**6.2 SAR basics**

468 Advances in Wavelet Theory and Their Applications in Engineering, Physics and Technology

**Mean Square Error Rate** 

0 5 10 15 20

Image3 Image2 Image1

**Range of Values** 

The wavelet transform is computed separately for different segments of the time-domain signal at different frequencies. Discrete wavelet transform (DWT), which transforms a discrete time signal to a discrete wavelet representation. The reconstruction of image is far better in wavelet by analysis and it is implemented with the given SAR image. Some of the

**MSE** of an estimator is one of many ways to quantify the amount by which an estimator

**PSNR -**This ratio is often used as a quality measurement between the original and a compressed image. The higher the PSNR, the better the quality of the compressed or

The *Mean Square Error (MSE)* and the *Peak Signal to Noise Ratio (PSNR)* are the two error metrics used to compare image quality. The MSE represents the cumulative squared error between the compressed and the original image, whereas PSNR represents a measure of the

From the above got results the coiflets of wavelet denoising method out performs the rest of the wavelet families. This study presented an analysis and comparison of the wavelet families using for image denoising considering PSNR and visual quality of image as quality measure. The effects of bio orthogonal , Reverse bio orthogonal, Daubechies, coiflets and symlets wavelet families on the test images have been examined. The PSNR and visual image quality for wavelet functions of each family is also presented. The PSNR is taken as the objective measure for performance analysis of wavelets using for images denosinig. Here it is analyzed –the results for a wide range of wavelets families and found that the wavelet coifilets provides best performance for SAR images.The computational time required for the Bio orthogonal and reverse bio orthogonal wavelet families is more in comparison to other wavelet families is more in comparison to other wavelet families. The performance of wavelet function depends not only size of the image but also on the content

Fig. 8. MSE values for shrinkage method based on coiflet Wavelet family

parameters taken for analysis of wavelet on SAR images are Mean Square error rate - MSE is called **squared error loss**.

differs from the true value of the quantity being estimated.

peak error. The lower the value of MSE, the lower the error.

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reconstructed image.

**Shrinkage Methods** 

ighshrink

Surelet

Satellite-based Synthetic Aperture Radar (SAR) provides a powerful vessel surveillance capability in front of time consuming traditional methods. SAR images are larger in volume. SAR images typically consist of 32 bit complex pixels with large dimensions. The entropy of SAR images is higher than optical images (Sery et al., 1996).. SAR images carry information in low frequency bands as well as high frequency bands. SAR images have larger dynamic range than optical images. SAR sea images are highly heterogeneous and this fact affects to the viability of the approach. The major advantages of SAR are (i)Sensitive to texture (ii) Good for vegetation studies (iii) Ocean waves, winds, currents(iv) Seismic Activity and Moisture content.
