摘要本文主要研究了直方图均衡化（Histogram Equalization ，HE）、局部直方图均衡化（Local area Histogram Equalization ,LAHE）在水下图像增强中的应用。21世纪，海洋资源越来越受到人们的关注，人类开始致力于开发利用海洋资源。因此，海洋技术也成为技术重要分支。限制发展在海底时水下图像的问题主要在于在水中光会被吸收或出现散射现象。由于自然光容易被吸收，水下机器人需要携带人造光源以提供充足的照明强度。但是，这些闪光灯更适用于照亮在不均匀场景中的物体，而且随着机器人的移动，导致画面中会出现阴影。本文列出了一些现有的方法来解决当处理水下图像序列时低对比度、非均匀照明带来的问题。68289

    为了使获得的图像清晰度，我们利用现有的图像处理技术对水下图像进行增强。从图像处理的作用域出发，图像增强可分为空域增强方法和频域增强方法。小波变换属于频域增强，HE和LAHE则属于空域增强。

    本文主要介绍这两种图像技术来处理图像，通过对这几种算法对图像进行仿真，得到处理后的清晰图像。最后对这几种处理方法进行比较，能更好的认知这几种方法的优劣。

毕业论文关键词：图像技术；水下图像；直方图均衡化；局部直方图均衡化； 

Abstract The Simulation and Analysis of Local Histogram Equalization in Underwater Images

    This paper mainly studies the application of the histogram equalization (HE), local area histogram equalization (LAHE) in underwater image enhancement. In the 21st century, the ocean resources get more attention than before, humans begin to devote more time on the ocean resources. Therefore, the ocean technology has also become an important branch of the technology revolution. A major obstacle to processing images of the ocean floor comes from the absorption and scattering effects of the light in the aquatic environment. Due to the absorption of natural light, underwater vehicles often require artificial light sources attached to them to provide the adequate illumination. But the flash is more applicable to illuminate the scene in a non-uniform fashion, and as the movement of the robot, the picture will produce shadows. This paper lists some existing methods to solve the problems of low contrast and non-uniform illumination which will appear  when dealing with underwater image sequence.

    In order to make the image more clear, existing image processing technology is used to enhance underwater images. Image enhancement can be pided into the method of airspace enhancement and the method of enhancement in the frequency domain due to The scope of the image processing. The wavelet transform belongs to the method of enhancement in the frequency domain, and the histogram equalization (HE), local area histogram equalization (LAHE) belongs to the method of airspace enhancement.

    This paper mainly introduces the two kinds of image technique to process image. Through the simulation of image, more clear image can be got after processing. Finally, this paper carries on the comparison to the several processing methods, acknowledging the strengths and weaknesses of these methods.

Keywords: Image technology；Underwater image； Histogram equalization；Local area histogram equalization；

目录

第一章 绪论 1

1.1 引言 1

1.2 研究历史和现状 1

1.3 本文主要工作和内容安排 2

第二章 图像增强技术 4

2.1 图像增强技术简介