Back side plate illumination for biological growth plate scanner

Abstract

A biological growth plate scanner includes a multi-color illumination system that illuminates a biological growth plate with different illumination colors. A monochromatic image capture device captures images of the biological growth plate during illumination of the growth plate with each of the illumination colors. A processor combines the images to form a composite multi-color image, and/or individual components of the composite image, and analyzes the composite image to produce an analytical result such as a colony count or a presence/absence result. The biological growth plate scanner may include both front and back illumination components. The back illumination component may include a diffuser element disposed under the biological growth plate. The diffuser element receives light from one or more laterally disposed illumination sources, and distributes the light to illuminate a back side of the biological growth plate. The illumination sources in the front and back illumination components may take the form of sets of light emitting diodes (LEDs) that can be independently controlled by the processor.

1 . A device comprising: 
 an optical diffuser element; and    an illumination source oriented to direct light into the optical diffuser element, wherein the optical diffuser element directs the light toward a side of a biological growth plate.    
     
     
         2 . The device of  claim 1 , wherein the optical diffuser element defines a first major surface, a second major surface and two or more side surfaces, and the illumination source includes a plurality of illumination sources oriented to direct the light into the optical diffuser element via at least some of the side surfaces.  
     
     
         3 . The device of  claim 2 , wherein the illumination sources are oriented to direct light into the optical diffuser element via two of the side surfaces.  
     
     
         4 . The device of  claim 2 , wherein the optical diffuser element includes a diffusing material adjacent the first major surface, and a reflecting element adjacent the second major surface, and the optical diffusing material directs the light toward the side of the biological growth plate via the first major surface.  
     
     
         5 . The device of  claim 2 , wherein the optical diffuser element is movable to support and transport the biological growth plate to a scanning position for scanning of the biological growth plate.  
     
     
         6 . The device of  claim 5 , wherein the optical diffuser element is movable relative to the illumination sources between a position to receive the biological growth plate and the scanning position.  
     
     
         7 . The device of  claim 2 , wherein the optical diffuser element includes a diffusing film formed on the first major surface, and a reflecting film formed on the second major surface, and reflection of the light from the reflecting film causes the optical diffusing film to direct the light toward the side of the biological growth plate via the first major surface.  
     
     
         8 . The device of  claim 1 , wherein the illumination source selectively produces one or more different illumination colors, the device further comprising: 
 a monochromatic camera oriented to capture an image of the biological growth plate; and    a processor that controls the camera to capture one or more images of the biological growth plate during illumination with each of the different illumination colors.    
     
     
         9 . The device of  claim 8 , wherein the different illumination colors are red, green and blue, and the camera captures images of the biological growth plate during the red, green and blue illumination.  
     
     
         10 . The device of  claim 8 , wherein the processor controls the illumination sources to sequentially illuminate the biological growth plate with each of the different illumination colors, and to control an illumination duration for each of the different illumination colors.  
     
     
         11 . The device of  claim 1 , wherein the illumination source includes: 
 a set of red light emitting diodes to produce red illumination;    a set of green light emitting diodes to produce green illumination; and    a set of blue light emitting diodes to produce blue illumination.    
     
     
         12 . The device of  claim 11 , further comprising a processor to selectively control activation of the red, green and blue light emitting diodes according to illumination requirements of the biological growth plate.  
     
     
         13 . The device of  claim 1 , wherein the biological growth plate carries a biological agent in the group consisting of aerobic bacteria,  E. coli , coliform, enterobacteriaceae, yeast, mold,  Staphylococcus aureus , Listeria, and Campylobacter.  
     
     
         14 . The device of  claim 1 , wherein the biological growth plate is a thin film culture plate.  
     
     
         15 . The device of  claim 1 , wherein the optical diffuser element defines a first major surface, a second major surface and four side surfaces, and the illumination source includes a plurality of illumination sources oriented to direct the light into the optical diffuser element via at least two of the side surfaces, the device further comprising a reflective material formed adjacent at least one of the side surfaces.  
     
     
         16 . A method comprising directing light into an optical diffuser element to illuminate a side of a biological growth plate.  
     
     
         17 . The method of  claim 16 , wherein the optical diffuser element includes a first major surface, a second major surface and two or more side surfaces, the method further comprising directing the light into the optical diffuser element via at least some of the side surfaces.  
     
     
         18 . The method of  claim 17 , further comprising directing the light into the optical diffuser element via two of the side surfaces.  
     
     
         19 . The method of  claim 17 , wherein the optical diffuser element includes a diffusing material adjacent the first major surface, and a reflecting element adjacent the second major surface, and the optical diffusing material directs the light toward the side of the biological growth plate via the first major surface.  
     
     
         20 . The method of  claim 17 , further comprising moving the optical diffuser element to support and transport the biological growth plate to a scanning position for scanning of the biological growth plate.  
     
     
         21 . The method of  claim 20 , further comprising moving the optical diffuser element relative to the illumination sources between a position to receive the biological growth plate and the scanning position.  
     
     
         22 . The method of  claim 17 , wherein the optical diffuser element includes a diffusing film formed on the first major surface, and a reflecting film formed on the second major surface, and reflection of the light from the reflecting film causes the optical diffusing film to direct the light toward the back surface of the biological growth plate via the first major surface.  
     
     
         23 . The method of  claim 16 , further comprising: 
 selectively illuminating the side of the biological growth plate with one or more different illumination colors via the optical diffuser element; and    capturing one or more images of the biological growth plate with a camera during illumination with each of the different illumination colors.    
     
     
         24 . The method of  claim 23 , wherein the different illumination colors are red, green and blue, the method further comprising capturing images of the biological growth plate during the red, green and blue illumination.  
     
     
         25 . The method of  claim 23 , further comprising sequentially illuminating the biological growth plate with each of the different illumination colors, and controlling an illumination duration for each of the different illumination colors.  
     
     
         26 . The method of  claim 25 , further comprising producing the illumination colors with: 
 a set of red light emitting diodes to produce red illumination;    a set of green light emitting diodes to produce green illumination; and    a set of blue light emitting diodes to produce blue illumination.    
     
     
         27 . The method of  claim 26 , further comprising selectively controlling activation of the red, green and blue light emitting diodes according to illumination requirements of the biological growth plate.  
     
     
         28 . The method of  claim 16 , wherein the biological growth plate carries a biological agent in the group consisting of aerobic bacteria,  E. coli , coliform, enterobacteriaceae, yeast, mold,  Staphylococcus aureus , Listeria, and Campylobacter.  
     
     
         29 . The method of  claim 16 , wherein the biological growth plate is a thin film culture plate.  
     
     
         30 . A device comprising: 
 an optical diffuser element;    a first illumination source oriented to direct light into the optical diffuser element, wherein the optical diffuser element directs the light toward a first side of a biological growth plate;    a second illumination source oriented to direct light toward a second side of the biological growth plate; and    means for scanning the second side of the biological growth plate during illumination of the first and second sides by the optical diffuser element and the second illumination source.    
     
     
         31 . The device of  claim 30 , wherein the optical diffuser element includes a first major surface, a second major surface and two or more side surfaces, and the illumination source includes a plurality of illumination sources oriented to direct the light into the optical diffuser element via at least some of the side surfaces.  
     
     
         32 . The device of  claim 31 , wherein the illumination sources are oriented to direct light into the optical diffuser element via two of the side surfaces.  
     
     
         33 . The device of  claim 31 , wherein the optical diffuser element includes a diffusing material adjacent the first major surface, and a reflecting element adjacent the second major surface, and the optical diffusing material directs the light toward the side of the biological growth plate via the first major surface.  
     
     
         34 . The device of  claim 31 , wherein the optical diffuser element is movable to support and transport the biological growth plate to a scanning position for scanning of the biological growth plate.  
     
     
         35 . The device of  claim 31 , wherein the optical diffuser element includes a diffusing film formed on the first major surface, and a reflecting film formed on the second major surface, and reflection of the light from the reflecting film causes the optical diffusing film to direct the light toward the side of the biological growth plate via the first major surface.  
     
     
         36 . The device of  claim 30 , wherein the first and second illumination sources selectively produce one or more different illumination colors, and the scanning means includes a monochromatic camera oriented to capture an image of the biological growth plate, the device further comprising a processor that controls the camera to capture one or more images of the biological growth plate during illumination with each of the different illumination colors.  
     
     
         37 . The device of  claim 36 , wherein the different illumination colors are red, green and blue, and the camera captures images of the biological growth plate during the red, green and blue illumination.  
     
     
         38 . The device of  claim 36 , wherein the processor controls the illumination sources to sequentially illuminate the biological growth plate with each of the different illumination colors, and to control an illumination duration for each of the different illumination colors.  
     
     
         39 . The device of  claim 30 , wherein each of the first and second illumination sources includes: 
 a set of red light emitting diodes to produce red illumination;    a set of green light emitting diodes to produce green illumination; and    a set of blue light emitting diodes to produce blue illumination.    
     
     
         40 . The device of  claim 39 , further comprising a processor to selectively control activation of the red, green and blue light emitting diodes according to illumination requirements of the biological growth plate.  
     
     
         41 . The device of  claim 30 , wherein the biological growth plate carries a biological agent in the group consisting of aerobic bacteria,  E. coli , coliform, enterobacteriaceae, yeast, mold,  Staphylococcus aureus , Listeria, and Campylobacter.  
     
     
         42 . The device of  claim 30 , wherein the biological growth plate is a thin film culture plate.  
     
     
         43 . The device of  claim 30 , wherein the optical diffuser element defines a first major surface, a second major surface and four side surfaces, and the illumination source includes a plurality of illumination sources oriented to direct the light into the optical diffuser element via at least two of the side surfaces, the device further comprising a reflective material formed adjacent at least one of the side surfaces.