Hand-supportable planar laser illumination and imaging (PLIIM) device employing a pair of linear laser diode arrays mounted about a linear image detection array, for illuminating an object to be imaged with a plurality of optically-combined spatially-incoherent planar laser illumination beams (PLIBS) and reducing the speckle-pattern noise power in detected linear images by temporally averaging detected speckle-noise patterns during the photo-integration time period of said linear image detection array

摘要

A hand-supportable linear-type planar laser illumination and imaging (PLIIM) based device comprising a linear image formation and detection (IFD) module having a linear array of image detection elements and also image formation optics having a field of view (FOV) focusing a linear image of an object onto the linear array of image detection elements. A pair of planar laser illumination arrays (PLIAs) is arranged on opposite sides of the linear image formation and detection module, and produces a plurality of spatially-incoherent planar laser illumination beam (PLIB) components that are optically combined with respect to other PLIB components so as to produce a composite planar laser illumination beam (PLIB) that is arranged in a coplanar relationship with at least a portion of the FOV. Each PLIA includes a plurality of planar laser illumination modules (PLIMs). Each PLIM includes a laser diode and beam focusing and diverging optics for producing one spatially-incoherent PLIB component. The composite PLIB produces a number of substantially different individual speckle noise patterns at the linear array of image detection elements during the photo-integration time period thereof. The speckle noise power observed at the linear array of image detection elements is reduced through temporal averaging of the individual speckle noise patterns during the photo-integration time period. By virtue of the present invention, it is now possible to use visible laser diodes (VLDs) to produce speckle-reduced images of objects suitable for OCR processing, while enjoying improved working distances offered by planar laser illumination techniques.