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Image segmentation using GMM

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Presentation on theme: "Image segmentation using GMM"— Presentation transcript:

1 Image segmentation using GMM
IBMR 2016 Hwk1

2 Requirement Input: Drawing white / red lines on image marking object / background, and the program will separate object from background. Output the 2-label (foreground / background) image with black and white. NO existing GMM code is allowed.

3 Image Segmentation using GMM
Using GMM to model the labeled object/background color distribution. For unlabeled pixels, GMMs tell that the pixel is much similar to foreground or background. N是一個Gaussian,pi是weight

4 GMM(Gaussian Mixture Model)

5 EM for GMMs

6 EM algorithm Randomly choose K (<=5) and initial K Gaussian Models G1…Gk Use GMM to model the pixel vectors (object or background) E-step: Evaluate the Responsibilities M-Step: Re-estimate Parameters. Get G1new ,…,Gknew Replace G with Gnew Repeat 2 ~ 5 until converge. Check Lecture 1 p.23~p.29 for more details.

7 EM algorithm E-step: Evaluate the Responsibilities
M-Step: Re-estimate Parameters E-step:計算每個點n對每個component k的反應,得到強弱反映tau M-step:利用E-step算出來的tau,計算出新的mu、sigma和pi

8 Segmentation considering neighbor pixels
Thinks an approach to consider neighbor pixels for segmentation on your own Simplify of Graph Cut (or you can implement complete Graph Cut) Output a 2-label image with black and white, and compare accuracy with ground truth 想一個方法將鄰居的點考慮進去,可以參考graph cut的想法作一些簡化或是直接時作graph cut,最後輸出一張黑白(背景/前景)影像,用來跟ground truth比較正確率

9 Grading GMM 80% Segmentation considering neighbor pixels 20% Bonus
Including foreground / background segmentation Segmentation considering neighbor pixels 20% Grades depend on the accuracy with ground truth Bonus Implement complete Graph cuts algorithm Due date: 2016/11/03 11:59 p.m. Upload to E3 Zipped file includes code/report/result image, file named as student number ex zip


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