. A bar code processing channel digitizes the scan signal according to light and dark features using a first-derivative technique, and an OMR processing channel uses an adaptive threshold to adapt to different light conditions and provide a boundary line for digitizing light and dark features of the target scan line. A feature measurement circuit measures the widths of the light and dark regions as derived by the separate processing channels, and provides the feature measurements to a decoding system or host terminal processor. The scan rate of the optical reader can be adjusted according to the data format to be read or the level of ambient light, to avoid saturation. The optical reader can provide multiple depth-of-field zones, both internal and external to an optical reader housing.

Abstract: A multi-function optical reader comprises an photosensor, such as a charge-device (CCD), and signal conditioning and processing circuitry including separate channels for handling data in different formats. A bar code processing channel digitizes the scan signal according to light and dark features using a first-derivative technique, and an OMR processing channel uses an adaptive threshold to adapt to different light conditions and provide a boundary line for digitizing light and dark features of the target scan line. A feature measurement circuit measures the widths of the light and dark regions as derived by the separate processing channels, and provides the feature measurements to a decoding system or host terminal processor. The scan rate of the optical reader can be adjusted according to the data format to be read or the level of ambient light, to avoid saturation. The optical reader can provide multiple depth-of-field zones, both internal and external to an optical reader housing.