PLANAR LASER ILLUMINATION AND IMAGING (PLIIM) DEVICE EMPLOYING A LINEAR IMAGE DETECTION ARRAY HAVING VERTICALLY-ELONGATED IMAGE DETECTION ELEMENTS, WHEREIN THE HEIGHT OF THE VERTICALLY-ELONGATED IMAGE DETECTION ELEMENTS AND THE F/# PARAMETER OF THE IMAGE FORMATION OPTICS ARE CONFIGURED TO REDUCE SPECKLE-PATTERN NOISE POWER THROUGH SPATIAL-AVERAGING OF DETECTED SPECKLE-NOISE PATTERNS

摘要

A planar laser illumination and imaging (PLIIM) based device a linear image formation and detection (IFD) module characterized by an F/# parameter mounted on a support platform. The IFD module has a linear image detection array with vertically elongated image detection elements and image formation optics having a field of view (FOV) projected through the light transmission window into an illumination and imaging field external to the hand-supportable housing and in which an object is presented for illumination and imaging. Each vertically-elongated image detection element having a height dimension (H) that is substantially greater than the width dimension (W) thereof. A pair of planar laser illumination arrays (PLIAs) is mounted within the hand-supportable housing and arranged on opposite sides of linear image formation and detection module. Each PLIA includes a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a composite planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of the FOV. Each PLIM includes a laser diode and beam focusing and diverging optics for producing one PLIB component. For a given wavelength of planar laser illumination, the height dimension (H) of each image detection element is selected to provide the largest possible spatial averaging area, while the F/# parameter of the linear IFD module is selected to provide the smallest possible average speckle noise pattern size along the height dimension of vertically-elongated image detection elements so that more individual speckle noise patterns can occur along the height dimension of each vertically-elongated image detection element in the linear IFD module. A series of linear images of object are sequentially detected by the linear IFD module as the object moves past the hand-supportable housing, so that the series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of the object. The level of speckle noise power observed at the linear image detection array is reduced through the spatial averaging of individual speckle noise patterns occurring along the height dimension of the image detection elements.