An imaging system includes an illumination unit and a sensor unit disposed on a printed circuit board. The illumination unit includes a diode laser source inside an illumination housing. The sensor unit includes an image sensor having a pixel array and a lens barrel mounted on the image sensor with an adhesive, and an optical fiber coupled between the illumination housing and image sensor. The optical fiber is configured to collect a portion of light from the interior of the illumination housing that is emitted by the diode laser source and direct the portion of light to a corner of the pixel array of the image sensor that is located outside the lens barrel.