Camera with improved illuminator

Abstract

An illumination and imaging system is provided with a co-axial illuminator that does not include a beamsplitter. The co-axial illuminator achieves efficiencies substantially in excess of those achieved with a beamsplitter. In one aspect, an optical stop is used to reflect illumination upon a target. The optical stop includes an aperture allowing light reflected from the target to pass to a detector. The aperture of the stop has an asymmetrical feature that facilitates operation on specular targets.

What is claimed is:  
     
         1 . An illumination and imaging system for acquiring an image of an illuminated target of interest, system comprising: 
 a detector for receiving light and providing an electrical representation of an image;    an optical system optically coupled to the detector;    a stop disposed within the optical system and having an aperture for passing a portion of the light therethrough, the stop having an asymmetrical feature about an optical axis of the stop; and    a light source mounted between the target and the stop, the light source shining light substantially normally onto a surface of the stop, wherein light reflected from the surface of the stop onto the target forms light received at the detector.    
     
     
         2 . The system of  claim 1 , wherein the stop is formed of stainless steel.  
     
     
         3 . The system of  claim 1 , wherein the stop includes a diffuse surface.  
     
     
         4 . The system of  claim 1 , wherein the stop is coated with diffuse reflective material.  
     
     
         5 . The system of  claim 1 , and further comprising a plurality of additional light sources mounted substantially coplanar with the light source.  
     
     
         6 . The system of  claim 1 , wherein the light source includes a Light Emitting Diode.  
     
     
         7 . The system of  claim 1 , and further comprising a plurality of additional light source disposed to shine light substantially normally with respect to the surface of the stop.  
     
     
         8 . The system of  claim 1 , wherein the telecentric optical system includes a first lens cell positioned between the detector and the stop.  
     
     
         9 . The system of  claim 8 , and further comprising a baffle positioned between the first lens cell and the stop.  
     
     
         10 . The system of  claim 9 , and further comprising at least one additional baffle positioned between the baffle and the stop.  
     
     
         11 . The system of  claim 1 , wherein the stop and the light source are enclosed within an enclosure having a reflective interior.  
     
     
         12 . The system of  claim 11 , wherein the enclosure is cylindrically shaped.  
     
     
         13 . The system of  claim 1 , wherein the detector is a CCD array.  
     
     
         14 . The system of  claim 1 , wherein the light source is positioned within the telecentric optical system.  
     
     
         15 . The system of  claim 1 , and further comprising a plurality of additional tangs extending into the aperture and arranged asymmetrically about the aperture.  
     
     
         16 . The system of  claim 1 , wherein the optical system is telecentric in object space.  
     
     
         17 . The system of  claim 1 , and further comprising at least one tang extending into the aperture and arranged asymmetrically about the aperture.  
     
     
         18 . An illuminator comprising: 
 a enclosure having an optical axis passing therethrough;    a stop disposed within the enclosure, the stop having a reflective surface and an aperture, wherein at least one tang extends into the aperture; and    at least one light source disposed within the enclosure and adapted to direct light toward the reflective surface substantially normally to the reflective surface.    
     
     
         19 . An optical stop for use with an illuminator, the stop having an aperture alignable with an optical axis of the illuminator, the aperture having a feature therein arranged asymmetrically within the aperture.