HANDHELD OPTICAL SENSOR FOR MEASURING THE NORMALIZED DIFFERENCE VEGETATIVE INDEX IN PLANTS
First Claim
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1. A handheld sensor comprising:
- a microcontroller;
a current pulse control unit coupled to a light emitting diode (LED); and
a photodiode;
wherein the microcontroller controls the current pulse control unit to provide a pulsed illumination of a target plant and the photodiode reads a magnitude of light energy reflected from the target plant; and
wherein the microcontroller accepts the reading from the photodiode and computes a normalized difference vegetative index (NDVI) based at least on the reading.
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Abstract
A handheld sensor is disclosed. The sensor has a microcontroller, a current pulse control unit coupled to a light emitting diode (LED), and a photodiode. The microcontroller controls the current pulse control unit to provide a pulsed illumination of a target plant and the photodiode reads the magnitude of the reflectance from the target plant. The microcontroller accepts the reading from the photodiode and computes a normalized difference vegetative index (NDVI) based at least on the reading.
47 Citations
17 Claims
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1. A handheld sensor comprising:
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a microcontroller; a current pulse control unit coupled to a light emitting diode (LED); and a photodiode; wherein the microcontroller controls the current pulse control unit to provide a pulsed illumination of a target plant and the photodiode reads a magnitude of light energy reflected from the target plant; and wherein the microcontroller accepts the reading from the photodiode and computes a normalized difference vegetative index (NDVI) based at least on the reading. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of determining a normalized difference vegetative index (NDVI), comprising:
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illuminating a plant with a pulsed light source of at least two wavelengths; detecting a magnitude of the pulsed light source on each of the at least two wavelengths; detecting a magnitude of light reflected from the plant on each of the at least two wavelengths; and computing the NDVI with a microcontroller based on the detected magnitudes of light. - View Dependent Claims (9, 10, 11)
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12. An optical sensor for determining a normalized difference vegetative index (NDVI) of a plant, comprising:
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an near infrared light emitting diode; a visible light emitting diode; an incident light detecting photodiode that detects incident light from the near infrared and visible light emitting diodes and generates a first electrical signal in response; a reflected light photodiode that detects light reflected from the near infrared and visible light emitting diodes by a plant canopy and generates a second electrical signal in response; a first pulse passing filter that filters the first electrical signal from the incident light photodiode to reject at least a part of unwanted signals resulting from sources other than the near infrared and visible light emitting diodes; a second pulse passing filter that filters the second electrical signal from the reflected light photodiode to reject at least a part of unwanted signals resulting from sources other than the near infrared and visible light emitting diodes; and a microprocessor that determines the NDVI based at least on the first filtered electrical signal and the second filtered electrical signal. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification