Applications of Smartphone-Based Sensors in Agriculture: A Systematic Review of Research

Table 2

Summary of smartphone-based sensors in agricultural context.

Sensors	Category	Article	Year	Application name	Features
Cameras	Farming	[13]	2014	n/a	Pictures of leaves are taken, then processed, and sent to labs for further disease diagnosis
Cameras	Farming	[14]	2013	n/a	Cameras function as soil color sensors
Cameras	Farming	[15]	2013	iDee	Photographs of the River Dee are captured for water condition assessment
Cameras	Farming	[15]	2013	SOCiT	Photograph of the soil of interest is captured for topsoil organic matter and carbon content prediction
Cameras	Farming	[8, 16]	2013	n/a	Brightness is analyzed for estimating light radiation on plants
Cameras	Farming	[8, 16]	2013	BaiKhaoNK	Pictures of rice leaves are taken to analyze chlorophyll contents
Cameras	Farming	[8, 16]	2013	n/a	Pictures of fruits under white and UV-A light sources are taken to determine ripeness levels for green fruits
Cameras	Farming	[9]	2013	PocketLAI	Images of leaf canopy are acquired to estimate Leaf Area Index (LAI), which in turn gives crop water requirements
Cameras	Farming	[17]	2012	BaiKhao	Pictures of rice leaves are taken to analyze chlorophyll contents
Cameras	Farm management	[18]	2014	n/a	A short video of water flow is taken and then analyzed to estimate the water level, surface velocity, and discharge rate
Cameras	Farm management	[19]	2013	MapIT	Images of object/area of interest are captured for geographic information collecting purpose
Cameras	Information systems	[20]	2014	VillageTree	Farmers take pictures of pest and send to the central server, where the images are processed to analyze types of pests
Cameras	Extension services	[21]	2013	Agricultural Advisory System (AAS)	Images of any infestation or potential problem are captured and sent to the operator’s dashboard in real-time using Pest and Disease Image Upload (PDIU) feature, because sometimes it is difficult to find words to describe the problems
Cameras	Extension services	[22]	2012	m-Sahayak	Images and videos of the diseased plants are captured and sent to the central server for agricultural scientists to inspect and provide solution
Cameras	Extension services	[23]	2012	GeoFoto	Images of land plots are taken by technical staffs and sent to the central office as a verification that the land has been visited
Cameras	Extension services	[24]	2011	mKRISHI	Images and videos can be sent along with a farmer’s query to an expert to seek advice
GPS	Farming	[25]	2013	Magri	GPS locations are used to generate location-aware pest/disease alerts to farmers
GPS	Farming	[15]	2013	SIFSS	Soil characteristics and information, such as pH, soil carbon, N, P, and K, are delivered based on users’ GPS locations in Scotland
GPS	Farming	[15]	2013	iDee	Users can view location-based river conditions in the River Dee catchment based on their GPS positions
GPS	Farming	[15]	2013	SOCiT	User’s locations are used to imply elevation, climate, and geology based on available digital maps and then to predict topsoil organic matter and carbon content
GPS	Farming	[26]	2011	RaGPS	Based on GPS data, the application calculates the extraterrestrial solar radiation and other parameters related to solar position in real-time
GPS	Farm management	[27, 28]	2013, 2014	iFarm	The application sends location-aware task lists to farmers on the field
GPS	Farm management	[29]	2013	n/a	Working patterns of farmers and frequency of visiting certain plot of the farm can be inferred based on GPS locations in the field
GPS	Farm management	[30]	2013	SafeDriving	GPS coordinates of tractor rollover accidents are reported
GPS	Farm management	[19]	2013	MapIT	Images of object/area of interest are mapped for geographic information collecting purpose
GPS	Information systems	[31]	2014	n/a	Location of the user is sent to the central server, which sends only the relevant information about that location back to the user
GPS	Information systems	[20]	2014	VillageTree	Application user can report pest outbreak with the device location. The information is processed and a prediction is sent to users whose location might be invaded by the pest
GPS	Information systems	[32]	2010	SMILEX	Field worker’s fire blight report from the field is coupled with the location data, so the incident report can be shown on the map for better fire blight management
GPS	Extension services	[21]	2013	Agricultural Advisory System (AAS)	Field workers use GPS data to record farm locations when registering farmers. Spatial data (farm plots with water bodies, drainage and irrigation channels) are included in the farmer’s record
GPS	Extension services	[23]	2012	GeoFoto	GPS data is used to verify that the correct land is visited
Microphone	Farm management	[29]	2013	n/a	The application determines usage of different agricultural machines (e.g., tractor and chopper) by sound data
Microphone	Farm management	[19]	2013	MapIT	Microphone is used to annotate images of object/area of interest via speech recognition for geographic information collecting purpose
Microphone	Extension services	[22]	2012	m-Sahayak	Farmers can use the microphone to record their voiced questions to send to agricultural scientists
Microphone	Extension services	[24]	2011	mKRISHI	Audio queries can be recorded and sent to experts
Accelerometer	Farming	[9]	2013	PocketLAI	The application obtains the angles of smartphones as the devices are rotating in order to estimate LAI when the gap fraction is precisely measured at 57.5°, a directional view angle that has been shown in the agricultural research to allow the estimation of LAI to be free from leaf angle distribution and leaf degree clumping
Accelerometer	Farm management	[29]	2013	n/a	Accelerometer is used to detect various body movements in order to identify farm workers’ activities
Accelerometer	Farm management	[30]	2013	SafeDriving	Accelerometer is used to obtain a roll angle and pitch angle of the tractor in order to detect a rollover event
Gyroscope	Farm management	[30]	2013	SafeDriving	Gyroscope is used to obtain a roll angle and pitch angle of the tractor in order to detect a rollover event
Inertial sensors^a	Farm management	[19]	2013	MapIT	Based on the data from inertial sensors, the distance of the object from the camera, and GPS location, the coordinates in the photo are projected to real-world coordinates, yielding a geo-object of exact original geometry

^aThe paper did not mention the specific name of the sensors used. Generally, the term inertial sensors is used to collectively refer to accelerometers and gyroscopes [33].