Apparatus and method for determining a distance to an object in a field for the controlled release of chemicals on plants, weeds, trees or soil and/or guidance of farm vehicles
DCFirst Claim
1. A method, comprising:
- moving a source of light and a light detector with respect to objects in a field, said source of light emitting modulated light which reflects off said objects;
filtering a signal output from said light detector thereby discriminating components of said signal due to said modulated light which reflects off said objects from components of said signal due to ambient light; and
generating information indicative of distances to said objects and information indicative of whether said objects are living plants.
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Abstract
An optical proximity sensor generates information indicative of a distance to an object in a field and in some embodiments also generates information indicative of a spectral reflectance characteristic of the object. The information indicative of the spectral reflectance characteristic can be used to determine whether the object in the field is a living plant or another object such as soil. Light emitted from the optical sensor for reflection off the object is modulated so that reflected light from the optical sensor can be discriminated from reflected ambient sunlight. The optical sensor is scanned over the field to map objects in the field and/or to determine the location of rows of crop plants. A sensor in accordance with the present invention has many uses in agriculture including spraying, cultivation and vehicle guidance.
222 Citations
53 Claims
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1. A method, comprising:
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moving a source of light and a light detector with respect to objects in a field, said source of light emitting modulated light which reflects off said objects; filtering a signal output from said light detector thereby discriminating components of said signal due to said modulated light which reflects off said objects from components of said signal due to ambient light; and generating information indicative of distances to said objects and information indicative of whether said objects are living plants. - View Dependent Claims (2)
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3. A method, comprising:
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moving a sensor with respect to an object in a field, said sensor comprising a source of light and a light detector, light from said source of light scanning over said object and light from said source of light reflecting off said object and being incident upon said light detector of said sensor, said light reflecting off said object causing a signal to be output from said light detector of said sensor; using a signal output from said light detector of said sensor to obtain distance information, said distance information being indicative of a distance between said sensor and said object when said light from said source is reflecting off said object; and using a signal output from a light detector of said sensor to determine a spectral reflectance characteristic of said object, said spectral reflectance characteristic being indicative of whether said object is a living plant. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Structure for outputting information indicative of a distance to an object in a field, comprising:
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a source of light of a first wavelength and light of a second wavelength, said light of said first wavelength being modulated by a first modulation signal, said light of said second wavelength being modulated by a second modulation signal; and a light detector having a first portion and a second portion, light from said source which has reflected off said object being incident on said first portion but not on said second portion if said object is located a first distance from said light detector, light from said source which has reflected off said object being incident on said second portion but not on said first portion if said object is located a second distance from said light detector. - View Dependent Claims (16, 17, 18, 19, 20)
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21. Structure comprising:
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means for obtaining information indicative of a distance to an object in a field; and means for determining whether said object is a plant.
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22. A method, comprising:
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electronically detecting light which has reflected off an object in a field; making a determination whether said object has a spectral characteristic of a plant; and guiding a vehicle or an implement through said field with respect to said object based at least in part on said determination. - View Dependent Claims (23, 24)
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25. A method, comprising:
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electronically detecting light which has reflected off an object in a field; obtaining information indicative of a distance to said object; and guiding a vehicle or an implement through said field with respect to said object based on said information. - View Dependent Claims (26, 27)
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28. A method, comprising:
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moving a first sensor with respect to a tree, said first sensor comprising a source of light and a light detector, said first sensor outputting information indicative of a distance to said tree; moving a second sensor with respect to said tree, said second sensor comprising a source of light and a light detector, said second sensor being coupled to an electronically-controlled spray nozzle; and selectively disabling said electronically-controlled spray nozzle based at least in part on said distance information output from said first sensor, said second sensor otherwise controlling said electronically-controlled spray nozzle to spray objects having a predetermined spectral characteristic. - View Dependent Claims (29)
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30. A method, comprising:
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moving a light detector over a surface of a field to obtain spectral reflectance information; forming a two-dimensional map of at least a part of said field using said spectral reflectance information by classifying areas of said surface of said field based on their spectral reflectance characteristics, some of said areas being plants disposed in a row and others of said areas being soil; and analyzing said two-dimensional map to locate said row of plants, said forming and analyzing occurring in a digital processor moving over said surface with said light detector. - View Dependent Claims (31, 32, 33, 34)
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35. A method, comprising:
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moving a light detector over a surface of a field to obtain distance information; forming a two-dimensional map of at least a part of said field using said distance information to classify said areas of said surface, some of said areas being plants disposed in a row and others of said areas being soil; and analyzing said two-dimensional map to locate said row of plants, said forming and analyzing occurring in a digital processor moving over said surface with said light detector. - View Dependent Claims (36)
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37. A method comprising:
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electronically detecting light reflecting off a plant in a field and obtaining therefrom spectral information; and determining whether said spectral information is indicative of a spectral characteristic of a first type of plant or is indicative of a spectral characteristic of a second type of plant. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44)
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45. A method, comprising:
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transmitting, from a location on one side of a row of crop plants in a field, substantially monochromatic light of the first wavelength and substantially monochromatic light of a second wavelength toward an object disposed in said row; and receiving, at a location on the opposite side of said row of crop plants, a portion of said substantially monochromatic light of said first and second wavelengths which has reflected off said object. - View Dependent Claims (46, 47, 48, 49, 50, 51)
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52. A structure, comprising:
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a source of light; a light detector;
means, coupled to said light detector, for determining whether an optical path between said source of light and said light detector is obstructed, light traveling in said optical path from said source of light to said light detector having to reflect off an object in order to reach said light detector; andan electronically-controlled plante-eliminating device coupled to said means for determining. - View Dependent Claims (53)
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Specification