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US 5,352,888 AGranted
Method and apparatus for detecting and utilizing frame fill information in a sorting machine having a background and a color sorting band of light
AssigneeESM International, Inc.
InventorJoel P. Childress
Life of this patent
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Abstract
Apparatus and method for measuring the reflectivity of a product for use in optical sorting machines that is insensitive to product size and orientation. The percentage reflectivity of a product passing a background is corrected by a frame fill factor, which is representative of the percentage of the viewing frame occupied by the product being sorted.
Claims23
A method of producing uniform amplitude signals for products of the same detected color in a product stream that passes through a color sorting machine regardless of the amount of respective frame fill occupied by such products, which comprises
- establishing a viewing frame through which light is reflected from the product stream,
- establishing a background which contrasts with the product stream,
- detecting the reflected light passing through the viewing frame at a plurality of pixel locations spanning the viewing frame on a line transverse to the axis of the reflected light through the viewing frame by using a detector at each pixel location,
- each detector that detects background produces an output signal at a level below a predetermined trip line output value and
- each detector that detects the presence of a product in the product stream produces an output signal above the predetermined trip line level,
- combining the output of the detectors to produce a frame fill percentage output for each detected product that is a percentage of the number of pixel locations that detect the presence of the product to the total number of pixels spanning the viewing frame,
- photodetecting for each product in a reflected color sorting band light passing through the viewing frame and producing a raw signal with an amplitude proportional to the total contrasting lightness of the product and background in the viewing frame, and
- dividing the photodetected raw signal with the frame fill percentage output to produce a photodetected corrected signal so that the same lightness of photodetected product will produce the same amplitude of signal regardless of frame fill.
5 more elements
A method of sorting homogeneous products in a product stream that passes through a color sorting machine and ejecting non-homogeneous products from the product stream, which comprises
- establishing a viewing frame through which light is reflected from the product stream,
- a background which contrasts with the product stream,
- detecting the reflected light passing through the viewing frame at a plurality of pixel locations spanning the viewing frame on a line transverse to the axis of the reflected light through the viewing frame by using a detector at each pixel location,
- each detector that detects background produces an output signal at a level below a first predetermined trip line output value and
- each detector that detects the presence of a product in the product stream produces an output signal above the first predetermined trip line level value,
- combining the output of the detectors to produce a frame fill for each detected product that is proportional to the number of pixel locations that detect the presence of the product,
- dividing the frame fill output that is proportional in duration to the number of pixel locations that detect the presence of the product by the total number of pixel locations spanning the viewing frame,
- photodetecting light in a reflected color sorting band for each product passing through the viewing frame and producing a raw signal with an amplitude proportional to the total reflectivity in the color sorting band of the product and background in the viewing frame,
- dividing the photodetected raw signal with the frame fill percentage output to produce a photodetected corrected signal so that the same color of photodetected product will produce the same amplitude of signal regardless of frame fill, and
- producing an ejection signal for non-homogeneous products when the corrected signal exceeds a second predetermined trip level value.
7 more elements
Apparatus for sorting homogeneous products in a product stream that passes through a color sorting machine and ejecting non-homogeneous products from the product stream, comprising
- at least one optical viewing assembly including
- a light for producing at least one reflected color sorting band of light from the products in the product stream,
- a background which contrasts with the product stream,
- a viewing frame through which reflected light from the products in the product stream passes, and
- a plurality of detectors of the reflected color sorting band at respective pixel locations spanning said viewing frame on a line transverse to the axis of the reflected light through the viewing frame,
- each detector that detects background produces an output signal at a level below a first predetermined trip line output value and
- each detector that detects the presence of a product in the product stream produces an output signal above the first predetermined trip line level value,
- output means for combining the output of the detectors to produce a frame fill output for each detected product that is proportional to the number of pixel locations that detect the presence of the product,
- first logic means for dividing the frame fill output that is proportional to the number of pixel locations that detect the presence of the product by the total number of pixel locations spanning the viewing frame,
- a photodetector for photodetecting light in a reflected color sorting band for each product passing through the viewing frame and producing a raw signal with an amplitude proportional to the total reflectivity in the color sorting band of the product and background in the viewing frame,
- second logic means for dividing the photodetected raw signal with the frame fill percentage output to produce a photodetected corrected signal so that the same lightness of photodetected product will produce the same amplitude of signal regardless of frame fill, and
- ejection means for producing an ejection signal for non-homogeneous products when the corrected signal exceeds a second predetermined trip level value.
9 more elements
Apparatus for producing uniform amplitude signals for products of the same detected color in a product stream that passes through a color sorting machine regardless of the amount of respective frame fill that is occupied by such products, comprising
- at least one optical viewing assembly including
- a light for producing at least one reflected color sorting band of light from the products in the product stream,
- a background which contrasts with the product stream,
- a viewing frame through which reflected light from the products in the product stream passes, and
- a plurality of detectors of the reflected color sorting band at respective pixel locations spanning said viewing frame on a line transverse to the axis of the reflected light through the viewing frame,
- each detector that detects background produces an output signal at a level below a predetermined trip line output value and
- each detector that detects the presence of a product in the product stream produces an output signal above the predetermined trip line level value, and
- output means for combining the output of the detectors to produce a frame fill percentage output for each detected product that is a percentage of the number of pixel locations that detect the presence of the product to the total number of pixels spanning the viewing frame,
- a photodetector for photodetecting for each product in a reflected color sorting band light passing through the viewing frame and producing a raw signal with an amplitude proportional to the total contrasting lightness of the product and background in the viewing frame, and
- logic means for dividing each of the photodetected raw signals with its respective frame fill percentage output to produce a respective photodetected corrected signal so that the same lightness of photodetected product will produce the same amplitude of signal regardless of frame fill.
7 more elements
Dependencies are inferred from the claim text.