a low-cost dual-camera imaging system for aerial applicators
TRANSCRIPT
A Low-Cost Dual-Camera Imaging
System for Aerial Applicators
Chenghai Yang, Clint Hoffmann
Fred Gomez, Lee Denham,
Dan Martin, Brad Fritz, Phil Jank
USDA-ARS
Aerial Application Technology
Research Unit
College Station, TX
49th NAAA Convention & Exposition, Savannah, GA, Dec. 7-10, 2015
A Single-Camera Imaging System
Monitor
GPS
Trigger
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Why Do You Need a Dual-Camera
Imaging System?
• A single camera only allows you to capture RGB color images.
• A dual-camera system has the capability to capture both RGB and near-infrared (NIR) images.
• With RGB and NIR, you can create vegetation indices (i.e., NDVI) for crop assessment and variable rate application.
• Some aerial applicators expressed interest in such a system.
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Official Publication of the National
Agricultural Aviation Association
Sept./Oct. 2015, Vol. 42, No. 5, p. 44-47
Nikon D90 camera
with Nikon 24mm lens $1000
Modified Nikon D90
camera with 720-nm filter $1300
Nikon GP-1A GPS unit $200
Giga T Pro II Wireless
timer remote control $100
Optional LCD monitor $100
Imaging System Components
Total: $2700
Dual-Camera Imaging System
Camera is attached to left step on AT-402B
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Airborne Image Acquisition
• Weather: Clear and calm days
• Time: 10:30 am to 3:30 pm
• Altitude: 500-10,000 ft
• Speed: 100-150 MPH
• Keep your aircraft straight and level!
RGB and NIR Images - 5000 ft AGL
Coverage: 5000 ft x 3300 ft (380 ac)
Pixel array: 4288 x 2888
Pixel size: 14 in. or 35 cm
RGB=R+G+B NIR
Create Color-infrared (CIR) Image & Normalized
Difference Vegetation Index (NDVI) Using QGIS
1. QGIS - free GIS/image
processing software
2. Align RGB and NIR images
3. Geo-reference images
4. Create vegetation indices
such as band ratios and
NDVI
5. Classify RGB/NIR and NDVI
images into management
zones for variable rate
application
Color-Infrared (CIR) Image
RGB=R+G+B CIR=NIR+R+G
Normalized Difference Vegetation Index
(NDVI) Image
CIR=NIR+R+G
NDVI=(NIR-R)/(NIR+R)
Take Continuous Images from a Large Area
along Flight Lines
5000 ft AGL
60% overlap
2000 ft interval
11 flight lines
150 MPH
6 s per image
418 RGB images
418 NIR images
4 mi x 8 mi
20480 ac
Create Mosaicked Image Using Adobe
Photoshop CC or Pix4D
RGB CIR
Managing Winter Weed Using Aerial
Imagery and Variable Rate Technology
• Map henbit infestation and create prescription
maps from airborne imagery
• Perform site-specific (on/off) herbicide application
• Assess performance of site-specific herbicide
application
Henbit
Create Prescription Map
• Acquire RGB & NIR images
• Align and georeference RGB and NIR images
• Generate NDVI image
• Create prescription map from NDVI image
Prescription
map RGB CIR
Site-Specific Aerial Glyphosate Application
with AT-402B equipped with IntelliStar System
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Pilot: Mr. Kenneth Lauderdale
Date: March 13, 2015
As-Applied Herbicide Map
Prescription Map As-Applied Map
Remote Sensing Assessment of Site-
Specific Herbicide Treatment on Henbit
Image: 3-06-15
Spray: 3-13-15 Image: 3-27-15
