Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-1

ECE-1467ECE-1467Subsurface ImagingSubsurface Imaging

Course NotesCourse NotesPart 5: Lab ExperimentsPart 5: Lab Experiments

Profs. Brooks and DiMarzio

Northeastern University

Spring 2004

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-2

HOSIS Instrumentation Block HOSIS Instrumentation Block DiagramDiagram

Computer System with Video Board

Processed Images

Tunable FilterSee SupplementaryNotes

CCD Camera

Halogen Lamp

Target Tissue

Thanks to Peter Dwyer atLucid Technologies, MGH, and NU

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-3

Hyperspectral ImagerHyperspectral Imager

Camera

Filter (Polarized Input)

Object Plane

Light Source(Quartz-HalogenThrough Fiber)With Polarizer

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-4

Why Polarized Light?Why Polarized Light?Single Scatter tends toPreserve Polarization

(Not always, of course) Vert

Vert

Hor

Hor

Multiple Scatter tends toDestroy Polarization

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-5

Live-Capture ModeLive-Capture Mode

Frame the Picture Adjust Exposure Monitor Zeros

– Shown in Blue

Monitor Saturation– Shown in Pink

Signal Voltage

2N-1

0

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-6

HSI ProgramsHSI Programs

An Introduction to the tools used for Hyperspectral Imaging

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-7

Frame GrabberFrame Grabber

GUIAllows user to input starting and final

wavelengths, steps between and average pictures per.

Shows real time images for target alignment and focusing

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-8

Frame Grabber ScreenshotFrame Grabber Screenshot

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-9

qFinderqFinder

The Q Finder measures pixel values for the user defined bandwidth and adjusts attenuation where needed.

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-10

qFinder function call and qFinder function call and ScreenshotsScreenshots

qFinder(target_count, start, step, stop)qFinder(200,400,10,720)

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-11

hsi3hsi3

Shows cross sections of the HSI data cube, and measures reflectance spectrum for selected regions.

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-12

hsi3 function call and hsi3 function call and ScreenshotScreenshot

Hsi3(data, wavelengths, hilimit)hsi3(Whole_Image,wavelength_list, 1)

400 500 600 7000

0.2

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column141, row243

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CD+MK HSI3-rev1.01 for Matlab 6p1: 16

=550

200400

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column141

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100200300400

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Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-13

MATLAB Command LinesMATLAB Command Linesfgfg;

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 containingthe 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.

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-14

More MATLAB Command More MATLAB Command LinesLines

showmepics(elk,255);

imagesc(squeeze(elk(:,:,3));

axis image; colorbar;

Matlab function to show an image as a function of x and yfor 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.

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-15

A Sample Run: CollectionA 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

Jan 03 C. DiMarzio/M. Costanzo, NU 10471-5-16

A Sample Run: ProcessingA 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 thereflectance

Max value “should”be 1.0?

Instead, Use dark=-23;