Sarthak Pati1, Deepak Joshi2, Ashutosh Mishra2 and Sneh Anand2

1 – Dept. Of Biomedical Engineering, Manipal University2 – Center for Biomedical Engineering, IIT – Delhi

ContentsIntroduction to EMG and its acquisitionImportance of EMGPre – Processing of EMG signalsFeatures under considerationClassifier design

What is EMG ?It is a signal used to evaluate the electrical

activity produced by skeletal muscles.

Fig 1 : EMG Signal of Healthy Subject

Block Diagram

EMG Surface Electrodes

Image Courtesy : Orthotics and Prosthetics Lab, BME Unit, AIIMS

Fig 2 : EMG Surface Electrodes

Electrode Placement

Image Courtesy : Orthotics and Prosthetics Lab, BME Unit, AIIMS

Fig 3 : Electrode Placement Diagram

Importance of EMGDiagnosis of

1. Neuro - Muscular Disorders2. Motor Control Disorders3. Prosthetic Control

Sensing of Isometric Motor Activity (motion–less gestures)

Flight control (Human Senses Group, NASA)Machine–Human Interfacing (Advanced Robotics,

MIT)

Why EMG for this study ?Relatively easy to acquire and processIf properly utilised, gives good accuracy for

control systemsHigh sensitivitySingle Muscle Recording PossibleAccess to Deep MusculatureLittle cross – talk concern

EMG – Signal Processing

Fig 4 : Frequency Response of Band Pass Filter

Feature SelectionCriteria :

1. Computational Efficiency

2. High separability with respect to locomotion modes

Classifier DesignObtaining LDA Transformation Matrix TEach Locomotion Mode mapped to a single

dimension data set using TThreshold – based approach for classification

Results

Fig 5 : LDA classification between all the four locomotion modes

Continued…

Fig 6 : LDA classification between FW and SW

References Deepak Joshi, Sneh Anand - Study of circular cross correlation and phase lag to

estimate knee angle: an application to prosthesis; Int. J. Biomechatronics and Biomedical Robotics [in press]

Hargrove L. J., Huang H., Schultz A. E., Lock B. A., Lipschutz R., Kuiken T. A. - Toward the Development of a Neural Interface for Lower Limb Prosthesis Control; Delsys Prize Winner

Parker P., Englehart K., Hudgins B. - Myoelectric signal processing for control of powered limb prostheses; Journal of Electromyography and Kinesiology

Englehart K., Hudgins B. - A Robust, Real-Time Control Scheme for Multifunction Myoelectric Control; IEEE Transactions on Biomedical Engineering, Vol.50, No.7

Chan F.H.Y., Yang Y.S., Lam F.K., Zhang Y.T., Parker P.A. - Fuzzy EMG Classification for Prosthesis Control; IEEE Transactions on Rehabilitation Engineering, Vol.8, No.3

Englehart K., Hudgins B., Parker P., Maryhelen S. - Time-Frequency Representation for Classification of The Transient Myoelectric Signal; 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vol. 20, No 5

Phinyomark A., Limsakul C., Phukpattaranont P. - A Novel Feature Extraction for Robust EMG Pattern Recognition; Journal of Computing, Vol 1, Issue 1, ISSN: 2151-9617

Thank You

Any questions…?