WAVELET ANALYSIS OF SPACE SOLAR TELESCOPE IMAGES

Date 10th March 2016

Outline

Solar Space Telescope

Why Data Compression

Wavelet Transform

Need for the wavelet transform

Signal Decomposition using wavelet transform

Future Work

References

SPACE SOLAR TELESCOPE

High resolution telescope send into space for collecting continuous data from sun over broad optical spectrum

Provide data which can be used in outer space whether forecast , advancement in solar physics research

It acquires large quantity(>1500 GB) of raw data every day, which are processed down to relatively lower amount(<50 GB) before sending them to ground

DATA COMPRESSION

The compression of data received by SST is restricted by SNR as well as image that would be obtained after reconstruction

Wavelet Transform provides better image processing and data compression as compared to DCT

WAVELET TRANSFORM

Developed 10 years back and being harnessed in most of signal processing related applications

Multi-resolution analysis ability i.e. local features of signal in both time domain as well as frequency domain can be demonstrated

Signal or images can be compressed in wavelet domain after decomposes them at various scale

Cont…Wavelet Transform involves wavelets for signal analysis instead using any

window as in Short Time Fourier Transform

Each wavelet have different analyzing and compressing ability when applied on same signal

Thus each signal/image should be analyzed with all the available wavelets

SIGNAL DECOMPOSITION USING WAVELET TRANSFORM

ZEROTREE WAVELET IMAGE COMPRESSION

Process

Image compression

Image Recovery

1. The process of

wavelet transform is

to decorrelate the

image, process is

lossless and reversible

if calculating error are

ignored

2.Series of wavelet

coefficient are formed in

transform domain that are

quantized to integer to

code bit stream to be

transmitted/stored

ZEROTREE WAVELET IMAGE COMPRESSION

Quantization used is neither lossless nor reversible however it is key part of image compression

The embedded zerotree wavelet compression scheme with high compression efficiency is used to quantize post-transformation waveletcoefficients

Principle

Results

Original Signal RRReconstructed Signal After

CompressionNoise removed from original image

Results

Original Signal Reconstructed Signal After

Compression

Noise removed from original

image

FUTURE WORK

o To develop mat lab code for compressing the data obtained from Solar Space Telescope

o Compare its efficiency and resolution of reconstructed signal with Compressed Sensing method and Discrete Cosine Transform

References• Signal Processing. (n.d.). Retrieved from http://india.skatelescope.org/sdp/

• https://en.wikipedia.org/w/index.php?title=Astronomical_interferometer&oldid=706945487

• Chin. J. Astron. Astrophys. Vol. 3 (2003), No. 6, 587–596

• https://en.wikipedia.org/w/index.php?title=Interferometry&oldid=706490125

THANK YOU