The science behind MicaSense series sensors


Share | 03/16/2017

At MicaSense, we believe in delivering more than pretty pictures. We believe in providing scientific solutions that address real problems. Whether it’s designing multispectral sensors that does not compromise or creating analytics that translate to dollars saved, focusing on solving real problems is how we bring value to our customers. Here is some of the science that powers our beliefs.

What multispectral sensing does

Multispectral sensing is the practice of using one sensor to image multiple areas of the light spectrum at the same time. When used in agriculture, multispectral sensing targets areas of the light spectrum that pertain to plant biology. Depending on factors such as growth stage, level of stress, or impact from disease, plants reflect light differently. Multispectral sensors measure this difference.

Plant reflectance graphic
One sensor can image specific sections of the visible and non-visible light spectrum, allowing for precise and accurate analysis.

The impact of drones

In the past, capturing multispectral data meant contracting a manned aircraft or waiting for a satellite to fly overhead. Both of these options do not allow for much flexibility, are limited in terms of resolution, and can be affected by cloud cover which can impact the data. Now, with the rapid expansion of the commercial drone industry, anyone can fly a multispectral sensor over a crop and very quickly pinpoint stress not just at the field level but at the individual plant level. This means that targeted scouting is available to more growers; fly a field, identify problem areas, then ground-truth quickly and effectively.

Why it matters

The ability to image crops frequently and at high resolution is changing the precision agriculture industry. Through analysis of drone-based multispectral data, farmers can take a seemingly lush, healthy field and pinpoint areas of stress, disease outbreak, or nutrient deficiency. Targeting such problem areas and treating accordingly means growers can increase efficiency, yield, and profit.

The vegetation index

Vegetation indices work by comparing the light a plant reflects in one band to the light reflected in another. For example, the commonly known index NDVI compares the reflectance of the Red band with that of the Near-Infrared band.

However, not every index is created equal. NDVI, for example, focuses on the “vigor” of a plant, or its “leafiness”. Oftentimes, it is wrongly assumed that vigor means a lack of disease. This is a crucial error and can represent the difference between effectively identifying and treating a disease or letting it spread. A similar comparison can be made in humans; a doctor wouldn’t look at a patient’s height or hair to tell if that patient was sick; instead she would use a thermometer to measure body temperature.

The full story: chlorophyll content

Research has shown that to truly assess plant health and not just vigor, chlorophyll content must be taken into account. To measure chlorophyll content, specific bands of light must be used. One such band, featured in the MicaSense series cameras, is the Red Edge band, an extremely narrow and precise band of light between Red and Near-Infrared. When used in conjunction with other bands and analyzed properly, bands like Red Edge provide a more accurate measure of plant health, having a bigger impact on a grower’s bottom line.

Moving forward

Turning multispectral imagery into crop health maps that a farmer can use is a highly complex process. At AgEagle, we have experts who focus on this process so that our customers don’t have to. Additionally, through Measure Ground Control, we can deliver advanced vegetation indices and analysis tools to our customers, helping them visualize their data and make changes to increase yield. This means that growers spend less time managing their data and more time making use of it.

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