Block 117: Contours & Object Detection

Concepts

• cv2.findContours() on binary image
• cv2.drawContours()
• Contour properties: area, perimeter, bounding box
• cv2.contourArea(), cv2.arcLength(), cv2.boundingRect()

Code Examples

See exercise below.

Exercise

Find all contours in a binary image. Draw the 3 largest ones. Draw bounding boxes around all detected contours with area > 500.

Homework

What preprocessing steps (threshold, blur, morph) give the best contour detection results? Experiment.