Tau, a compact, lightweight thermal imaging core from FLIR Infrared Cameras & Thermal Imaging is helping UAVs inspect photovoltaic cells in solar plants for anomalies. 

Mounted underneath Unmanned Arial Vehicles (UAVs), also called drones, Tau is the perfect tool for the application in terms of imaging performance, size, weight and energy consumption, according to Antonio D’Argenio from Panoptes Srl.

Panoptes Srl, located in Palermo, Italy specialises in the development of scientific and technical instruments that can be used with lightweight drones.

Antonio D’Argenio, CEO of Panoptes explains the Panoptes project was initiated by their common interest in geo-information, UAVs and automation, beginning with small drones at the end of 2009 with the purpose of collecting aerial geo-data. 

Though they began with consumer cameras, they felt the need for cameras and thermal detectors especially designed for small drones. They designed Panoptes, a family of multi-sensor modules coupled with special software components to be used with small UAVs. 

mT-Panoptes: a specific multi-sensor platform for solar plant inspections

The first multi-sensor was the mini-Thermo (mT), a small and compact multi-sensor platform equipped with a thermal imaging camera and a CCTV camera. The mT-Panoptes is especially designed to be mounted underneath UAVs that are inspecting photovoltaic cells in solar plants.

Anomalies in photovoltaic cells and modules can cause a reduced efficiency of the entire system. Periodic preventive maintenance inspections are aimed at locating malfunctions. A fast and easy way to find anomalies in photovoltaic cells is using a thermal camera. A thermal imaging camera creates a crisp image based on subtle temperature differences and makes temperature differences visible. 

Often thermal inspections are carried out from the ground, or even using mobile platforms and helicopters. A new and innovative way to inspect photovoltaic cells in solar plants is the use of UAVs.

mT-Panoptes: an alternative for solar plant inspections

Used for photovoltaic cell inspections in solar plants, the mT-Panoptes records both thermal and visual high quality video on board during a flight using a two-channel mini DVR. The thermal imaging channel is transmitted in real time to the ground and the thermal data is presented in the dedicated Solar Inspector software.

The thermal camera is used to find anomalies. The visible camera can be used as a reference against the thermal image, helping to understand if the thermal anomalies are related to faults in modules or from external factors such as shadows.

The mTPanoptes multi-sensor is extremely lightweight and can be used on UAVs with low load capacity (<250 g). It integrates a FLIR Tau thermal imaging core that produces crisp thermal images of 640 x 512 pixels, as well as an HD (720p) video camera. The mT-Panoptes can easily be mounted on a small drone.

mT-Panoptes: combining unmanned flights with geospatial techniques

The Solar Inspector software offers a unique and intuitive environment for both operation in the field and for further analysis afterwards. The mT-Panoptes can be bundled with a tablet PC running Windows 8 Pro software, allowing for ease of use in the field. 

Collected thermal data is shown in real time with anomalies and their exact location in the solar plant indicated on a map of the plant. Solar Inspector also allows the videos recorded onboard to be replayed for reviewing the data anytime.

Antonio D’Argenio says the FLIR Tau has been chosen because it is the perfect core to be integrated into the mT-Panoptes. Apart from being compact and lightweight, the thermal imaging core also delivers excellent quality thermal images. Tau also has extremely low power consumption, which is important since the mT-Panoptes needs to operate on batteries.

Tau thermal imaging core: a perfect UAV component

The FLIR Tau thermal imaging core contains a maintenance-free, uncooled Vanadium Oxide (VOx) focal plane array (FPA) that produces crisp thermal images with a resolution of 640 x 512 pixels, which can be displayed on any monitor that accepts composite video.

The FLIR Tau thermal imaging core detects extremely small temperature differences of 50 mK. Its small size (44.5 x 44.5 x 30.0 mm), low weight (72 grams) and low power consumption (900 mW) make it the ideal core for mounting under a UAV for any application.

To further enhance the image quality of FLIR Tau, the thermal imaging core has a built-in advanced Digital Detail Enhancement (DDE) video processing algorithm, a sharpening filter that helps in making edges and other image details more distinct in both night and daytime conditions.

UAVs for solar plant inspections

A lightweight drone equipped with mT-Panoptes multi-sensor platform can perform fast inspections of solar plants. The Solar Inspector proprietary software, provided with mT-Panoptes can help to recognise anomalies and failures.

Solar Inspector also helps produce a comprehensive inspection report for the customer.