A Nonlinear ImageEnhancement Technique for Aerial Imagery by using wavelets

ABSTRACT

In this project , we proposed a wavelet based dynamic range compression algorithm to improve the visual quality of digital images.

INTRODUCTION

Aerial images captured from aircrafts, spacecrafts, or satellites usually suffer from lack of clarity, since the atmosphere enclosing Earth has effects upon the images such as turbidity caused by haze, fog, clouds or heavy rain.

LITERATURE SURVEY

•A new image enhancement algorithm for extremely forextremely high contrast images is presented in thisPaper. The adaptiveness of the transfer function, depending on the mean of each pixel’s neighborhood makes the algorithm more flexible and easier to control[1].•A wavelet based fast image enhancement algorithm which provides dynamic range compression preserving the local contrast and tonal rendition has been developed to improve the visual quality of the digital images[2].

The MSR, comprised of three scales (small, intermediate, and large), was found to synthesize dynamic range compression, color consistency, and tonal rendition, and to produce results that compare favorably with human visual perception, except for scenes that contain violations of the gray-world assumption[3].

APPROACH

The Wavelet based Dynamic Range Compression algorithm(WDRC) consists of three stages:

Histogram adjustment Wavelet based Dynamic Range

Compression and Contrast Enhancement

Color Restoration

Images

IMPLEMENTATION

Language :MATLAB 7.2i

CONCLUSION

The WDRC algorithm in aerial imagery will be implemented such that aerial images show strong robustness, high image quality and improved visibility .

REFERENCES

1.K. V. Asari, E. Oguslu, and S. Arigela, “Nonlinear enhancement of extremely high contrast images for visibility improvement,” LectureNotes in Computer Science, Proc. of the 5th Indian Conference onComputer Vision, Graphics and Image Processing - ICVGIP 2006:(ISBN: 3-540-29643-3), vol.4338/2006, pp.240-251, (2006).

REFERENCES

2.N. Unaldi, P. Sankaran, K. V. Asari, Z. Rahman, “Image enhancement for improving face detection under non-uniform lighting conditions”,ICIP 2008. 15th IEEE International Conference on Image Processing,(2008)

3.A Multiscale Retinex for Bridging the Gap Between Color Images and the Human Observation of Scenes by Daniel J. Jobson, Member, IEEE, Zia-ur Rahman, Member, IEEE, and Glenn A. Woodell, published inIEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 6, NO. 7, JULY 1997.

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