Benefits of a Professional Multispectral Sensor


RGB

RGB

NDVI

NDVI

Chlorophyll Map

Chlorophyll Map

How does a multispectral sensor work?

A multispectral sensor measures the reflectance of a plant at different wavelengths, identifying the areas of stress in a plant, which then provides a quantitative measure for overall pant health.

Features of Multispectral Sensors

Not all multispectral sensors are created equal; with nuances between the target spectral range, shutter type, calibration functionality and whether it’s a professional multispectral sensor versus a converted single-imager camera (among other things). It’s a complex space to navigate and it’s important that you’re capturing valuable, accurate data with your sensor and ensuring that critical insight is delivered in the output -- because that’s what’s driving your decisions. The most important things to know when purchasing a sensor are:

  • There's more than NDVI (and it's not all created equal)
  • Calibrated data is important for comparison over time (think long-term detection)
  • Location of the narrowband imagers (this affects the contrast in imagery and detail in the analytical output)

Multispectral Sensors


At-a-Glance Comparison

 

MicaSense RedEdge

Parrot Sequoia

 

Performance


Number of Bands

(Narrowbands)

The more bands a multispectral sensor has, the more analysis can be done to the output.

5 Bands

(Red, Green, Blue, Red Edge, Near- infrared)

Global Shutter

Sharp RGB true color images simultaneously captured on same flight as precise multispectral data

4 Bands

(Red, Green, Red Edge, Near-infrared)                                                                                                           

Global Shutter

 

Blue Band


Resolution

Measured as Ground Sample Distance (GSD) for individual images and mosaic outputs

3.1 in p/pixel at 400 ft GSD

AGL = 8.1 cm p/pixel

 

*CIR comparison image

5.1 in p/pixel at 400 ft GSD

AGL = 13 cm p/pixel

 


RGB Color Image

For true color scouting and analysis

Yes

Global Shutter = no distortion/blurring

Yes

Rolling Shutter


Light Sensor

Corrects reflectance for cloudy conditions

Yes

Enables gimbaled installation of camera sensor

Yes


RTK Capability

For precise position accuracy using advanced GPS systems

Yes

Sync output pulse for synchronization of images

No

*RTK available with senseFly eBee

Calibration

For accurate and repeatable data across time

Yes

Yes

Bit Depth (Narrowband)

For higher contrast data and detection of more subtle changes in a crop

12 Bit

(4,096 values)

 

10 Bit 

(1,024 values)

 

Integration

Weight

5.8 ounces / 165 grams

3.9 ounces / 110 grams

Power Usage

Lower power has less effect on endurance and flexible integrations for heat dissipation

4 Watts

10 Watts

IMU

Inertial Measurement Unit for measuring pitch/roll/yaw angles

Yes

Yes

Interface Options

External Trigger

For easy integration with multiple common autopilots

Yes

Servo pulsewidth or low/high logic signal

No

Serial    

MAVLINK communication for tight integration with aircrafts

Yes

No

Ethernet

For high speed interconnect with aircraft systems and advanced integration capabilities

Yes

Enables real-time data transfer to host aircraft, live thumbnail support

No

USB

No

Yes

Custom Bands

For research applications that go beyond stock bands

No