| 摘要 |
A system for detecting image light intensity reflected off an object in a digital imaging-based bar code symbol reading device, said system comprising: an image formation subsystem having image formation optics for producing a field of view (FOV) upon a beam splitter, whereby the beam splitter has a surface of a known reflection/transmission ratio and reflects the FOV upon an object to be imaged; an illumination array subsystem for producing a field of illumination upon the object within the FOV during an image capture mode; an image detection subsystem having an area-type sensing array for detecting image light, wherein image light is reflected off the object and upon the beam splitter resulting in a portion of the image light being reflected towards the area-type sensing array during illumination operations in an image capture mode; a photodiode for detecting image light intensity, wherein image light is reflected off the object and upon the beam splitter resulting in a portion of the image light being transmitted through the beam splitter and focused upon said photodiode for subsequent processing by an automatic light exposure measurement and illumination control subsystem, whereby said automatic light exposure measurement and illumination control subsystem controls illumination intensity produced by said illumination array subsystem; and a system control subsystem for activating and controlling said subsystem components described above.
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