Perception for Autonomous Systems 31392:
Edge Detection
Lecturer: —PhD
10 Feb. 2020 DTU Electrical Engineering 2
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Edge Detection
• What is an Edge? • Image Derivative • Gradient
• Laplacian • Canny
10 Feb. 2020 DTU Electrical Engineering
Edge Detection
• What is and edge?
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Edge Detection
• What is and edge?
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Edge Detection
• What is and edge?
• Derivative of an Image:
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• The gradient is a vector which points in the direction of most rapid change in intensity:
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Gradient Simplified
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Gradient Simplified
• How would you define the 1D filter of the gradient:
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Gradient Simplified
• How would you define the 1D filter of the gradient:
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Gradient Simplified
• The gradient is defined by its orientation:
• and magnitude:
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• Practically:
• Magnitude:
• Orientation:
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Derivative Filters
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Preprocessing to Edge Detection
• In reality derivatives are very prone to noise Consider the following example:
• To overcome this issue we can smooth the signal beforehand
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Preprocessing to Edge Detection
• In reality derivatives are very prone to noise Consider the following example:
• To overcome this issue we can smooth the signal beforehand
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Laplacian of Gaussian
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Canny Edge Detection
Example of a Complex system: • Noise reduction
• Gradient calculation
• Non-maximum suppression
• Double threshold
• Edge Tracking by Hysteresis.
10 Feb. 2020 DTU Electrical Engineering 12
Perception for Autonomous Systems 31392:
Edge Detection
Lecturer: —PhD
10 Feb. 2020 DTU Electrical Engineering 13
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