AUTOMATED POWER CONTROL FOR MOBILE LASER SPECKLE IMAGING SYSTEM
IMSIYA.K.A ECE , S7 REAHEEC021
GUIDED BY LECT: AMRUTHA ECE DEPT
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
PROBLEM STATEMENT • Power consumption is very large in continuous (always –on operation) mode in LSI
RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
ABSTRACT • Laser speckle imaging (LSI) has been applied to measuring blood Perfusion in human skin. • To reduce the size of LSI to mobile platform, we propose pulsed operation using new APC • Reduced power consumption keeps: →Temperature of case low →Increasing the stability of the system RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
TABLE OF CONTENTS 1. Introduction 2. Operations of laser 3. Laser speckle imaging 4. Schematic diagram of LSI 5. Block diagram of mLSI 6. Automated Power Control 7. Evaluation of APC 8. Conclusion 9. Advantages 10.Disadvantages 11.Future scope 12.References RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
INTRODUCTION • optical power is proportional to the case Temperature of the diode • Optical wavelength depends on case temperature of laser diode
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
OPERATIONS OF LASER • CONTINUOUS WAVE (CW) OPERATION:→Output power is constant →High power consumption • PULSED LASER OPERATION:→Optical power appears in pulse →Lower power consumption RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
LASER SPECKLE IMAGING (LSI) • LSI is a non-invasive blood flow imaging technique • It can provide information on the state of biological tissue and the efficiency of treatment • Attractive features:Temporal resolution Simple instrumentation RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
SCHEMATIC DIAGRAM OF LSI
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
BLOCK DIAGRAM OF MLSI
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
AUTOMATED POWER CONTROL (Schematic of APC)
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
Cont…... • Two latencies are introduced by the pulsed operation mode:-Circuit response time to the pulse source -The turn-on delay of laser diode
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
EVALUATION OF APC • Done in an in-vitro biological tissue phantom
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
Cont‌..
Fig:- Evaluation result: (a) power consumption comparison of AO mode and PO mode. (b) Temperature change of AO mode and PO mode.
RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
Fig - Raw images and SFI map from AO mode and PO mode for 10ms exposure time: (a) raw image of AO mode, (b) SFI map of AO mode, (c) raw image of PO mode, (d) SFI map of AO mode
RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
CONCLUSION • Pulsed laser operation using automated power control circuit in LSI is equivalent to using continuous wave operation • Pulsed laser operation have an advantage of 38% lower power consumption as compared to continuous wave operation • This circuit is applicable to mobile devices with an integrated coherent light source RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
ADVANTAGES • Large field of view allows for a very large area of blood vessel interrogation • Can be useful for evaluating the extent and efficiency of non invasive Melanoma treatment • Lower power consumption
RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
DISADVANTAGES • Not very useful for diagnosing melanoma by itself • Not very useful for quantifying or qualifying chromophores in tissues
RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
FUTURE SCOPE • Can develop real three dimensional vibration mode visualization system based on laser speckle interference
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
REFERENCES [1] K. Petermann, Laser Diode Modulation and Noise. Norwell, MA:Kluwer, 1988, ch. 4. [2] H. Adachi, S. Kamiyama, I. Kidoguchi, and T. Uenoyama, “Self-sustained pulsation in 650nm-Band AlGaInP visible-laser diodes with highly doped saturable absorbing layer,” IEEE Photon. Technol. Lett., vol. 7, no. 12, Dec. 1995. [3] Red Laser Diode DL-6147-040 ver. 2, Sanyo, May 2005. [4] A. F. Fercher and J. D. Briers, “Flow visualization by means of singleexposure speckle photography,” Opt. Commun., vol. 37, no. 5, Jun. 1981. [5] K. R. Forrester, J. Tulip, C. Leonard, C. Steward, and R. C. Bray, “A laser speckle imaging technique for measuring tissue perfusion,” IEEE Trans. Biomed. Eng., vol. 51, no. 11, Nov. 2004. [6] B. Choi, J. C. Ramirez-San-Juan, J. Lotfi, and J. S. Nelson, “Linear response range characterization and in vivo application of laser speckle imaging of blood flow dynamics,” J. Biomed. Optics, vol. 11, no. 4, p.041129, Jul. 2006. [7] J. C. Ramirez-San-Juan, R. Ranos-Garcia, I. Guizar-Iturbide, G. Martinez-Niconoff, and B. Choi, “Impact of velocity distribution assumption on simplified laser speckle imaging equation RCET CHIRAMANAGAD
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SEMINAR PRESENTATION 2010
Automated Power Control For Mobile Laser Speckle Imaging System
IMSIYA.K.A
Thank you……
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SEMINAR PRESENTATION 2010