1. Measurement of the force applied by a finger-tip on an object using
Magnetic Resonance Imaging.
SID: 200643372,
iMBE, School of Medical Engineering, University of Leeds.
1. Introduction 2. Principle
• Below the digital pulp of the finger lies various sensory receptors such
• Quality of a packaging material can be
as Meissner’s and Pacinian corpuscles (fig 3).
detected by surveying it with one’s finger-
• Activation of these pressure and touch receptors, by the friction
tip.
induced vibrations, provides information about the coarseness of the
• The emotions generated by the roughness or
object the finger is touching (fig 4).
smoothness of the material gives an idea
• The curvature of the digital pulp region, at the point of contact, gives
about the material’s quality.
an idea about the force applied by the finger (fig 5).
• Additional information about the quality of
Fig 1. Commodities that are generally
the product present inside can also be scanned by finger-tips.
http://pollynoble.com/2010/09/cheesey-sweet-potato-crisps-recipe/
gathered.
• The optimum force required to scan the
surface still remains unknown.
• The aim of this poster is to present a Shampoo
possible method to detect the forces applied
by a finger-tip on a packaging material using Fig 5. The action-reaction forces
acting on the finger and producing a
MRI. Fig 2. A shopper using her finger-tips to
sense the quality of a product.
Fig 3. Schematic representation of
different parts of a human finger.
Fig 4. Different sensory receptors curved digital pulp.
http://www.imaginis.com/sports-medicine/orthopedic-mr-
http://www.telegraph.co.uk/news/uknews/2609556/Supermarket- http://visual.merriam-webster.com/human-being/sense-
present under the finger-tip skin. imaging-new-levels-of-diagnostic-information-on-sports-injuries.
http://candacewalraven.wikispaces.com/K.++Sensory+Organs http://myplaceofpeace.blogspot.co.uk/2009/11/empty-shampoo-
price-comparison-Middle-classes-face-their-Ocado-moment.html organs/touch/finger.php
bottle.html
3. Procedure
• Step 1: Attach the packaging • Step 2: Place the experimental set-up inside • Step 3: The lateral MRI image of Concavity
material on the top of the the open-extremity MRI scanner. The finger the finger is then examined and the
aluminium bar and prepare is moved once as shown in fig 6. extent of concavity at the tip of the
the experimental set-up as • The required field strength is about 1.5 finger (shown by a red box in fig Force Applied
shown in fig 6. Tesla and the RF coil can be a quadrature 8) is calculated.
wrist coil. • The deeper the digital pulp is • Step 4: Calculating the force
pushed inside the higher is the applied by the finger
a b depending on the concavity of
force applied by the finger.
the finger-tip. This can be
done with the help of a coding
using a mathematical software
like MATLAB.
• Fast spin echo (FSE) should
be used while capturing the
Fig 8. The area of interest in the MRI image of the finger.
images as this will decrease
http://www.imaginis.com/sports-medicine/orthopedic-mr-imaging-new-levels-of-diagnostic-
information-on-sports-injuries.
Fig 6. The experimental set-up and Fig 7. The open extremity MRI scanners that can be used for the test are (a) E-
the movement of the finger. scanner and (b) C-scanner. the computational errors.
(a) http://www.alakamedical.com/itemdetail.cfm?ProductID=332. (b) http://www.mghradrounds.org/index.php?src=gendocs&link=2009_may.
4. Expected Results
• Force-displacement curve. • Maximum force to be applied • Improved quality of the • A standardised experimental
for the perfect perception. packaging material. method can be generated
Displacement Force Perception Better Soothing
using the results.
• This will make the procedure
quality perception
of the Digital
Fig 9. The Force vs
Pulp.
Displacement
Graph.
Confused. laboratory independent and
None. Larger set the benchmark for the
Force Applied by the finger (N). Revenue Higher Sales maximum force applied.
Perfect.
5. Discussion 6. Conclusion
• The finger will be in motion and hence signal to noise ratio will be low. • Along with visionary perception, the sensation of touch is very
• Packaging materials having magnetic properties can not be used for the important in judging the quality of a packaging material.
test. • Magnetic Resonance Imaging is a non-invasive method of imaging and
• Placing the experimental set-up inside the open-extremity MRI scanner hence no adverse effects are produced on the finger.
will be challenging. Using a C-scan MRI device will be more beneficial • Force measurement can be performed by MRI.
than an E-scan MRI machine. • The knowledge of forces applied by shoppers enables companies to
• Contrast agents and external optical motion tracking cameras might be make better product packaging that are not only soothing to the eye but
needed. also good to touch.
References :
1. Earls, J.P. ‘Digital MRI: The Fingers and Toes.’
2. Fagiani, R., Massi, F., Chatelet, E., Berthier, Y. and Akay, A. ‘Tactile perception by friction induced vibrations.’ Tribology International 44; 2011; 1100-1110.
3. http://www.melbourneradiology.com.au/mri-gallery/mri-fingers-and-toes.html.
4. The, J. and Whiteley, G. ‘MRI of soft tissue masses of the hand and wrist.’ The British Journal of Radiology 80; 2007; 47-63.
5. Zaitsev, M., Dold, C., Sakas, G., Henning, J. and Speck, O. ‘Magnetic resonance imaging of freely moving objects: Perspective real-time motion correction using and external optical motion tracking system.’ NeuroImage 31; 2006; 1038-
1050.