The Research On Retinex Theory And The Application In License Plate Recognition System

This paper mainly studies image enhancement problem in traffic scene under thecondition of weak light or at night, on the basis of comparing the traditionalenhancement algorithms and Wavelet transformation, uses the Retinex theory toresearch this problem. The Retinex theory is based on adjusting human visual systemand perceiving object color and luminance model, which is proposed as imageintensification theory. It has these excellences such as compressing the dynamic rangeof the image availably, advancing the contrast of the image, preserving the details inshadow of the image and colors constancy.This paper have already implemented two kinds of classical algorithms,surround-based image enhancement method and a variational model for the Retinex,and compare the capabilities of the algorithms by several correlative targets. Then usea kind of advanced multi-scale Retinex algorithm, reduces the complexity of Retinexalgorithm, perseves color information and contrast of the image. In imageenhancement, due to the variational model based on the Retinex theory, a modificationfor preserving the detail, and then calculates the optimal illumination image bycombining pyramid data structure and lifting algorithm, which reduces thecomputational complexity, and experiments show that this algorithm can effectivelyremove obscuration effect from color images.