Cell phone NDVI sensor

• US 8,902,413 B2
• Filed: 01/24/2013
• Issued: 12/02/2014
• Est. Priority Date: 02/21/2012
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Ulman, Morrison, Janky, James M
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): Lapage, Michael P
• Application Number:
  US13/749,587
• Publication Number:
  US 20130217439A1
• Time in Patent Office: 677 Days
• Field of Search: 356/445, 356/448, 356/416, 356/417, 356/419, 356/425, 356/51
• US Class Current: 356/73
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: H04M 1/0264 for a camera module assembly
• CPC Class Codes: H04M 2250/52 including functional features of a camera constructional features concerning the integration of cameras in portable phones H04M1/0264
• CPC Class Codes: H04N 23/00 Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

Apparatus and techniques for measuring and managing plant growth with cell phones or similar devices are described.

Claims

1. A method for measuring plant growth comprising:

capturing a first image of a plant at a first wavelength and a second image of the plant at a second wavelength with a camera in a cell phone;

processing the first and second images to compute a field vegetation index using a microprocessor in the cell phone;

determining the position and time that the images were acquired using a position sensor and clock in the cell phone; and

,

recording the field vegetation index, position and time in memory in the cell phone.

2. The method of claim 1 further comprising:

calibrating the spectrum of ambient light that illuminates the plant.

3. The method of claim 2 wherein calibrating is accomplished by use of a lookup table.

4. The method of claim 2 wherein calibrating is based on the position and time that the images were acquired.

5. The method of claim 4 wherein calibrating is further based on weather conditions at the position and time that the images were acquired.

6. The method of claim 2 wherein calibrating is accomplished by acquiring an image of a white reflector.

7. The method of claim 1 further comprising:

using the cell phone to communicate with a server via a wireless link to obtain an estimated reference vegetation index for the position and time at which the images were acquired.

8. The method of claim 7 further comprising:

using the cell phone to communicate with a server via a wireless link to obtain an estimated optimal fertilizer application rate based on the field vegetation index and the estimated reference vegetation index.

9. The method of claim 1 wherein the first and second images of the plant are obtained simultaneously.

10. The method of claim 1 wherein the first wavelength is about 660 nm and the second wavelength is about 780 nm.

11. The method of claim 1 wherein the vegetation index is a normalized difference vegetative index.

12. The method of claim 1 wherein the position sensor is a global navigational satellite system receiver.

13. The method of claim 12 wherein the global navigational satellite system receiver is a global positioning system receiver.