Developing a Thermal Imaging System for On-demand Corn Temperature Profiles for Variable Rate Irrigation

Project Overview

Project Type: Graduate Student
Funds awarded in 2014: $10,000.00
Projected End Date: 12/31/2014
Grant Recipient: Kansas State University
Region: North Central
State: Kansas
Graduate Student:
Faculty Advisor:
Dr. Ajay Sharda
Kansas State University


  • Agronomic: corn


  • Crop Production: irrigation
  • Farm Business Management: feasibility study, whole farm planning
  • Production Systems: general crop production
  • Sustainable Communities: employment opportunities, sustainability measures


    Precise water application conserves resources, reduces costs, and optimizes plant performance and quality. Existing irrigation scheduling utilizes single, localized measurements that do not account for spatial crop water need; but, quick, single-point sensors are impractical for measuring discrete variations across large coverage areas. Thermography is an alternate approach for measuring spatial temperatures to quantify crop health. However, agricultural studies using thermography are limited due to previous camera expense, unfamiliar use and calibration, software for image acquisition and high-throughput processing specifically designed for thermal imagery mapping and monitoring spatial crop water need. Recent advancements in thermal detectors and sensing platforms have allowed uncooled thermal infrared (TIR) cameras to become suited for crop sensing.

    Therefore, a small, lightweight thermal infrared imaging system (TIRIS) was developed capable of radiometric temperature measurements. A one-time (OT) radiometric calibration method was developed and validated for repeatable, temperature measurements while compensating for strict environmental conditions within the field. A TIRIS was built for high-throughput image capture, correction, and processing and RT environmental compensation for temperature mapping aboard a small unmanned aerial systems (sUAS). Similarly, static validation aboard static and dynamic platforms provided radiometric thermal images with a ±0.60°C (α=0.05) measurement accuracy. Due to the TIR cameras’ performance, a TIRIS could provide unparalleled spatial coverage and measurement accuracy capable of monitoring subtle crop stress indicators on sensing platforms intended for extended coverage area. Further studies need to be conducted on dynamic sensing platforms to produce spatial crop water stress maps at scales necessary for variable rate irrigation systems.

    Project objectives:

    By simplifying image acquisition and application solutions, producers, agricultural service providers, and researchers will have acquisition system for capturing high spatial surface temperatures to develop management solutions to better allocate available water resources for variable rate irrigation. Therefore, research objectives were to develop (1) an environmentally compensated thermal infrared imaging system (TIRIS) capable of measuring accurate surface temperatures at accuracies and resolutions sensitive to crop health monitoring, (2) a small, lightweight TIRIS package for temperature mapping aboard a multirotor sUAS, (3) a complementary hardware and software package to radiometrically calibrate the TIRIS during infield setup while providing in-flight ground truthing.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.