Naiqian Zhang

Development and evaluation of thermal infrared imaging system for high spatial and temporal resolution crop water stress monitoring of corn within a greenhouse

The greenhouse thermal imaging system had a ?0.62?C (α=0.05) measurement accuracy.Unstressed canopy temperatures followed closely to characteristic crop water use.Canopy temperature is a viable water stress indicator throughout growth stages.Spatial and temporal canopy temperature provide accurate crop health assessment.82% of soil moisture variation was explained by CWSI values above 0.6. Inadequate water application often decreases yield and grain quality. Existing methods using single, localized soil moisture or canopy temperature measurements do not account for crop water stress on both a high spatial and temporal resolution for precision irrigation water management decisions and scheduling. Therefore, this study was conducted to understand the feasibility of thermal cameras in order to quantify high resolution spatial canopy temperatures in relation to soil moisture. The objectives of this study were to deploy a thermal infrared imaging system (TIRIS) for high spatial and temporal monitoring of corn canopy temperature in greenhouse, test camera durability and measurement accuracy during full-season crop development, remove background temperatures with image segmentation, and sample individual plants to investigate full-season crop water stress versus soil moisture content. A TIRIS was developed using a lightweight uncooled thermal camera. Corn plants were divided into well-watered and water-stressed irrigation zones to observe stress from water deficits. Canopy temperatures were used to develop empirical canopy and air temperature deficit versus vapor pressure deficit linear regressions. Results showed that the TIRIS system maintained measurement accuracy of ?0.62?C (α=0.05) while compensating for changing ambient greenhouse conditions. Canopy and air temperature deficit versus vapor pressure deficit regression equations revealed that the predicted canopy temperature was closely related to characteristic water use. Results of the 80-day study demonstrated that 82% of soil moisture variation was explained by the crop water stress index (CWSI) values between 0.6 and 1.0. Results indicated that the CWSI derived by remotely measuring canopy temperature using TIRIS can be used as an alternate irrigation scheduling method in order to quantify spatial and temporal soil moisture variability.

Monitoring Sediment Concentration at a Low-water Stream Crossing Using an Optical Sediment Sensor

An optical sediment sensor was designed to measure pure sediment concentration in water. The sensor uses light sources of different wavelengths in the visible and infrared wavebands and light detectors arranged at different angles from the light sources to reduce the influence of water type and soil texture on sediment measurement accuracy. An algorithm was developed to reduce the influence of ambient light on the measurement. The design was simplified based on a statistical analysis of laboratory test data. Three prototype sensors with waterproof packaging were fabricated based on the simplified design and were placed at a low-water crossing at Fort Riley for long-time monitoring. Preliminary field data were obtained after rainstorm events.

Infusing system design and sensors in education

INSIGHT, an innovate graduate STEM Fellowship Program integrates sensor technology and computer science within in a K-12 standards-based science, technology, and engineering curricula. Graduate STEM Fellows are teamed with science, technology, and physical education teachers for two years to carry out hands-on classroom activities utilizing technology and engineering practice with a focus on the use of sensors, computing, and information technology aligned with K-12 state curriculum standards. One of the projects main goals is the establishment of sensor, computing, and information technology as a foundational high school skill by accelerating the integration of sensor technology content into K-12 classrooms. This project encourages participation in engineering and technology from a wider, more diverse group of students from rural Kansas. This paper shares detailed examples of summer institute and academic-year K-12 activities that have been successful. It also provides a preliminary assessment of the project.

An Optical Sediment Sensor Integrated with Flow Velocity Measurement

Flow velocity measurement is usually conducted with SSC measurement to assess sediment mass transport at a given time and depth. However, flow velocity and sediment concentration measurements that were conducted by different sensors could result in time mismatch, and high cost for equipment. An optical sediment sensor integrated with flow velocity measurement based on cross-correlation principle was tested in this study. Flow experiments were conducted in the laboratory to examine the sensor performance on velocity measurement using a closed circulation system. A solution of blue colorant, Brilliant Blue FCF, was used as an artificial absorbent to create signal variation pattern when water flow that carries the colorant passed through the sensor. Flow velocity was calculated based on the patterns using the cross-correlation principle. The results indicated that the cross-correlation-based velocity sensor was capable of measuring water flow velocity using the dye injection method.

Long-term Field Test of an Optical Sediment-Concentration Sensor at Low-Water Stream Crossings

Suspended sediment concentration (SSC) is one of the most important indicators of water quality. Monitoring SSC in field settings is also fundamental to determine the sediment transportation. An optical sediment-concentration sensor was developed to allow real-time monitoring of sediment concentration at low-water stream crossings. Long-term field tests were conducted at two low-water crossings in Kansas and Georgia to evaluate the sensor performance, and the effect of fouling, including bio-fouling, on the measurement. Methods of removing the fouling effect through data correction were also developed.

Methods for measuring suspended-sediment concentration in streams

Turbidity sensors are frequently used for real-time measurement of solids concentration in water. Non-soil objects present in a water sample, including algae, organic matter, various microorganisms, colloidal material, and dissolved molecules such as tannins and lignins, may affect the turbidity readings. This paper reviews various technologies for sediment concentration measurement, presents the experimental results of a simple and inexpensive turbidity sensor developed in this study for measuring sediment concentration, and discusses potential approaches to improve the sensor.

IEEE 1451 standards: can the “smart transducer concept be used in system integration for precision agriculture?

As an increasing number of electronic control units with various types of sensors and actuators are embedded in agricultural machines, systematic and efficient system integration has become a critical issue. A recently developed agricultural bus standard, ISO 11783, provides a platform for mobile equipment communications, enabling a plug-and-play capability for implement controllers made by different manufacturers. This paper further recommends the use of the IEEE 1451 standards to design “smart transducers” to facilitate system integration. In this paper, the IEEE 1451 standards are reviewed, the relationship between ISO 11783 and IEEE 1451 is analyzed, an example of a smart weed sensor conforming to IEEE 1451 standards is designed, and the advantages and disadvantages of this implementation are discussed.