Strain Variation for B-Mode Image 葉文俊 呂仁碩 李承諺

Previous Work - Block Size - Multi-Level Speckle Tracking Correction Improve Speckle Tracking Correction - Block Size - Multi-Level Speckle Tracking Correction Improve Elastic Image Resolution - Strain - Shorten、Elongation - Direction

Displacement and Strain Our approach x1 x1+d x d1 Origin： After Strain d2

Result Thyroid Image Strain Image Image Size：450 X 450 pixels Block Size：50 X 50 pixels Thyroid Image Strain Image 2 4 6 8 10 12 14 16 18 20 22

Trade-Off If strain variation between images is increased, speckle correlation is decreased and speckle tracking correction is decreased. If strain variation between images is decreased, speckle correlation is increased and speckle tracking correction is increased.

Method nst13 (new speckle tracking between 1st and 3rd images) = st12+st23 ost13 (original speckle tracking between 1st and 3rd images) = st13 1st 2nd 3rd

Result Summation of strain with the 1% strain variation between 2 images. 1-2 1-3=1-2+2-3 1-4=1-2+2-3+3-4 1-5=1-2+2-3+3-4+4-5 1-6=1-2+2-3+3-4+4-5+5-6 1-7=1-2+2-3+3-4+ 4-5+5-6+6-7

Result Summation of strain with the 2% strain variation between 2 images. 1-3 1-5=1-3+3-5 1-7=1-3+3-5+5-7 Summation of strain with the 3% strain variation between 2 images. 1-4 1-7=1-4+4-7

Result Summation of strain with the 1% strain variation between 2 images. Summation of strain with the 2% strain variation between 2 images. 1-7=1-2+2-3+3-4+ 4-5+5-6+6-7 1-7=1-3+3-5+5-7 Summation of strain with the 3% strain variation between 2 images. No summation of strain with the 6% strain variation between 2 images. 1-7=1-4+4-7 1-7

Result (Breast Phantom) Shorten 1-2 1-3 1-4 Elongation 1-2 1-3 1-4

Result (Breast Phantom) X Direction 1-2 1-3 1-4

FFT-based Speckle Analysis 為了解決Speckle tracking所遭遇的問題 : Block size v.s. Resolution Motion 量化誤差 v.s. 內插 Speckle移動距離 v.s. Speckle變形

FFT-based Speckle Analysis 由頻域對B-mode影像進行分析 Z軸方向的一段組織反射信號 z

FFT-based Speckle Analysis 信號與系統理論 ： a(z)  A(ω) a(kz)  A(ω/k) f

FFT-based Speckle Analysis 將此方法推廣至二維 ： 探頭 fz x fx z

FFT-based Speckle Analysis 使用一系列以photoshop進行縮放調整之speckle影像進行模擬

FFT-based Speckle Analysis 將每張影像取出31 X 31 pixels部分進行分析 31 X 31 100 pixels 100 pixels

FFT-based Speckle Analysis 取hann window，進行128點二維富利葉轉換後，只保留正頻率之magnitude部分資訊。 將所得之頻域資訊，經過帶通、投影。

FFT-based Speckle Analysis 用來分析相鄰frame之間，是否有頻率shift fz fx 投影 帶通

FFT-based Speckle Analysis 3000 100 2500 200 2000 300 1500 400 1000 500 500 600 1 2 3 4 5 6 7 8 9 10 11

FFT-based Speckle Analysis 2500 100 2000 200 300 1500 400 1000 500 500 600 1 2 3 4 5 6 7 8 9 10 11

FFT-based Speckle Analysis 現階段模擬結果，印證最初之原理假設。 尚未考慮散射子重新分佈、雜訊。 需進一步設計定量分析的方法。 可配合既有之speckle tracking技術。