基于小波变换的微光图像降噪方法研究
关键词 EMCCD 椒盐噪声 图像滤波 硬阈值 小波变换
毕业论文设计说明书（论文）外文摘要
Title LLL image noise reduction method research based on wavelet transform
Abstract
Noise is the key factor affecting the quality of the digital image, so the digital image denoising is particularly important. This paper studies thresholding problem based on wavelet transform. First ,this paper introduced the principle of EMCCD imaging and image noise and filtering method, and introduces the principle of digital image system briefly. This paper presents an algorithm based on wavelet transform hard threshold function analyzes the algorithms and workflows, and provided examples of its filtering characteristics. The simulation and experimental results show that when in high noise density is low, the performance of the proposed algorithm based on wavelet transform hard threshold function was significantly better than the other filter, and with the noise density increases, the performance is relatively stable. The peak signal to noise ratio of the image increases at different noise density .And the results achieved the expected goals.
Keywords EMCCD salt and pepper noise image filtering Hard threshold Wavelet Transform
目 录
1 绪论 1
1.1 引言 1
1.2 本课题研究的意义 1
1.3 本课题研究背景及现状 1
1.4 本文内容安排和研究内容 2
2 EMCCD的工作原理和噪声模型 3
2.1 EMCCD组成及工作原理 3
2.2 EMCCD噪声特性 4
3 基于小波变换的微光图像降噪算法研究 5
3.1 EMCCD噪声分布模型 5
3.2 数字图像降噪技术 5
3.3 小波阈值降噪理论的研究 7
3.4 小波阈值去噪方法 8
3.5 阈值函数和阈值估计 8
3.6 小波阈值去噪算法 11
3.7 仿真及结果分析 12
结 论 19
致 谢 20
参考文献21
1 绪论
1.1 引言
微光夜视技术是研究在夜天或者低照度下获取目标信息的技术。利用这一技术，通过各种微光图像增强器和CCD的成像装置，将各种不能轻易被人眼反应的景物图像，使人眼可以看得到，从而弥补了人眼直接对这些景物图像观测局限性，扩展了人的视野和功能。
但是，通常我们通过各种器件所获得的数字图像会在各种过程中不可避免的收到噪声的干扰。为了更好的获得所需的图像信息，需要对获取的噪声图像进行降噪处理。数字图像处理是利用数字计算机对数字图像进行处理。将通过器件获得的图像进行处理而得到达到人们要求质量的图像是图像处理的任务和目标。