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Jan 03C. DiMarzio/M. Costanzo, NU10471-5-1 ECE-1467 Subsurface Imaging Course Notes Part 5: Lab Experiments Profs. Brooks and DiMarzio Northeastern University.

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Presentation on theme: "Jan 03C. DiMarzio/M. Costanzo, NU10471-5-1 ECE-1467 Subsurface Imaging Course Notes Part 5: Lab Experiments Profs. Brooks and DiMarzio Northeastern University."— Presentation transcript:

1 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-1 ECE-1467 Subsurface Imaging Course Notes Part 5: Lab Experiments Profs. Brooks and DiMarzio Northeastern University Spring 2004

2 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-2 HOSIS Instrumentation Block Diagram Computer System with Video Board Processed Images Tunable Filter See Supplementary Notes CCD Camera Halogen Lamp Target Tissue Thanks to Peter Dwyer at Lucid Technologies, MGH, and NU

3 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-3 Hyperspectral Imager Camera Filter (Polarized Input) Object Plane Light Source (Quartz-Halogen Through Fiber) With Polarizer

4 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-4 Why Polarized Light? Single Scatter tends to Preserve Polarization (Not always, of course) Vert Hor Multiple Scatter tends to Destroy Polarization

5 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-5 Live-Capture Mode Frame the Picture Adjust Exposure Monitor Zeros – Shown in Blue Monitor Saturation – Shown in Pink Signal Voltage 2 N -1 0

6 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-6 HSI Programs An Introduction to the tools used for Hyperspectral Imaging

7 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-7 Frame Grabber GUI Allows user to input starting and final wavelengths, steps between and average pictures per. Shows real time images for target alignment and focusing

8 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-8 Frame Grabber Screenshot

9 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-9 qFinder The Q Finder measures pixel values for the user defined bandwidth and adjusts attenuation where needed.

10 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-10 qFinder function call and Screenshots qFinder(target_count, start, step, stop) qFinder(200,400,10,720)

11 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-11 hsi3 Shows cross sections of the HSI data cube, and measures reflectance spectrum for selected regions.

12 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-12 hsi3 function call and Screenshot Hsi3(data, wavelengths, hilimit) hsi3(Whole_Image,wavelength_list, 1)

13 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-13 MATLAB Command Lines fgfg; save moose elk caribou wombat load moose hsi3(elk,wavelength_list,255); Run our GUI-based framegrabber program Matlab function to save a file called moose.mat containing the variables elk, caribou, and wombat. Matlab function to load all the variables stored in moose.mat Display the datacube elk, with wavelength_list on the wavelength axis, and a colorbar that goes from 0 to 255.

14 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-14 More MATLAB Command Lines showmepics(elk,255); imagesc(squeeze(elk(:,:,3)); axis image; colorbar; Matlab function to show an image as a function of x and y for the third value of wavelength. Matlab functions to make pixels equal size in both directions and to display a colorbar beside it. Our function to run imagesc on every wavelength. imagesc(squeeze(elk(:,200,:)); Matlab function to show an image as a function of wavelength and y for the 200th value of y.

15 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-15 A Sample Run: Collection fg; id=‘White’ save white Whole_Image wavelength_list id hsi3( Whole_Image,wavelength_list,255); Image the White Standard Check Levels fg; id=‘Moose’ save moose Whole_Image wavelength_list id hsi3( Whole_Image,wavelength_list,255); Image the Object Check Levels

16 Jan 03C. DiMarzio/M. Costanzo, NU10471-5-16 A Sample Run: Processing fg; id=‘Dark’ save dark Whole_Image wavelength_list id Image the Dark Level (Not Used with this camera) load white; white= double(Whole_Image); load moose; moose= double(Whole_Image); load dark; dark= Whole_Image; hsi3(refl,wavelength_list,1.2); Load and Process refl=(moose-dark)./(white-dark); Load ‘em all and give ‘em the right names. Calculate the reflectance Max value “should” be 1.0? Instead, Use dark=-23;


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