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期末 Demo 報告 Cross-based. 2012/08/13 指導教授:詹寶珠教授 報告者:王邦威. Outline. Flow chart Method Implement on GPU Experimental results. Introduction. left. right. Local base algorithm. L. R. y. P(Lx,Ly). P’( Rx,Ry ). Disparity= Lx-Rx. Flow chart. Support region construction. Matching cost. - PowerPoint PPT Presentation
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Electrical Engineering Department of National Cheng Kung University
1Smart Media & Intelligent Living Excellence Lab.
2012/08/13指導教授:詹寶珠教授
報告者:王邦威
期末 Demo 報告 Cross-based
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 2
Outline
Flow chart
Method
Implement on GPU
Experimental results
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 3
Introduction
left right
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 4
Local base algorithm
L R
Disparity= Lx-Rx
y
P(Lx,Ly) P’(Rx,Ry)
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 5
Flow chart
Support region construction
Matching cost
Cost aggregation
Winner-take-all
Post-processing
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab.
Cross-based local support region construction
Two constraints• L
• d
• 2
6
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab.
Locally adaptive matching cost aggregation
Matching cost
• CAD :• Ccensus : Hamming distance of the two strings that stand
for p and pd
7
String
R. Zabih and J. Woodfill, “Non-parametric local transforms for computing visual correspondence,” in Proc. ECCV, 1994, pp. 151–158.
2
左圖 右圖
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 8
Locally adaptive matching cost aggregation
Cost aggregation• d
Winner-take-all• f
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 9
Left/right consistency check
We apply occlusion treatment via left/right consistency checking to check the condition .
Then we fill in the disparity for invalidated pixels. For an invalidated pixel , we search its closest valid pixel to the left and to the right.
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 10
Implement on GPU
整合 CUDA和 Open CV• 建一個專案,將含有 cuda的程式碼部分包成一個 Dll檔• 對主函式和含有 Open CV的程式碼另外建一個專案,寫在
Cpp檔• 在利用到 GPU就呼叫 Dll檔
CPP檔(主程式且包含呼叫 Open CV程式片段 )
DLL檔(包含呼叫
GPU程式片段 )
GPU(kernel
function)
Host Device
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 11
Implement on GPU
Number of threads : width
Number of blocks : height
One block
Width
Height
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 12
Experimental results
384x288
執行時間 :0.058秒
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 13
Experimental results時間分析 -AD
原程式• 計算matching cost和水平區域 cost總和 :0.625秒• 長區域所花時間 :2.67秒• 計算垂直上每點的水平 cost總合和WTA:0.561秒• 後處理 :0.017秒• 總共 :3.941秒平行化的程式• 計算matching cost和水平區域 cost總和 :0.022秒• 長區域所花時間 :0.012秒• 計算垂直上每點的水平 cost總合和WTA:0.022秒• 後處理 :0.002秒• 總共 :0.058秒加速 68倍
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 14
Experimental results
384x288
執行時間 :0.273秒
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 15
Experimental results時間分析 -AD&Census
原程式• 計算 Census cost:1.646秒• 加總水平區域的 cost:0.406秒• 長區域 : 2.67秒• 計算垂直上每點的水平 cost總合和WTA:0.561秒• 後處理 :0.017秒• 總共 :5.684秒平行化的程式• 計算 Census cost:0.21秒• 加總水平區域的 cost:0.026秒• 長區域 :0.012秒• 計算垂直上每點的水平 cost總合和WTA:0.025秒• 後處理 :0.002秒• 總共 :0.273秒
加速 20倍
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 16
Conclusions
對於擁有許多不相依性計算的方法,可以很容易達到不錯的加速效能
適當的利用 share memory,可以達到更快的速度
Electrical Engineering Department of National Cheng Kung University
Smart Media & Intelligent Living Excellence Lab. 17
Thank for your attention!