Imaging system utilizing both diffuse and specular reflection characteristics

In a cigarette manufacturing device comprising a continuous roll of cigarette paper, a plurality of transfer rollers for conveying said cigarette paper through said cigarette manufacturing device, a glue application station for applying glue to only a portion of a surface of said cigarette paper, and a rolling station for rolling said cigarette paper, with a filter and pre-rolled tobacco components into a finished cigarette product;

• the improvement wherein said cigarette manufacturing device is provided with an imaging system for imaging a surface of said cigarette paper following the application of glue thereto, said imaging system comprising a source of incident light for supplying co-axial diffuse light, along an observation axis, to said cigarette paper, following the application of glue thereto, whereby both a portion of said cigarette paper having glue and a portion of said cigarette paper remaining unglued are supplied with co-axial diffuse light, and said glued portion reflecting a substantial portion of the supplied co-axial diffuse light back along said observation axis while said unglued portion of said cigarette paper, having diffuse reflection characteristics, scatters the supplied co-axial diffuse light in a plurality of different reflective directions so that only a minor portion of the supplied co-axial diffuse light is reflected back along said observation axis;
• an imaging device for receiving the reflected light representing an optical image of said cigarette paper, said imaging device being spaced a sufficient distance from said cigarette paper so that each said portion of said cigarette paper containing glue is perceived by said imaging device as being of a relatively bright intensity while each said portion of said cigarette paper which is unglued is perceived by said imaging device as being of a relatively dark intensity, in comparison to said glued portions, whereby the inspection of the application of glue to said cigarette paper is achieved.

A method of imaging a desired generally planar surface area of an object, being located within a field of view of an imaging system, having a first area with specular reflection characteristics and a second area with diffuse reflection characteristics which are different from said specular reflection characteristics, said method comprising the steps of:

• supplying a source of incident light of continuous co-axial diffuse light, along an observation axis, to said desired surface area of said object to be observed which is located within said field of view whereby the entire desired surface area to be observed, including both said first and second areas, is supplied with said co-axial diffuse light;
• reflecting a substantial portion of said supplied co-axial diffuse light back, via said first area having said specular reflection characteristics, along said observation axis;
• scattering said supplied co-axial diffuse light in a variety of different reflection directions, via said second area having said diffuse reflection characteristics, so that only a portion of said supplied co-axial diffuse light is reflected back along said observation axis;
• receiving the reflected light, representing an optical image of said surface of said object to be observed, with an imaging device;
• and
• locating said imaging device along said observation axis a sufficient distance from said surface of said object so that said imaging device is able to perceive a reflection from the entire desired surface area to be observed as well as detect a difference in reflection intensity between said first area and said second area and process said reflection of at least said first area, having said specular reflection characteristics, as being relatively bright while perceive said reflection of at least said second area, having said diffuse reflection characteristics, as being relatively dark, in comparison to said first area, for discerning a characteristic of at least one of said first and said second areas;
• and
• supplying said source of incident light through at least one aperture, provided in said source of incident light, and determining a size of said at least one aperture according to the formula:
• Aperture Size=(2P+A)-((P+A)(Z-LZ) /Z)
• Where:
• A=an entrance pupil diameter of a lens of said imaging device;
• P=a maximum width of said object to be observed;
• Z=a distance between the lens and a top surface of said object to be observed, measured along said observation axis;
• and
• LZ=a distance from a too of a housing containing said source of incident light to the top of said object to be observed, measured along said observation axis.

An imaging system with a desired field of view, for imaging a desired generally planar surface of an object, being located within said field of view, having a first area with specular reflection characteristics and a second area with diffuse reflection characteristics which are different from said specular reflection characteristics, said imaging system comprising:

• a source of incident light, for supplying continuous co-axial diffuse light along an observation axis, to said desired surface of said object to be observed which is located within said field of view whereby the entire desired generally planar surface to be observed, including both said first and second areas, is supplied with said co-axial diffuse light, and said first area, having said specular reflection characteristics, reflecting a substantial portion of said supplied co-axial diffuse light back along said observation axis while said second area, having said diffuse reflection characteristics, scattering said supplied co-axial diffuse light in a variety of different reflection directions so that at least a portion of said supplied co-axial diffuse light is reflected back along said observation axis;
• an imaging device for receiving the reflected light representing an optical image of said surface of said object to be observed, said imaging device being located along said observation axis and being spaced a sufficient distance from said surface of said object so that said imaging device is able to perceive a reflection from the entire desired generally planar surface to be observed as well as detect a difference in reflection intensity between said first area and said second area and process said reflection of at least said first area, having said specular reflection characteristics, as being relatively bright, while perceiving said reflection of at least said second area, having said diffuse reflection characteristics, as being relatively dark, in comparison to said first area, for discerning a characteristic of at least one of said first and said second areas;
• and
• said source of incident light is supplied through at least one aperture, provided in said source of incident light, and said at least one aperture has a size which is determined according to the formula:
• Aperture Size=(2P+A)-((P+A)(Z-LZ)/Z))
• Where:
• A=an entrance pupil diameter of a lens of said imaging device;
• P=a maximum width of said object to be observed;
• Z=a distance between the lens and a top surface of said object to be observed, measured along said observation axis;
• and
• LZ=a distance from a top of a housing containing said source of incident light to the top of said object to be observed, measured along said observation axis.

An imaging system with a desired field of view, for imaging a desired generally planar surface of an object, being located within said field of view, having a first area with specular reflection characteristics and a second area with diffuse reflection characteristics which are different from said specular reflection characteristics, said imaging system comprising:

• a source of incident light, for supplying continuous co-axial diffuse light along an observation axis, to said desired surface of said object to be observed which is located within said field of view whereby the entire desired generally planar surface to be observed, including both said first and second areas, is supplied with said co-axial diffuse light, and said first area, having said specular reflection characteristics, reflecting a substantial portion of said supplied co-axial diffuse light back along said observation axis while said second area, having said diffuse reflection characteristics, scattering said supplied co-axial diffuse light in a variety of different reflection directions so that at least a portion of said supplied co-axial diffuse light is reflected back along said observation axis;
• an imaging device for receiving the reflected light representing an optical image of said surface of said object to be observed, said imaging device being located along said observation axis and being spaced a sufficient distance from said surface of said object so that said imaging device is able to perceive a reflection from the entire desired generally planar surface to be observed as well as detect a difference in reflection intensity between said first area and said second area and process said reflection of at least said first area, having said specular reflection characteristics, as being relatively bright, while perceiving said reflection of at least said second area, having said diffuse reflection characteristics, as being relatively dark, in comparison to said first area, for discerning a characteristic of at least one of said first and said second areas;
• and
• a light barrier encasing said observation axis and extending from said source of incident light to a location adjacent said surface of said object to be observed, to prevent surrounding environmental light from affecting the imaging of the object to be observed by said imaging system;
• and an inwardly facing surface of said barrier being provided with a light absorbing material to absorb light contacting said inwardly facing surface of said barrier.