A Review on Various Plantar Pressure Measurement Systems

Foot plantar pressure is the study of pressure fields acting between the plantar surface of the foot and a supporting surface during everyday locomotion. Such plantar pressure information has proven to be useful in the diagnosis and management of pressure related foot problems, sport mechanics, footwear design, injury prevention and other applications. This paper reviews various foot plantar pressure measurement systems used for different applications. New innovative applications are human identification, biometric, monitoring posture allocation and rehabilitation support system. Gait analysis researchers are focusing on designing systems for uninterrupted measurement of real lif which is important in understanding the effect of daily activities on health. The ideal system to achieve this would be mobile, un-tethered, placed in the shoe sole and able to measure plantar pressure effectively in the targeted environment.


INTRODUCTION
Feet provide the primary surface of interaction with the environment during locomotion therefore it is important to diagnose foot problems at an early stage for injury prevention, risk management and general wellbeing. Examining foot plantar pressure characteristics is one approach to measuring foot health and widely used in various applications. It is, therefore, important that to develop an accurate and reliable foot plantar pressure measurement systems. @ IJTSRD | Available Online @ www.ijtsrd.com | Volume -2 | Issue -2 | Jan-Feb Foot plantar pressure is the study of pressure fields acting between the plantar surface of the foot and a supporting surface during everyday locomotion. Such information has proven to be useful in the diagnosis and management of pressure related foot problems, sport mechanics, footwear design, prevention and other applications. This paper reviews various foot plantar pressure measurement different applications. New innovative applications are human identification, biometric, monitoring posture allocation and rehabilitation support system. Gait analysis researchers are focusing on designing systems for uninterrupted measurement of real life parameters which is important in understanding the effect of daily activities on health. The ideal system to achieve this tethered, placed in the shoe sole and able to measure plantar pressure effectively in the pressure sensor, Feet provide the primary surface of interaction with the environment during locomotion therefore it is important to diagnose foot problems at an early stage for injury prevention, risk management and general wellbeing. Examining foot plantar pressure cteristics is one approach to measuring foot health and widely used in various applications. It is, therefore, important that to develop an accurate and reliable foot plantar pressure measurement systems.
The development of miniature, lightweight, and energy efficient circuit solutions for healthcare sensor applications is an increasingly important research focus given the rapid technological advances in healthcare monitoring equipment, microfabrication processes and wireless communication. Typical applications are footwear design, sports performance analysis and injury prevention, improvement in balance control, and diagnosing disease. More recently innovative applications have also been made to human identification, biometric, monitoring posture allocation and rehabilitation support systems.
Foot pressure measurement can be measured in two manners: static and dynamic. Static measurements are taken`while the patient is standing and dynamic measurements are taken during locomotion. With static measurement, it is not possible to determine the form or loading pattern of the foot during function. Dynamic measurements are used to determine loading during the actual stance phase of gait, quantified by parameters such as the length of stride, angle of gait and speed of gait, along with many other parameters [11].
The plantar pressure sensing systems commercially available on the market or in research laboratories vary in sensor configuration to meet different application requirements. There are several plantar pressure measurement systems, which can be mainly divided into two categories, i.e., platform systems and in-shoe pressure measurement systems [9]. The development of miniature, lightweight, and rgy efficient circuit solutions for healthcare sensor applications is an increasingly important research focus given the rapid technological advances in healthcare monitoring equipment, microfabrication processes and wireless communication. Typical tions are footwear design, sports performance analysis and injury prevention, improvement in balance control, and diagnosing disease. More recently innovative applications have also been made to human identification, biometric, monitoring posture n and rehabilitation support systems.
Foot pressure measurement can be measured in two manners: static and dynamic. Static measurements are taken`while the patient is standing and dynamic measurements are taken during locomotion. With it is not possible to determine the form or loading pattern of the foot during function. Dynamic measurements are used to determine loading during the actual stance phase of gait, quantified by parameters such as the length of stride, angle of gait eed of gait, along with many other parameters The plantar pressure sensing systems commercially available on the market or in research laboratories vary in sensor configuration to meet different application requirements. There are several plantar essure measurement systems, which can be mainly divided into two categories, i.e., platform systems and shoe pressure measurement systems [9]. In-shoe foot plantar pressure measurement syetem provide better efficiency, mobility, flexibility and reduced cost measurement systems. For the system to be mobile and wearable for monitoring activities of daily life, the system should be wireless with low power consumption. An on-chip antenna is a practical solution for compact, low cost and for short-range wireless applications because on-chip antenna is feasible with the assistance of rapid scaling of complementary metal-oxide-semiconductor (CMOS) technology.  [2] developed an in-shoe plantar pressure measurement and analysis system. This system was usedfabric pressure sensing array. They used soft, light weight and high pressure sensitivity textile fabric sensor array. The sensors were connected with a soft polymeric board through conductive yarns and integrated into the insole. A stable data acquisition system was interfaced with the insole. The data was wirelessly transmitted to remote receiver through Bluetooth path. The system was interfaced with desktop, laptop and smart phone and was able to calculate parameters such as mean pressure, peak pressure, centre of pressure (COP) and shift speed of COP. The results were presented for both static and dynamic measurement conditions.

II. LITERATURE SURVEY
S. Ryan Edgar, Timothy Swyka, George Fulk and Edward S. Sazonov [2010] [3] developed a wearable shoe for rehabilitation of stroke patients. This wearable system is based on the combination of an inshoe sensors and a smartphone, and was designed to operate in free living conditions. The data was collected from a sensor device, used for automatic recognition of postures and activities, characterization of extremity use. And provide behavioral enhancing feedback to patients recovering from a stroke. Edgar et al. claim that the system had 99% accuracy in the classification. Thomas Holleczek, Alex Ruegg, Holger Harms, Gerhard Troster [2010] [4] developed "SnowPro", a wearable sport trainer, capable of supporting snowboarders in improving their skill. The system is able to analyze the dynamics of the weight distribution inside the boots. This type of information is essential for identifying the wrong weight shifting techniques, which usually lead to painful crashes in snowboarding sport. The system gives feedback to the user in real-time or after the activity about user performance and support user during learning process. They used three textile integrated pressure sensors, six capacitance-to-digital converters and a Bluetooth module. Besides that, for sport applications the system should not disturb the athlete"s movement but this system utilized off-the-shelf equipment that is usually very bulky therefore system is not very practical.
Yong Feng, Yunjian Ge, Quanjun Song [2011] [5] proposed dynamic plantar pressure for human identification using an in-sole pressure sensor. They recorded the dynamic pressure data during walking and removed noise of the data using the wavelet transform. They compared the pressure at different positions of key points then identified and classified them using a support vector machine (SVM) running on a PC. The system uses wire to transfer data from the sensor to a data acquisition card on a PC and it is reported that the system has 96% identification accuracy.
Edward S. Sazonov, James Hill, Yves Schutz, and Raymond Browning [2011] [6] proposed a shoe-based wearable system for monitoring of posture allocations and activities. Monitoring of posture allocations and activities gives accurate estimation of energy expenditure and may aid in obesity prevention and treatment. Many of the existing techniques to recognize postures and activities rely on a multitude of sensors distributed on the body but using multiple sensor locations is the individual burden for everyday use. This paper presented a wearable shoe-based device and related pattern recognition methodology for automatic recognition of six different postures and  [9] presented a new design of a plantar pressure monitoring system in the form of a smart sock for sensing abnormal changes in the wearer's foot pressures. Authors' group developed a textile-integrated pressure sensor matrix which was knitted inside the sock itself, and RFID technique was applied to collate the sensed readings. With a battery-free design, this system can be powered solely by radio frequency (RF) energy harvested from radio frequency identification (RFID) reader unit hosted on a smartphone of the wearer.
They assembled control unit of the smart sock on a flexible printed circuit board (FPC).

III. CONCLUSION
This paper has reviewed major foot plantar pressure measurement systems available in the market and reported in the current literature. In designing of plantar pressure measurement systems, the main requirements are accuracy, sensitivity, spatial resolution, sampling frequency and calibration. It is important that the system should be mobile and wearable for monitoring activities of daily life, for that the system should be wireless with low power consumption also. Wireless in-shoe foot plantar measurement systems have potential application to better data transfer communication systems, small sized biomedical sensors and other uses.