1. A method of illuminating objects during digital image capture operations by adaptively mixing visible and invisible spectral illumination energy at POS environments to form and detect digital images of objects at POS environments with sufficiently high image contrast and quality, said method comprising the steps of: (a) at POS environment, providing a digital image capture and processing system having a system housing with an imaging window, and an area-type illumination and imaging station disposed within said system housing, for projecting a coextensive area-type illumination and imaging field (i.e. zone) through said imaging window into a 3D imaging volume during object illumination and imaging operations, wherein said area-type illumination and imaging station includes (i) an image formation and detection (IFD) subsystem having an area-type image sensing array and optics providing a field of view (FOV) on the image sensing array and extending into said 3D imaging volume, (ii) an illumination subsystem having an array of visible LEDs and an array of infrared (IR) LEDs, (iii) an illumination control subsystem for controlling said illumination subsystem, (iv) an image capturing and buffering subsystem for capturing and buffering digital images of the illuminated object detected by said image sensing array, and (v) a digital image processing subsystem for processing said captured and buffered digital images, and (vi) an automatic object motion detection subsystem for automatically detecting motion of objects within said 3D imaging volume; (b) moving the object through said 3D imaging volume, and said automatic object motion detection subsystem automatically detecting the motion of said object, and generating signals indicative of said detected object motion; (c) in response to said generated signals, said illumination subsystem automatically producing a first field of visible illumination from said array of visible LEDs, simultaneously with a second field of invisible illumination from said array of infrared (IR) LEDs, whereby said first and second fields of illumination spatially overlap and intermix with each other and are substantially coextensive with said FOV, as said illumination control subsystem controls the relative power ratio (VIS/IR) of said fields of visible illumination and invisible illumination, and said image formation and detection subsystem forms and detects one or more digital images of said illuminated object, during said object illumination and imaging operation; (d) said image sensing array detecting digital images of the illuminated object during object illumination operations; (e) said image capturing and buffering subsystem capturing and buffering digital images of the illuminated object, detected by said image sensing array; and (f) said digital image processing subsystem automatically processing said buffered digital images so as to read one or more 1D and/or 2D code symbols graphically represented in said digital images.