Designing a Robot for Portable Raman Probe Positioning

Designing a Robot for Portable Raman Probe Positioning: The Robo-Scanner

Presentation Outline Objectives u Introduction u Hardware Design u Software Design u Design Alternatives u Problems Encountered u Future Goals u

Main Objectives u u u To design & build a functional prototype that will correctly position raman probe to scan pills & tissue Incorporate Matlab for positioning & data analysis Send Matlab outputs to microcontroller Write & implement Assembly code to translate Matlab code into motor movement Create model of different pill types

Introduction u Raman Spectroscopy [1, 2] • Has numerous medical applications • Physics-based technique that detects chemical composition of a sample • Each chemical has characteristic wavelength shift • Can relate the peaks in a Raman spectrum to specific chemicals & compare composition of a test sample

Two Applications for Portable Raman

Raman Spectroscopy Portable Verax Raman spectrometer made by In. Photonics

Raman Spectroscopy

Main Components u u u u Erector sets Raman probe 68 HC 11 microcontroller Breadboard/circuitry Cameras DC step motors Printer railways

Hardware Design u First Step: • Build gantry frame using erector sets • Purchase & fasten c-channels

Benefits of Gantry Design [3] u u Perform pick & place applications Provide better positioning accuracy Easier to program with respect to motion due to X, Y, Z coordinate system Less limited by floor space constraints

u Second Step: • Disassemble printer components • Mount X & Y railways onto frame Hardware Design …

Hardware Design cont. u Third Step: • • • Create wheel mechanism Mount camera Mount probe on Z-axis Gigaware® 1. 3 MP PC Camera

Mechanical Design DC step motors used from disassembled printers u Change initial design concept of wheel mechanism u • To decrease drag & friction, remove rubber tread • Reposition wheel on top of c-channel instead of inside

Final Product !

Network Overview RS 232 68 HC 11 Breadboard

Microcontroller Diagram

Electrical Components u LM 741 CN Op Amp (All 3 inverting)

Software and Circuit Design

Wiring Diagrams

Software Design u Second Step: Write code using Matlab Toolkits • • • u Wavelets (pre-processing) Statistics Image processing Future Toolkits • Camera calibration ~ 3 D triangulation of 2 images • Image acquisition ~ live video feed

Matlab GUI

Software Design u Imaging Processing Toolkit to position robot • Load video image from file (. jpg) from camera • Convert image to grayscale • Threshold image • Count distinct objects in image • Find center of each distinct object • Convert pixel location to robot location • Send location to HC 11 by serial port

Image Processing Results Original Image (with pills marked) Threshold Image Grayscale Image Count Objects In Image *Results depend on lighting, photo conditions*

Moving the Robot u u u Check to see if starting from home position Move robot from home position to desired pill location Collect spectra (use separate software) Process software and output results Move robot from pill position to home Repeat for next pill

Processing Details u Preprocess Spectra • Background Subtraction • Remove noise • Remove cosmic rays u Principal Component Analysis • Reduce dimensionality of data u Algorithm • Discriminant Function Analysis • Neural Network Analysis

Spectral Results

Testing Assembly Code

Problems Encountered u Consider weight of raman probe in choosing initial robotic arm mechanics Devising efficient pulley system Weight of printer railways & motors High coefficient of friction between wheel & aluminum c-channel Software development & implementation Camera calibration Coordinate triangulation u Time constraints u u u

Design Alternatives Possible Design Improvements: u u u Construct robotic arm Addition of proximity sensors Swap microcontroller for new motion controller Incorporate AC servo motors in place of step motors Autonomous positioning

Future Goals u Expand current design by incorporating more sophisticated technologies • Implement 3 D triangulation using stereo camera calibration • Combine functions with Nurse-Bot or similar application • Use robot for scanning cancerous tissue samples • Optimize portable robot design requirements for OR usage • Telepresence i. e. administer medication

Grand Finale u Final Demo

References [1] Huang, Z. , Mc. Williams, A. , Lui, H. , Mc. Lean, D. I. , Lam, S. and Zeng, H. , Near-infrared Raman spectroscopy for optical diagnosis of lung cancer. Int J Cancer, 2003. 107(6): p. 1047 -52. [2] Cao, A. , Pandya, A. , Serhatkulu, G. K. , Weber, R. , Dai, H. , Thakur, J. S. , Naik, R. , Naik, V. , Auner, G. W. , Rabah, R. , and Freeman, D. C. , A Robust Method for Automated Background Subtraction of Tissue Flourescence. Journal of Raman Spectroscopy, 2006 (in press). [3] http: //www. robots. com/faq. php? question=gantry+robot