Python Implementations of Standard Edge Detection Algorithms

Requirements

• NumPy
• Matplotlib
• Pillow

Sources

• Image from Davidwkennedy - http://en.wikipedia.org/wiki/File:Bikesgray.jpg - License
• Canny Edge Detector Wikipedia
• Marr-Hildreth Edge Detector Wikipedia

Canny Algorithm Code

• Smooth with Gaussian filter
• Differentiate via Sobel kernel
• Apply non-maximum suppression
• Apply double threshold to find weak and strong edges
• Edge tracking by hysteresis

Marr-Hildreth Algorithm Code

• Convolve with Laplacian of Gaussian
• Find Zero-Crossings

Results

Original

Canny

Marr-Hildreth