The crop water stress index (CWSI) was developed (in 1981) as a normalized index to quantify stress and overcome the effects of other environmental parameters affecting the relationship between stress and plant temperature. Workswell’s CWSI camera is the first device of its kind designed to map water stress across large areas in the field of precision agriculture. The aim of this method and device is to determine the value of water stress in the plant stand. For example, this information may be used to determine yield maps, optimize irrigation, or control water management remedies. Camera offers LWIR band sensor and 10x optical zoom RGB camera with resolution full HD (1920 x 1080 px).
Crop drought – actual and real valueIn the dry season what we are usually interested in is the actual effects of drought on crops. These impacts are not only dependent on the condition of the so-called climatic drought, but also on the groundwater drought, the size of the plant root system, etc. Measuring the water stress of plants with CWSI camera will help you to determine the actual and real effects of drought on the crop.
Potential yield maps
Based on the value of water stress, an approximate potential yield map can be determined. Obviously, the more plants are hit by drought, the lower their yield. Worksell CWSI Analyzer software, that comes in bundle with CWSI camera, makes it possible to generate potential yield maps from a large number of images across many hectares in a very short time (Challenging calculations common, for example, for orthophotogramers are not needed).
With CWSI camera you can get actual values of crop water stress during the flight, or you can use the collected data to create an overview map. By comparing yields from different years depending on water stress, a potential yield map can be created according to the current water stress value.
Objectification of corrective actionsBased on CWSI camera data, it is possible to effectively plan remedial measures and, in particular, to evaluate measures related to water and drought management of plants. With CWSI camera it is then possible to see the impact of water management directly on the most important thing, ie the growth.
Use case: Irrigation Optimization – optimizing sensor locations
The potato field is under controlled irrigation. Irrigation optimization is based on data from soil sensors. However, as the CWSI camera image shows on the right, irrigation control is not optimal – some sites are converted (wasting water) and others are irrigated insufficiently. The solution is to better position the soil sensors, which is also aided by the captured image.
Why is the CWSI for water management more valuable than NDVI
CWSI and NDVI are two very different indexes that only share the fact that they provide information about the state of crop. While NDVI, until now probably the most widely used index, is de facto based only on crop color in various parts of the spectrum (including near infrared), CWSI provides additional information on how the crop is really hit by drought. So CWSI is about how the crop is actually actually suffers or does not suffer by a lack of water. Therefor Workswell patented CWSI camera technology brings more valuable information about the crop stress and water management than NDVI.
Software CWSI Analyzer
Workswell CWSI Analyzer is a desktop software used to processing of CWSI images. It allows setting of individual parameters necessary for correct calculation of CWSI, both tabular and additional measurement. The software includes predefined most common crops where table values are entered directly. The big advantage of the software is the ability to process hundreds of images at once (mass data processing).
The software is supplied free of charge to the CWSI camera.
Main benefits of CWSI camera
Although there are many uses, we can divide the main CWSI camera usage into these three applications:
✅ Water status monitoring – To monitor water stress, ie. the lack of water that the crop is exposed to during the growing season. And regardless of whether the crops are irrigated or not. Special colour map “Crop” and “CropStep” are avaible.
✅ Manage irrigation management – Irrigation system optimization both in terms of determining suitable locations for the location of soil sensors and in terms of structure optimization. Special colour map “Water” and “WaterStep” for that application are avaible.
✅ Phenotyping – Different plant varieties are susceptible to the amount of water available. The CWSI camera will help you determine how often the plants of a given species are in water stress, compared to plants of other species.
Many interfacesWorkswell CWSI camera Pro also brings an interface enabling the widest range of connections to the drone, the control unit, an external GPS sensor etc. Wi-Fi low latency live video streaming and command link is also available. The following HW interfaces are avaible:
- CAN bus (DJI M600 and A3 controller compatible)
- Ethernet (RJ 45)
- external GPS connection
- external trigger
128 GB SSD disk, external USB disk or microSD cardWorkswell CWSI camera is equipped with an internal SSD disc with 128 GB memory for recording. It is also possible to save data to external USB disk or microSD card.
Weight and Dimensions
Workswell’s CWSI camera weighs less than 430 g, which is very convenient for drone usage.
WEIGHT: < 430 g
DIMENSIONS : 83 x 85 x 68 mm
|CWSI Camera key features description|
|CWSI onboard processing||Evaluation of Crop Water Stress Index onboard|
|Operating onboard system||CWSI OS for full real-time data streaming and evalution during the flight
– operating system ensures the full access to all camera functions
– easy camera control via S.Bus, CAN bus, MavLink, RJ-45 or Trigger
|10x Optical Antivibration zoom||Full HD 10x optical zoom camera with anti-vibration compensation|
|CWSI camera specification|
|CWSI sensor resolution||640 x 512 pixels|
|CWSI evaluation||Workswell patented CWSI camera technology based on crop water stress index (normalized to value from 0 to 1) brings information about the crop stress and crop water management on large areas. The information can then be used to determine yield maps, manage irrigation or implement water management related remedies.|
|FPA active sensor size||1.088 x 0.8705 cm|
|Type of sensor||LWIR band sensor|
|CWSI evaluation range||0 – 1 (1 means very stressed)|
|Temperature sensitivity||0.03 °C (30 mK)|
|CWSI calibration||Yes, calibrated for different ambient temperatures|
|Field of view of the lens||45°|
|CWSI Colour-map||4 colour maps for CWSI and Water management evaluation|
|CWSI range settings||Automatic, manual or span|
|CWSI digital zoom||1 – 14x continuous|
|Software CWSI analyzer||Yes, included in the package|
|Digital visual camera|
|Resolution||1 920 x 1 080 pixels (Full HD),
Auto white balance,
Wide dynamic range,
Exposure and Gamma control
|Optical zoom||10x optical zoom with vibration compensation|
|View angle||Ultra zoom 6.9° – extra wide 58.2°, focal 33.0 mm – 3.3 mm|
|Noise reduction||Special 3D noise reduction function|
|Focus||Autofocus with Direct Focus Zoom synchronization|
|Memory and data recording|
|Memory||Internal high-speed SSD 128 GB for image and video recording
External slot for Micro SD card & USB 2.0 for USB stick for taking images
|Image and video formats||CWSI JPEG images and Digital camera Full HD JPEG images
Digital camera h.264 encode video HD recording
Full-frame CWSI video recording (raw data recording)
|GPS geo-tagging (image & video)|
|GPS tagging (image & video)||MavLink or External GPS or DJI A3 controllers compatible via CAN bus|
|Interfaces & real-time remote control|
|10-pin digital port||S.Bus
CAN bus (compatible with DJI M600 and A3 controllers)
External GPS connectivity
|Ethernet (RJ-45) port||Video streaming and camera control (optional on request only)|
|Micro USB 2.0 port||Mass storage
Camera control and video streaming (optional on request only)
|USB 2.0 port||Keyboard connection for in-house WIRIS camera control|
|Remote control system||CWSI OS ensures real-time control of all camera functions during the flight|
|Remote control options||S.BUS protocol
CAN bus for real-time control on DJI M600 and GPS geo-tagging
RJ-45 for wireless uplink installation (video streaming and camera control)
|Protective filter on lens||Filter protects the lens against external damage during the flight|
|Camera functions||Measurement functions:
– online CWSI evaluation
– spot CWSI evaluation (Centre)
– area CWSI evaluation (Max and Min)
– capturing CWSI image and Visible image simultaneously
|Camera modes visualization||Full-screen mode, Picture-in-Picture, Full Dual-screen, Dual-screen|
|Micro HDMI video output||1 280 x 720 pixels (720p), Aspect ratio 16:9, Micro HDMI video output|
|Software & SDK|
|Desktop software||Advanced Workswell CWSI analyzer for CWSI evaluation|
|Power supply, weight & dimensions|
|Input supply voltage||9 – 36 VDC, Coaxial 2 x 6.4 mm, outer shell – GND|
|Power dissipation (avg.)||12 W|
|Weight||< 430 grams|
|Dimensions (L x W x H)||83 mm x 85 mm x 68 mm|
|Mounting||2 x 1/4-20 UNC thread (1x bottom side, 1x upper side)|
|Housing material||Durable aluminium body for long-time measurement stability|
|Operating temperature range||-10 °C to +50 °C|
|Storage temperature range||-30 °C to +60 °C|
CWSI camera documents