1. Standardized Micro-Scale Mixing Evaluation Guillermo González-Fernández Benjamin Yang

2. Outline Introduction and Motivation Project Goal and Success Measure Raw Images Image enhancement Edge detection Evaluation Results Custom area mixing evaluation

3. Introduction and Motivation Micro scale mixing crucial to success of many fields No standardized comparison Characteristics in microfluidics –Low Reynolds number –Laminar Flow –Diffusion Limited Image: A.D. Strook et al., “Chaotic Mixer for Microchannels,” Science, vol 295, pp. 647-651, 2002

4. Project Goal and Success Measure Evaluate the extent of mixing in standardized experimental images Success will be based on correlation to existing simulation results Standard Y-channelSquare-wave channelCompartment channel

5. Raw Images AB CD EFG

6. Image enhancement (I) Why image enhancement? Better edge detection Study the images: histogram, 2D-DFT… Apply Matlab filters Design new filters: Min, med, max Contraharmonic New gaussian filter (gaussian iterations) Gaussian Sobel Prewitt Laplacian Log Unsharp

7. Image enhancement (II) Min MaxMed ContraharmonicGaussian iterations

8. Image enhancement (III) Cascade different combinations of the filters Final image obtained by averaging best results : –Average-gaussian-average –Average-gaussian-gaussian –Average-gaussian iterations- gaussian –Average-gaussian iterations- average

9. Edge detection We don’t know the real edge!! Matlab edge detection strategies New strategies Y channel: Perfect boundary Square channel: General method

10. Edge detection We don’t know the real edge!! Matlab edge detection strategies New strategies Y channel: Perfect boundary Square channel: General method

11. Evaluation Extract part of the image we will evaluate Estimate mixing percentage

12. Results

13. Custom area mixing evaluation User defines the image to evaluate User defines area (rectangle) to evaluate Obtain mixing efficiency

14. References [1]Bertsch, S. Heimgartner, P. Cousseau, and P. Renoud. “Static micromixers based on large-scale industrial mixer geometry”, Lab on a Chip, Vol 1, pp 56-60, 2001. [2]A.D. Strook et al., “Chaotic Mixer for Microchannels,” Science, vol 295, pp. 647- 651, 2002 [3]R. H. Liu, M. A. Stremler, K. V. Sharp, M. G. Olsen, J. G. Santiago, R. J. Adrian, H Aref, and D. J. Beebe. "Passive mixing in a three-dimensional serpentine microchannel", J. of MEMS, Vol 9, No. 2, pp 190-196, 2000. [4]V. Mengeaud, J. Josserand, and H. H. Girault. “Mixing processes in a zigzag microchannel: finite element simulations and optical study”, Analytical Chemistry, Vol 74, pp 4279-4286, 2002. [5]R. Gonzalez, R. Woods. Digital Image Processing, 2nd Edition. Prentice Hall, Upper Saddle River, N.J, 2002. [6]Kai Kang, R. Chevray. “Visualization of fluid mixing in microchannels”, IEEE Computer Graphics and Applications, Vol 25, Issue 6, pp 16-20, 2005. [7]Leming Shi, Weida Tong, Zhenqiang Su, et al. “Microarry scanner calibration curves: characteristics and implications”, BMC Bioinformatics, Vol 6, pp. 1-14, 2005 [8]Peter A. C. ‘t Hoen, Rolf Turk, Judith M. Boer, et al. “Intensity-based analysis of two color microarrays”, Nucleic Acids Research, Vol 32, No 4, pp. e41-e47, 2004

15. Questions?