Computer Vision (CV)

Libraries

• OpenCV
• ImageMagick
• vips - A fast image processing library with low memory needs.
• tesseract - OCR engine.

Concepts

• Haar-like feature - For object detection.
• Canny edge detector
• Hough transform
• Image Kernels

OpenCV Tips

• Docs
• iOS Install Tutorial
• Square Detection:
  • mukyasa/MMCamScanner (iOS)
  • card-io (Credit card scanning)

Bindings

• Node.js:
  • peterbraden/node-opencv

Common Functions

• Filtering:
  • Blur, GaussianBlur
  • MedianBlur (Median filter)
  • BilateralFilter (Bilateral filter) - Preserves edges.
• Morphology:
  • Erode (腐蚀), Dilate (膨胀)
  • Open (Erode -> Dilate): Remove noise.
  • Close (Dilate -> Erode): Close holes.

Modules Guide

• core: Basic structures, arrays, XML/YAML, OpenCL.
• imgproc: Image processing (filtering, geometric transformations, histograms, feature detection).
• highgui: High-level GUI (Swing-like).
• video: Video analysis (motion estimation, background subtraction).
• calib3d: Camera calibration, 3D reconstruction.
• features2d: Feature detection/description (SURF, ORB).
• objdetect: Object detection (Haar cascades, HOG).
• ml: Machine learning.