超声图像研究去噪法
合集下载
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
6
7
8
9
10
11
Stochastic reconstruction
Erez, Schechner & Adam , Proc. DAGM 2006
1 0.8 White noise 0.6 0.4 0.2
0
r = 7cm
r = 11cm r = 15cm
-2
-1
0
1
2
Radial lag (mm)
Erez, Schechner & Adam , Proc. DAGM 2006
19
Standard Pre-Processing
RF line
Sampling
in tissue
9
Image Formation
Probe
Sector
Radial axis
Sweeping beam
Lateral axis
Erez, Schechner & Adam , Proc. DAGM 2006
Lateral PSF
D
10
D
Low acoustic freq
High acoustic freq
7
Ultrasound Problems
Blurring
Speckle noise
Attenuatio n
Radial axis
Transmitter Receiver
System noise
Erez, Schechner & Adam , Proc. DAGM 2006
Lateral axis
Previous Work
Erez, Schechner & Adam , Proc. DAGM 2006
Wave phenomenon
16
Object
Object blur: Wave interference
as if no interference
Erez, Schechner & Adam , Proc. DAGM 2006
Low acoustic freq
5 6 7 8 9 10 11
High acoustic freq
Erez, Schechner & Adam , Proc. DAGM 2006
Radial distance [cm]
25
Stochastic Freq. Compounding
5
Arithmetic mean
23
Best Linear Unbiased Estimator
Considering noise statistics
Erez, Schechner & Adam , Proc. DAGM 2006
Radial distance [cm]
24
Input: Dual Acoustic Frequency
70s Wiener filter Space invariant
80s Compounding (fNreoqtuuesnincyg &nosipseatsiatal)tistics
86 89 90 95 Late 90s
Weighted median filter (Mcdicken et al.) Local freSqmuoeontchyindgiversity (Forsberg et al.) AnisotroNpoict hdaifnfudsliinogn (aPtetreonnauaantdioMnalik) Non-linear Gaussian filters (Aurich)
Speckle Noise
PSF
D
17
D
Depends on:
• Radial distance • Acoustic frequency
Low acoustic freq
High acoustic freq
Erez, Schechner & Adam , Proc. DAGM 2006
18
Measuring Noise Statistics
Time gain compensation
Envelope detection
Dynamic range compression
20
Speckle Noise
=
log operation Iinear noise
Erez, Schechner & Adam , Proc. DAGM 2006
21
Model
… … …
Erez, Schechner & Adam , Proc. DAGM 2006
correlated noise !!!
y = Hx
22
+n
… … …
Stochastic Reconstrwenku.baidu.comction
Erez, Schechner & Adam , Proc. DAGM 2006
Erez, Schechner & Adam , Proc. DAGM 2006
11
Attenuation
probe
a object
r
distance
Erez, Schechner & Adam , Proc. DAGM 2006
15
Speckle Noise
Low acoustic freq
High acoustic freq
1
Ultrasound Image Denoising
by Spatially Varying Frequency Compounding
Yael Erez , Yoav Y. Schechner , and Dan Adam
Dept. Elect. Eng. Technion – Israel Institute of Technology
HarmoLnoicwimsiaggnianlg
01,04 Wavelets (Insana et al, Loi et al.)
8
Image Formation
probe
Received signal
Erez, Schechner & Adam , Proc. DAGM 2006
Velocity of acoustic wave