Advancements like nutrient monitoring and early disease detection are only possible using precise, repeatable measurements. To generate such measurements, a multispectral camera must be a “narrow band” camera.
Why Narrow Bands Matter
Contributed by | MicaSense
Reposted with permission from the MicaSense blog:
Multispectral imaging is changing traditional agricultural practices, allowing for more efficient resource management. However, not all multispectral cameras are alike. Advancements like nutrient monitoring and early disease detection are only possible using precise, repeatable measurements. To generate such measurements, a multispectral camera must be a “narrow band” camera. This article will explain why this is the case and delve deeper into the benefits of a narrow band multispectral sensor.
The goal of multispectral imagery
The primary goal of multispectral imaging in agriculture is to detect subtle variation in plant health before visible symptoms appear. For instance, a grower could spot a small reduction in a plant’s chlorophyll content before the leaves start to turn yellow.
Such early detection is possible because the amount of sunlight plants reflect in different wavelengths vary as their health changes. Multispectral sensors then capture and record this variation. However some sensors capture more precise data than others. If a sensor measures too broad a region of the light spectrum, any subtle variation will be lost.
The benefits of a narrow band sensor
To demonstrate, let’s examine the red edge waveband. The red edge band is located between the red and NIR bands and plays a key role in deriving plant chlorophyll content. If a plant is experiencing stress, it’s likely that variation will be the most obvious in the red edge band, as shown in the graph above. When comparing the red, red edge and NIR bands, the largest magnitude of change shows up in the red edge band, therefore it is the most critical to measure. A wide red edge waveband would likely overlap with neighboring bands and suffer from data contamination, resulting in a less precise measurement.
In agriculture, broadband sensors, such as converted cameras, work well for the big picture, allowing for the generation of RGB maps and generic indices like NDVI. However, the information provided by these cameras is limited and does not allow further analysis of the field over time.
A narrow band camera, on the other hand, provides more detailed and accurate information by capturing precise measurements of specific wavelengths, which allows for early detection of health issues. This gives farmers more tools and information to enable them to make better management decisions.
The content & opinions in this article are the author’s and do not necessarily represent the views of AgriTechTomorrow
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