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HemiView - Canopy Image Analysis System
Analyses Hemispherical Images
Calculates canopy structure parameters and solar radiation indices
Predicts radiation levels beneath canopy
The HemiView canopy image analysis system provides the hardware and software needed to acquire and analyse hemispherical images of forest canopies.
Designed for field use
Photographs are taken looking upwards from beneath the plant canopy, or from the forest floor, using a 180°fisheye lens and a high resolution digital camera. Uniform sky conditions are required, such as exist just before sunrise or sunset, or when the sky is evenly overcast. The digital camera is mounted in a Self-levelling Mount, type SLM9, to ensure it is held horizontally, whatever the mounting angle. The SLM9 also provides markers for the horizon and north-south axis, to assist with image alignment.
Powerful image analysis
The HemiView canopy image analysis system processes the image data file to obtain information about canopy structure e.g. Leaf Area Index (LAI), gap fraction and distribution of openings. By combining this information with radiation data, HemiView can predict the PAR intercepted and the radiation levels beneath the canopy. The software also calculates radiation indices, canopy indices, suntrack overlay and the direct and diffuse site factors; advanced graphing facilities help visualise the data. Data can be exported in several common formats.
The leaf area of a single tree can be calculated from HemiView outputs by using an Excel spreadsheet provided with the software.
The HemiView canopy image analysis system is frequently updated to take advantage of improvements in digital camera technology. The latest evolution, adding an even higher resolution digital SLR camera to the system, significantly improves HemiView's performance. Resolution can be the key to accurate analysis of hemispherical photographs, which is why we now supply an 18 megapixel SLR CMOS camera. The camera comes complete with a fibre optic flash transfer assembly (to illuminate the north/south image markers) and memory card.
A matching high quality fisheye lens and redesigned camera mount have also been introduced. The camera mount is considerably lighter than earlier versions, with improved the ergonomics. We have also introduced a new protective case that provides a safe and convenient way to store and transport the camera, lens and mount.
Please contact Delta T Devices for information on upgrading older HemiView models to the latest specification.
Leaf Area Index (LAI) in low canopies
HemiView is ideal for analysing and and characterising canopy cover in forests and woodland. However, for low regular canopies such as crops, the Delta-T SunScan System is the correct choice.