Patent ID: 9004363
Filing Date: 2015-04-14
Classification: G06K

Abstract:
1. An apparatus comprising: an illumination light source for generating illumination light; an imaging lens arrangement; an imaging sensor having photosensitive elements; a controller for controlling both the illumination light source and the imaging sensor; wherein the controller, the illumination light source, the imaging lens arrangement, and the imaging sensor are all deposited within the volume space of a solid rectangular having a height H, width W, and length L; a diffusive plate substantially perpendicular to the optical axis of the imaging lens arrangement and covering a side face of the solid rectangular, with the area enclosed by the boundary of the diffusive plate substantially equal to the area of the side face having the dimension of the height H and the width W, wherein the diffusive plate comprises a first opening to allow light enter the imaging lens arrangement through the first opening; wherein the photosensitive elements in the imaging sensor are configured to detect light from a target object within an imaging field of view through the imaging lens arrangement during a time period when the target object is illuminated by diffusive light from all of a front surface of the diffusive plate as light from the illumination light source is projected onto the diffusive plate; and an auxiliary diffusive plate detachably mounted outside the boundary of the diffusive plate, wherein the auxiliary diffusive plate is made of volume diffusion material and has two surfaces separated from each other by a distance that is less than one fifth (⅕) of both the height H and the width W of said volume space.