Patent ID: 7472831

Claim:
An image formation system for detecting image light intensity reflected off an object placed in a field of view of a digital imaging based bar code symbol reading device, said system comprising: an illumination array subsystem for producing a field of illumination upon said object during an image capture mode of said digital imaging based bar code symbol reading device an image detection subsystem having an area type sensing array for detecting image light which is reflected off said object within the field of view of said digital imaging based bar code symbol reading device; a photodiode for detecting image light intensity which is reflected off said object within said field of view digital imaging based bar code symbol reading device for subsequent processing by an automatic light exposure measurement and illumination control subsystem; a beam splitter having a surface of a known reflection/transmission ratio and positioned within said field of view of said digital imaging based bar code symbol reading device whereby when said image light is reflected off said object in said field of view and upon said beam splitter a portion of said reflected image light is directed towards said area type sensing array during illumination operations in an image capture mode and a portion of said reflected image light is transmitted through said beam splitter and focused upon said photodiode, whereby said automatic light exposure measurement and illumination control subsystem controls at least one of the intensity or duration of illumination produced by said illumination array subsystem; and a system control subsystem for activating and controlling said subsystem components described above.