{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lec15.SfAR-CVF-Lecture

# problem def find straight lines images from

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: in y- direc-on }༇  Gradient Magnitude }༇  M= }༇  2 x f +f 2 y Gradient Direc-on θ = arctan fy fx Detection Stage - Threshold }༇  Gradient Magnitude }༇  Gradient Magnitude normalized b/w 0- 100 }༇  Applica-on of a threshold Gradient Magnitude Log of M to enhance visibility T = 10 T = 20 T = 40 T = 80 What about Gradient Direction? }༇  }༇  }༇  }༇  Gradient Direc-on is always perpendicular to edge Direc-on of most change of gray levels Thick edges can be eliminated using gradient direc-on Weak edges also captured in this manner Line Detection Using Edge Representation… }༇  }༇  Stereo matching problem Input: }༇  }༇  }༇  Computa-on }༇  }༇  Find corresponding features in two images Output }༇  }༇  Two images with disparity Camera Calibra-on informa-on Disparity in corresponding features is related to depth Edges and corners help in ﬁnding correspondences Finding Shapes from Edges Finding Shapes from Edges Edge Representation for Shape Analysis }༇  What about noisy edges? }༇  Problem Def.: Find straight lines… Images from: http://www.cogs.susx.ac.uk/users/davidy/teachvision/vision4.html Problems in Finding Lines Missing Data Noisy Data Mul-ple Lines Parameter Optimization: Least Squared Error Solutions }༇  Ficng a line to a set of data points… x y 1.3 5.7 2.4 7.3 3.4 10.5 4.6 11.8 5.3 13.9 6.6 16.3 6.4 15.3 8.0 17.9 8.9 20.8 9.2 20.9 }༇  Equa-on of best ﬁt line ? Line Fitting: Least Squared Error Solution }༇  Step 1: Iden-fy the model }༇  }༇  Step 2: Set up an error term which will give the goodness of every point with respect to the (unknown) m...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online