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VISUALIZATION OF HYPERSPECTRAL IMAGES. ROBERTO BONCE & MINDY SCHOCKLING iMagine REU Montclair State University. Presentation Overview. Hyperspectral Images Wavelet Transform Denoising MATLAB code and results Future Work References. What are hyperspectral images?.
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VISUALIZATION OF HYPERSPECTRAL IMAGES ROBERTO BONCE & MINDY SCHOCKLING iMagine REU Montclair State University
Presentation Overview • Hyperspectral Images • Wavelet Transform • Denoising • MATLAB code and results • Future Work • References
What are hyperspectral images? • Most images contain only data in the color spectrum • Hyperspectral images contain data from several, continuous wavelengths • Our camera records data from 400nm to 900nm
Hyperspectral cont. • Hyperspectral images can be thought of as being stacked on top of each other, creating an image cube • This creates a pixel vector, the vector can be used to distinguish one material from another
Wavelets: “small waves” • Decay as distance from the center increases • Have some sense of periodicity • Can perform local analysis unlike Fourier
Wavelet Analysis and Reconstruction • Original signal is sent through high and low pass filters • Approximation: low frequency, general shape • Detail: high frequency, noise • Reconstruction involves filtering and upsampling
The Project • Analyzing hyperspectral signatures for image analysis can be very computationally expensive • An alternative approach is to select a subset of the images and apply a weighting scheme to generate a useful image
Project Cont. • The plant to the right contains both real and artificial leaves • Goal: distinguish between real and artificial leaves
Last Year (2007) • Focus bands were chosen • Applied a weighting scheme • To give infrared data more importance because the visual data is too similar • An RGB composite image is created
Last Year • Composite image to the right • They used the distance series
Preliminary results • Tried weighting, wavelet transform, different focus bands. • Results were somewhat disappointing
Procedure • Artificial leaves have a second peak in near-infrared region • By centering a focus band in this region, real and artificial leaves can be visualized
Results Original Image (R:60, G:30, B:20) Band-Shifted Image (R:90, G:30, B:20)
Future Work • Further explore the use of wavelets for denoising data • Continue to investigate various weighting schemes • Attempt to classify or distinguish between other materials besides leaves
References: • http://www.microimages.com/getstart/pdf/hyprspec.pdf • Images from http://www.wikipedia.org/ • MATLAB help