Method and apparatus for sorting a flow of objects as a function of optical properties of the objects
First Claim
1. A method for sorting objects as a function of optical properties of the objects, comprising:
- conveying the objects over an object plane, all the objects passing a strip of the object plane;
detecting light rays originating from the strip by one or more image pick-up units which each have a row of image pick-up elements in an image plane of the image pick-up unit;
and for each image pick-up unit;
repeated scanning of the row of image pick-up elements to form a primary line signal which contains image information which is a function of the optical properties of the objects and which comprises, for each scan, a primary group of primary intervals corresponding to the image pick-up elements;
comparing the line signal with at least one reference signal; and
energizing, as a function of the result of comparison, an ejection device, corresponding to the comparison time instant, of a number of ejection devices for the objects arranged downstream of the strip and corresponding to sections of the strip;
and comprising consecutively assigning, in accordance with a predetermined scheme, the image information, obtained during a scan, of each group of primary intervals to a corresponding secondary group of equal secondary intervals of a secondary line signal in a manner such that the distribution of the information assigned to a secondary group corresponds linearly to the distribution of the optical properties in the strip, each secondary interval corresponding to an associated sub-section of the strip, each having an equal length.
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Accused Products
Abstract
Method and apparatus for sorting objects dependent on optical characteristics thereof. The objects are conveyed through a longitudinal sorting zone. Light reflected from the objects passing the zone is detected by at least one imaging device having at least one single line array of equally spaced light sensitive imaging elements. The line array of imaging elements is repeatedly read out in series for providing a primary line signal comprising for each scan of the line array a primary group of primary intervals corresponding to respective imaging elements. Information representing light detected by each group of primary intervals is allocated to a secondary group of secondary intervals having the same duration of a secondary line signal for each scan such that the distribution of information allocated to a secondary group corresponds linearly to the distribution of the optical properties in the zone. Allocation is possible by scanning each imaging element for the same period of time and storing the information thus obtained in one or more locations of a memory according to a predetermined distribution table. Allocation is also possible by scanning the imaging elements with different periods of time dependent on a predetermined duration table providing the secondary line signal which can be supplied to a memory which receives a constant clock frequency during writing thereof. In each case the second line signal is provided when the respective memory is read out with a constant clock frequency. Secondary intervals of secondary line signals obtained from different imaging devices may then relate to identical parts of the zone for comparison purposes and for driving object rejectors corresponding to the parts dependent on the comparison results.
75 Citations
14 Claims
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1. A method for sorting objects as a function of optical properties of the objects, comprising:
- conveying the objects over an object plane, all the objects passing a strip of the object plane;
detecting light rays originating from the strip by one or more image pick-up units which each have a row of image pick-up elements in an image plane of the image pick-up unit;and for each image pick-up unit;
repeated scanning of the row of image pick-up elements to form a primary line signal which contains image information which is a function of the optical properties of the objects and which comprises, for each scan, a primary group of primary intervals corresponding to the image pick-up elements;comparing the line signal with at least one reference signal; and
energizing, as a function of the result of comparison, an ejection device, corresponding to the comparison time instant, of a number of ejection devices for the objects arranged downstream of the strip and corresponding to sections of the strip;and comprising consecutively assigning, in accordance with a predetermined scheme, the image information, obtained during a scan, of each group of primary intervals to a corresponding secondary group of equal secondary intervals of a secondary line signal in a manner such that the distribution of the information assigned to a secondary group corresponds linearly to the distribution of the optical properties in the strip, each secondary interval corresponding to an associated sub-section of the strip, each having an equal length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- conveying the objects over an object plane, all the objects passing a strip of the object plane;
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9. An apparatus for sorting a flow of objects as a function of optical properties of the objects, comprising:
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conveyance means for conveying the objects over an object plane, all the objects passing a strip of the object plane; light pick-up means which comprise one or more image pick-up units each having a row of image pick-up elements in an image plane of the image pick-up unit, each image pick-up unit scanning the optical properties of the strip along a line and delivering a corresponding primary line signal which comprises, for each scan, a primary group of primary intervals corresponding to the image pick-up elements; ejection means for the objects arranged downstream of the strip; and for each image pick-up unit; comparison means for comparing the image signal with at least one reference signal; and in which the ejection means are linked to control means which energize an ejection device corresponding to the comparison time instant as a function of the comparison result, and comprising a first memory in which a scheme for assigning, during each scan, secondary intervals of a secondary group of a secondary line signal to the primary intervals is stored, the number of secondary intervals of a secondary group being greater than the number of primary intervals of a primary group; first addressing means which receive a primary clock signal with a clock pulse for each primary interval and which address the first memory; a clock pulse increasing circuit which receives an output signal from the first memory and which delivers an assignment clock signal with a pulse for each primary interval plus a number of additional pulses which is a function of the output signal of the first memory; a second memory which is written into during a first period and during this process receives the primary line signal and which is read out during a second period and during this process delivers the secondary line signal; and
second addressing means which, during the first period, address the second memory as a function of the assignment clock signal and which, during the second period, address the second memory as a function of a secondary clock signal. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification